Flexible Use of the NUSS in Non-Union Surgery: Value of Intraoperative Bone Loss Assessment and Overtreatment

Flexible Use of the NUSS in Non-Union Surgery: Value of Intraoperative Bone Loss Assessment and Overtreatment | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Method Article Flexible Use of the NUSS in Non-Union Surgery: Value of Intraoperative Bone Loss Assessment and Overtreatment Dos Santos Rocha Daniel, Bastin Pierre Antoine, Manon Julie, Cornu Olivier This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7611992/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The Non-Union Scoring System (NUSS) is the first multidimensional tool to guide treatment of fracture non-unions, but key parameters—particularly bone loss—may be underestimated preoperatively. We assessed (i) how intraoperative reassessment modifies NUSS scoring and algorithmic recommendations and (ii) whether our centre’s frequent use of combined mechanical and biological strategies (“overtreatment”) affects outcomes versus the Calori validation cohort. Methods We retrospectively reviewed 103 adults surgically treated for long-bone non-union at Cliniques Universitaires Saint-Luc (Brussels) from 2015–2023 with ≥12-month follow-up. NUSS was calculated preoperatively and recalculated immediately post-debridement from radiographs/CT; patients were stratified into NUSS therapeutic groups and compared with Calori et al. (2014). Outcomes were union, time to radiographic consolidation, and complications, analysed with binomial and Student’s t -tests (α=0.05). Results The tibia was the most affected site (54.4%), with high prevalence of infection (42.7%) and repeated surgery (≥2 procedures in 70%). Intraoperative reassessment revealed significantly larger bone defects, especially in group 3 (7.2 → 10.5 cm, p < 0.001), leading to NUSS score changes in 18 patients (17.5%), with reclassification in 2 cases (1.9%). In comparison with NUSS recommendations, overtreatment occurred frequently (94% in group 1, 87% in group 2), attributable to the recurrent, albeit non-systematic, use of biological stimulation. The overall union rate in our series was 83.0%, comparable to 85.5% in Calori’s cohort. Group 1 patients achieved higher union rates (97.0% vs. 86.9%, p = 0.058) and significantly shorter healing times (7.8 ± 1.6 vs. 8.8 ± 2.0 months, p = 0.04). No significant differences were found in groups 2 and 3, where outcomes were negatively influenced by infection and smoking. Conclusions The NUSS provides a robust framework for classification and treatment planning in non-unions, but intraoperative reassessment is essential to avoid underestimation of bone loss. Proactive addition of biological augmentation to mechanical revision achieved very high union and shorter healing in simple non-unions without added morbidity; benefits were less evident in complex cases, where infection and adverse biology predominate. NUSS should therefore be applied as a flexible guide, complemented by clinical judgment and tailored biological strategies. non-union pseudarthrosis NUSS score bone defect biological augmentation fracture healing Figures Figure 1 Figure 2 Figure 3 1. Introduction Non-union (pseudarthrosis) remains one of the most challenging complications in fracture care. Classically, it is defined as failure of bone healing within the expected timeframe despite apparently adequate initial management, with interruption of the reparative cascade, interfragmentary fibrous tissue, and absent cortical continuity. Epidemiologically, non-unions occur in roughly 5–10% of fractures—an incidence that varies by anatomic site, injury severity, and local/systemic risk factors[ 1 , 2 ]. Certain locations are particularly predisposed, notably the scaphoid, femoral neck, talus, tibia, and humerus[ 3 ]; the tibia is frequently involved because of its subcutaneous position and relatively vulnerable blood supply[ 4 ]. Septic non-union, although less common, represents a distinct entity with chronic inflammation, pathogen-driven osteolysis, and an impaired regenerative microenvironment, translating into poorer prognosis[ 5 ] and complex management pathways[ 6 ]. Despite widespread use, time-based definitions (e.g., the FDA’s ≥ 9-month criterion with no radiographic progression over the prior three months[ 7 ]) are limited because they lack standardized clinical/radiographic parameters and can delay recognition of cases with obvious early non-healing biology (e.g. large segmental defects or active infection). Clinically, non-union reflects perturbations of both mechanics and biology. Risk is modulated by fracture pattern and soft-tissue injury[ 8 ] (e.g., open Gustilo-Anderson type III), patient factors (notably smoking[ 9 ], diabetes, obesity[ 10 ], malnutrition, advanced age), iatrogenic issues (insufficient/overly rigid fixation in selected constructs[ 11 ]), and infection. Although traditional radiographic classifications—such as Weber and Cech’s[ 12 ] vital/reactive versus avital/areactive scheme, often described in terms of atrophic, hypertrophic, or oligotrophic pseudarthrosis—are still frequently cited, they provide an incomplete representation of the pathophysiologic heterogeneity; in particular, radiographic morphology shows limited correlation with vascularity[ 13 , 14 ]. Conceptually, contemporary management embraces the “diamond concept” [ 15 ] (Fig. 1 ) which frames union as the convergence of osteogenic cells, osteoinductive signals, an osteoconductive scaffold, adequate mechanical stability, and sufficient vascularity. Therapeutic strategies aim to restore missing components via stable fixation and biological augmentation (autograft, bone marrow aspirate concentrate, growth factors such as BMPs, and/or osteoconductive matrices), tailored to the non-union phenotype. Yet, because these determinants coexist and interact, single-axis classifications offer limited guidance on treatment intensity and sequencing. To address these shortcomings, Calori et al. introduced the Non-Union Scoring System (NUSS) in 2008[ 16 ] as the first multidimensional classification. NUSS integrates 15 parameters (Fig. 2 ) grouped into three categories: Bone-related factors – site of fracture, degree of comminution, presence of segmental defect, condition of bone ends, cortical contact, alignment, and stability of fixation. Soft-tissue envelope – quality of coverage, degree of scarring or adhesion, vascularization, and presence of infection. General patient factors – age, comorbidities such as diabetes or vascular disease, nutritional status, smoking, and systemic conditions affecting healing. Each parameter is weighted, and the sum is doubled to generate a score from 4 to 100. Based on this score, patients are stratified into four groups reflecting increasing biological and mechanical complexity. The score is coupled with a therapeutic algorithm known as the “ladder strategy” (Fig. 3 ): Group 1 (≤ 25 points) : usually simple non-unions, mainly mechanical in origin; treated with major revision of fixation (M) . Group 2 (26–50 points) : combined mechanical and biological compromise; treated with minor mechanical revision plus biological monotherapy (m + b) . Group 3 (51–75 points) : complex non-unions requiring major mechanical revision plus biological therapy (M + b) or minor mechanical revision plus biological polytherapy (m + B) . Group 4 (≥ 76 points) : very severe non-unions with poor biological and mechanical environment; strategies include M + B , sometimes extending to salvage procedures (arthrodesis, megaprosthesis, or even amputation). This scoring system was validated in 2014 on a 300-patient cohort[ 17 ], demonstrating strong predictive value for treatment planning and outcome, and it is now widely cited as a structured decision-making framework in complex non-unions. Nevertheless, NUSS presents practical limitations. Key parameters, such as the size of the bone defect and the vascularization of osseous tissue are frequently underestimated before surgery and can only be reliably assessed intraoperatively. This can shift the score and alter the theoretically recommended strategy. Moreover, in real-world practice, many teams tend to adopt more aggressive combined mechanical and biological treatments even in lower NUSS groups, aiming to maximize union probability and shorten healing time. Whether such “overtreatment” provides superior outcomes compared with NUSS-guided algorithms remains insufficiently investigated. Study objective. Building on these considerations, the present study (i) compares preoperative versus intraoperative assessment of bone defect and examines the resultant impact on the final NUSS score and the algorithm-driven therapeutic recommendation, and (ii) evaluates our centre’s tendency to frequently combine biological stimulation with hardware revision - even in lower NUSS groups - against the outcomes reported in Calori’s validation cohort, under the hypothesis that such an approach improves union rates and accelerates healing. 2. Materials and Methods Study design and population We conducted a single-centre retrospective study including 103 patients who underwent surgical management of long-bone non-union at Cliniques Universitaires Saint-Luc, Brussels, between 2015 and 2023. Ethical approval was obtained from the institutional review board (reference B403201523492). Clinical outcomes—including therapeutic modalities, union rates, and time to radiological consolidation—were compared with the reference cohort published by Calori et al. in 2014. Inclusion and exclusion criteria Eligible patients were adults (≥ 18 years) with non-union of a long bone, managed surgically, and with a minimum clinical follow-up of 12 months. Preoperative evaluation included complete blood count, C-reactive protein (CRP), white blood cell count, and glycated haemoglobin (HbA1c). Medication history (NSAIDs, corticosteroids) and comorbidities were systematically collected. Exclusion criteria were: patients < 18 years old, multiple non-unions, non-unions involving non-long bones (flat or short bones), immunosuppressive treatment, psychiatric disorders, active or prior malignancy, or ongoing chemotherapy. Data collection and definitions Demographic and clinical data included age at diagnosis, sex, body mass index (BMI), smoking status, diabetes, HIV status, anatomical site of non-union, fracture characteristics (open vs closed), initial treatment, and number of previous surgical procedures. Soft-tissue condition and need for flap coverage were also recorded. Non-union was defined according to the US Food and Drug Administration (FDA): absence of healing progression for at least nine months after fracture, with no radiological evidence of consolidation during the last three months. Union was defined as bridging callus across at least three of four cortices, obliteration of the fracture line, and restoration of cortical continuity. The NUSS score was calculated preoperatively and recalculated in the immediate postoperative period after debridement, based on radiographs or CT scans. Patients were classified into NUSS therapeutic groups: Group 1 (< 26) : major change of fixation system (M) Group 2 (26–50) : minor fixation correction (m) + biological monotherapy (b) Group 3 (51–75) : either major fixation + biological monotherapy (M + b), or minor fixation + biological polytherapy (m + B) Group 4 (> 75) : salvage strategies including amputation, arthrodesis, prosthesis, or megaprosthesis. Treatment modalities were recorded (single- vs two-stage procedure, with or without allograft, with or without biological adjuncts). Outcomes included union rate, time to radiological healing, complications, and reasons for surgical revision in case of failure. Statistical analysis Data were analysed using SPSS software. After NUSS scoring, patients were allocated into therapeutic groups and compared with the reference cohort of Calori et al. The significance threshold was set at p < 0.05. Union rates were compared using a binomial test for proportions, and mean healing time was analysed with a one-sample Student’s t-test. 3. Results 3.1 Patient characteristics The main demographic and clinical characteristics of the cohort are summarized Table 1 . Among the 103 included patients, the majority were male (66%), and nearly 70% were overweight or obese. Approximately one-third were smokers (30.1%), a well-recognized risk factor for impaired bone healing. Diabetes was present in 8.7%, and in most cases glycaemic control was adequate (HbA1c < 10% in 80% of diabetic patients), limiting its negative influence on consolidation. Table 1 Population characteristics Population characteristics N % Sex Masculine Feminine 68 35 66.0 34.0 BMI Lean ( 30) 1 34 28 40 1.0 33.0 27.2 38.8 Smoking No Yes 72 31 69.9 30.1 Diabetes No Yes 94 9 91.3 8.7 Glycated Hb (%) No 10% 93 8 2 90.3 7.8 1.9 Fracture Closed Open 81 22 78.6 21.4 Initial treatment Conservative External fixator Internal intramedullary fixation Extra medullary internal fixation Int Fix Ext Med + bone graft 2 24 22 45 10 1.9 23.3 21.4 43.7 9.7 Number of previous surgeries < 2 4 33 42 28 32.0 40.8 27.2 Bone lesion Humerus Femur Tibia 3 44 56 2.9 42.7 54.4 Infection No Yes 59 44 57.3 42.7 CRP (mg/L) 20 89 14 86.4 13.6 WC (cells/µL) 12000 92 11 89.3 10.7 Total population 103 100 Regarding the initial trauma, 21.4% of fractures were open, and 98% were surgically treated. The most common primary management strategy was osteosynthesis—either plate fixation or intramedullary nailing—in over 60% of cases. In 10% of patients, bone grafting was combined with fixation at the time of initial surgery. The complexity of the cohort is illustrated by the fact that 70% had undergone at least two prior surgeries before definitive non-union treatment. The tibia was the most frequently affected site (54.4%), followed by the femur (42.7%). At the time of surgery, 42.7% had a history of local infection, though only 13.6% showed elevated CRP (> 20 mg/L) and 10.7% leucocytosis, suggesting that a minority had active infection at the time of intervention. The mean follow-up was 34 months. Non-consolidation with the need for further surgery occurred in 18 patients (17%), mainly due to persistent infection (n = 9) or refracture on persistent non-union with implant failure (n = 3). 3.2 Distribution according to NUSS groups The distribution of patients according to NUSS classification is shown in Table 2 . Most patients belonged to group 2 (44.7%) or group 1 (32.0%), while group 3 accounted for 23.3%. No patients were classified in group 4. Table 2 Separation of the population into the different NUSS groups ; The postoperative score was obtained after measurement of the bone defect after debridement NUSS SCORE N % Pre-op Post-op Mean Median Max Min StDev Mean Median Max Min StDev Group 1 33 32.0% 19.9 20 24 10 3.74 19.9 20 24 10 3.74 NUSS 0–25 Group 2 46 44.7% 36.3 35 50 26 7.39 37.4 36 54 26 7.90 NUSS 26–50 Group 3 24 23.3% 58.8 56 72 52 6.29 59.5 56 72 52 6.86 NUSS 51–75 Group 4 NUSS 76–100 0 In group 1, mean NUSS scores remained stable between pre- and postoperative assessments (19.9 ± 3.7, p = 0.180). In group 2, scores showed a small, non-significant increase (36.3 → 37.4, p = 0.513). In contrast, group 3 demonstrated a statistically significant increase in mean NUSS score (58.8 → 59.5, p = 0.00027), suggesting either more precise intraoperative reassessment or a genuine increase in defect size after radical debridement. Table 3 highlights the distribution of risk factors across NUSS groups. Notably, infection was present in 96% of group 3 patients, while smoking was most prevalent in group 3 (54%) compared with group 2 (39%) and absent in group 1. Table 3 Distribution of patients by group, by smoking and presence of infected non-union Groups N patients in each group Smoking % Infection % 1 33 0 0% 2 6% 2 46 18 39% 19 41% 3 24 13 54% 23 96% N total patients 103 31 30% 44 43% 3.3 Bone defect analysis Pre- and postoperative bone defect measurements are detailed in Table 4 . A general trend toward larger postoperative defects was observed. Table 4 Pre- and post-operative bone defect (cm) Bone defect size (cm) N % Pre-op Post-op Mean Median Max Min StDev Mean Median Max Min StDev Group 1 33 32.0% 0.5 0.5 2 10 0.44 0.7 0.5 8 0 1.39 NUSS 0–25 Group 2 46 44.7% 1.3 0.95 4.4 0 1.13 2.8 1.45 19 0 3.60 NUSS 26–50 Group 3 24 23.3% 7.2 5.55 19 1.1 5.43 10.5 9.55 29 2.6 6.07 NUSS 51–75 Group 4 NUSS 76–100 0 In group 1, mean defect size increased slightly (0.5 → 0.7 cm, p = 0.180, Wilcoxon test). In group 2, mean defect size increased from 1.3 to 2.8 cm (p = 0.513, Wilcoxon test). In group 3, the difference was statistically significant, with mean bone loss increasing from 7.2 to 10.5 cm (p = 0.00027, paired t-test). Overall, 18 patients (17.5%) experienced a change in their NUSS score between pre- and postoperative assessments, and 2 patients (1.9% of the total cohort) were reclassified into a higher NUSS group (group 2 → group 3) (Table 5 ; Graphic 1). Table 5 Postoperative NUSS score change N % How many have had a change in NUSS score pre and post? 18 17.5% How many have changed NUSS groups? 2 11.1% (ou 1.9% total pop) 3.4 Overtreatment Comparison of actual treatments with those recommended by the NUSS protocol revealed a strong tendency toward overtreatment (Table 6 ). Table 6 % overtreatment for each group: M = complete change in fixation system / m = minor change in fixation system / b = monotherapy biologic therapy / B = biologic combination therapy; treatment in bold type = treatment that corresponds to the NUSS protocol OR under treatment Group 1 NUSS Protocol Treatment N % overtreatment M m + b 1 93.9% M + b 13 m + B 11 M + B 6 M 2 Total : 33 Group 2 m + b M 1 87.0% m + b 5 M + b 6 m + B 13 M + B 21 Total : 46 Group 3 M + b m + B 5 12.5% M + B M + B 16 Megaprothèse 1 Arthrodèse 2 Total : 24 In group 1 , 93.9% of patients received more intensive treatment than recommended, most commonly combining mechanical revision with biological stimulation. In group 2 , the overtreatment rate was 87.0% , with frequent use of major fixation changes or biological polytherapy. In group 3 , overtreatment was limited to 12.5% , as most patients received treatment aligned with protocol recommendations. Only a few underwent salvage strategies such as arthrodesis or megaprosthesis implantation. 3.5 Union rates Union rates for our cohort and for Calori’s reference series are presented in Table 7 . The overall consolidation rate in our population was 83.0%, closely comparable to the 85.5% reported by Calori et al. This similarity suggests that our treatment strategy—despite a high frequency of overtreatment relative to NUSS recommendations—achieved outcomes consistent with those of the reference cohort. Table 7 Healing rate (%) Healing rate NUSS Calori et al. Treatment p value 1 86.9% 97.0% 0.058 2 87.1% 78.3% 0.065 3 82.1% 73.9% 0.123 Global 85.5% 83.0% When stratified by NUSS subgroup, important differences emerge. In group 1 (NUSS ≤ 25), union was achieved in 97.0% of patients, which is notably higher than the 86.9% reported by Calori. This difference approached statistical significance (p = 0.058). While not formally significant, the trend strongly suggests that the systematic addition of biological stimulation in our series may have contributed to superior outcomes in this subgroup. Clinically, this translates to a very low risk of persistence of non-union in “simple” cases when treated more aggressively. In group 2 (NUSS 26–50), our consolidation rate was 78.3%, lower than the 87.1% in Calori’s study, though again without statistical significance (p = 0.065). This finding is somewhat counterintuitive given our frequent overtreatment in this group (87%). One likely explanation is the high prevalence of infection (41%) and smoking (39%) in our group 2 patients—factors well recognized to impair bone healing and not fully accounted for in the NUSS algorithm. In group 3 (NUSS 51–75), our union rate was 73.9% compared to 82.1% in Calori (p = 0.123). Although not statistically significant, the lower rate highlights the inherent complexity of managing biologically and mechanically compromised non-unions, where systemic and local factors (chronic infection, vascularity, quality of soft tissues) may dominate outcomes regardless of the treatment strategy. Overall, while our global results are comparable to those of Calori, the subgroup analysis emphasizes that overtreatment appears most beneficial in group 1 non-unions, but less impactful in more complex cases where biological and systemic risk factors prevail. 3.6 Time to consolidation Radiological consolidation times are shown in Table 8 . Table 8 Radiological consolidation (in months) Radiological consolidation (in months) NUSS Calori et al. Treatment p value 1 8.8 +- 2.0 7.8+-1.6 0.04 2 9.0+- 1.8 8.7+-1.3 0.291 3 9.5+-1.4 10.2+-1.5 0.064 In group 1, the mean time to consolidation was significantly shorter in our series (7.8 ± 1.6 months) than in Calori’s (8.8 ± 2.0 months, p = 0.04). This reduction of approximately one month is both statistically significant and clinically relevant. Earlier union in this group may be attributed to the systematic use of biological adjuncts (e.g., bone marrow aspirate concentrate combined with demineralized bone matrix), which are simple, minimally invasive, and without significant morbidity. From a clinical standpoint, this shortened healing time can lead to faster weight-bearing, earlier rehabilitation, and improved patient quality of life. In group 2, consolidation occurred in 8.7 ± 1.3 months versus 9.0 ± 1.8 months in Calori (p = 0.291). Although numerically shorter, the difference was not statistically significant. This suggests that, despite frequent overtreatment, the biological and systemic risk profile of these patients may have limited the effectiveness of additional interventions. In group 3, consolidation required 10.2 ± 1.5 months in our cohort, compared with 9.5 ± 1.4 months in Calori (p = 0.064). Although the difference did not reach significance, the trend toward longer healing times underscores the difficulty of achieving rapid consolidation in severe cases, where bone defect size, poor vascularity, and infection are dominant limiting factors. Taken together, these findings suggest that overtreatment is particularly effective in reducing healing times in group 1 non-unions, but less so in groups 2 and 3, where systemic and biological risk factors exert a stronger influence. 3.7 Success rates by treatment intensity As illustrated in Graphic 2, no failures were reported in patients who were undertreated relative to NUSS recommendations. Among patients treated according to protocol, the success rate was 78%, while those receiving more intensive treatment achieved a higher success rate of approximately 85%. 4. Discussion The Non-Union Scoring System (NUSS) represents, to our knowledge, the first comprehensive classification system for non-unions to adopt a truly integrative approach, combining clinical, biological, radiological, and mechanical parameters in order to guide personalized treatment strategies. Its philosophy is consistent with the principles of evidence-based medicine: relying on objective, reproducible criteria while maintaining a pragmatic orientation, namely to provide clinicians with therapeutic recommendations adapted to the individual patient and to the specific complexity of the non-union. Compared with earlier classifications, which were often limited to purely radiological or anatomical features (e.g. Weber and Cech), NUSS distinguishes itself by its breadth and granularity. The system explicitly incorporates systemic risk factors—including age, comorbidities, smoking, and infection—and assigns them differentiated weights based on their presumed impact on healing potential. This weighted approach is coherent with extensive literature documenting, for example, the inhibitory role of smoking on osteogenesis[ 18 ]. Perhaps most importantly, NUSS links its classification to a structured therapeutic ladder, ranging from relatively conservative revision of fixation in simple cases to complex mechanical and biological reconstruction, and extending to salvage options such as megaprosthesis or amputation in the most severe scenarios. In this way, NUSS provides a structured framework for standardization while also accommodating inter-patient variability. a) Preoperative versus intraoperative assessment of bone defects Our first hypothesis was that discrepancies between preoperative and intraoperative bone defect assessments might shift patient classification and alter the corresponding treatment recommendation. Indeed, our data confirmed a systematic trend toward larger bone defects postoperatively , most pronounced in group 3 patients. This can be explained by the more extensive debridement typically required in complex cases, which exposes viable bone ends at the cost of enlarging the defect, as well as by the limited sensitivity of preoperative imaging in distinguishing viable from necrotic or sclerotic bone. Although 17.5% of patients experienced a change in their NUSS score between pre- and postoperative assessments, only 2 patients (1.9%) were reclassified into a higher therapeutic group. This low reclassification rate supports the overall robustness of preoperative NUSS scoring as a surgical planning tool. However, in these two cases, treatment escalation (from minor mechanical revision with biological monotherapy to major revision with biological polytherapy) was indeed warranted—and both patients achieved successful union. Importantly, the strategy adopted by our team was consistent with group 3 recommendations, even though preoperative scoring had placed them in group 2. These findings underscore that rigid adherence to NUSS may underestimate therapeutic needs in selected cases , reinforcing the importance of intraoperative reassessment and clinical judgment. b) Clinical practice and overtreatment Our second hypothesis concerned the gap between NUSS recommendations and our institutional practice. We anticipated—and confirmed—a systematic tendency toward overtreatment , particularly in lower NUSS categories. In group 1, 94% of patients received more intensive treatment than recommended, typically involving both mechanical revision and biological stimulation. Similarly, 87% of group 2 patients were “over-treated.” By contrast, overtreatment was rare (12.5%) in group 3, where most patients received treatment aligned with protocol recommendations. This proactive strategy is rooted in the belief that the systematic addition of osteoinductive or osteoconductive adjuvants improves consolidation, even in apparently simple non-unions. Our results partially validate this philosophy. In group 1, our union rate reached 97% , compared with 86.9% in Calori’s series (p = 0.058), suggesting a possible clinical benefit of routine biological augmentation. In group 2, however, despite frequent overtreatment, our union rate was lower ( 78.3% vs. 87.1% , p = 0.065). This paradox may reflect the high burden of risk factors in our cohort — 39% smokers and 41% with infection in group 2 alone — factors strongly predictive of impaired healing. In group 3, outcomes were poorer overall, regardless of treatment intensity, underscoring the complexity of advanced non-unions. c) Impact on time to consolidation With respect to bone healing time, a significant difference was observed in group 1: an average of 7.8 months with our protocol versus 8.8 months in Calori’s study. This one-month reduction is both clinically and statistically meaningful (p = 0.04), particularly regarding functional recovery and patient quality of life. A similar, though non-significant, trend was noted in group 2, which may reflect the beneficial impact of a more aggressive treatment strategy. The intraoperative use of bone marrow aspirate harvested from the iliac crest, concentrated by centrifugation, and combined with demineralized bone matrix (DBM) and frozen cancellous bone—as applied in several cases within our cohort—proved to be a simple, minimally invasive procedure without significant morbidity. Numerous studies have documented the positive effect of this approach on bone regeneration[ 19 , 20 ], primarily through the contribution of mesenchymal stem cells, cytokines, and growth factors. It therefore appears reasonable to consider this technique an effective therapeutic adjuvant, even in cases of pseudarthrosis initially classified as simple. d) Outcomes relative to NUSS recommendations When analysed by treatment adherence, patients treated strictly according to NUSS recommendations achieved a success rate of 78%, while those treated more intensively reached 85%. Notably, no failures were recorded among undertreated patients, though the small sample size warrants caution in interpretation. These findings suggest that overtreatment did not compromise outcomes and may even have conferred a modest benefit, especially in group 1. However, the high prevalence of infection in our series (43%) likely tempered overall success rates. e) Limitations of NUSS: toward a dynamic interpretation Despite its many strengths, the NUSS has inherent limitations. A major concern lies in the potential mismatch between the biological phenotype of the non-union and its classification within the score. For example, an atrophic non-union without systemic risk factors may be scored as group 1, yet by its biological nature it clearly warrants targeted stimulation[ 21 ]. This illustrates the need for a dynamic interpretation of NUSS , integrating both the objective criteria defined by the score and the morphological, biological, and histological features of the non-union site. Ultimately, while NUSS constitutes a major step forward in standardization and therapeutic guidance, it cannot replace clinical expertise and surgical judgment. The integration of local biology, patient history, infection status, and technical feasibility of reconstructive options remains indispensable for truly personalized management. 5. Conclusion Our critical evaluation of the NUSS score in clinical practice confirms its value as an integrative and pragmatic tool for the assessment of non-unions, while also highlighting important limitations in real-world application. By combining clinical, mechanical, biological, and radiological parameters, NUSS represents a significant step toward personalized orthopaedic care based on reproducible criteria capable of guiding tailored treatment strategies. Our study demonstrates the robustness of preoperative NUSS scoring , with only 1.9% of patients reclassified into a different therapeutic group after surgery, despite notable discrepancies between preoperative imaging and intraoperative findings. This overall stability validates the score as a surgical planning tool, but also emphasizes the need for flexible interpretation , particularly when intraoperative bone loss is underestimated. From a therapeutic perspective, our cohort revealed a clear trend toward overtreatment , especially in group 1 non-unions, where we systematically combined mechanical revision with biological stimulation beyond NUSS recommendations. This approach resulted in a remarkably high union rate (97%) and a significantly shorter healing time, without added morbidity. These findings suggest a real clinical benefit and support the use of minimally invasive biological adjuvants (such as bone marrow aspirate combined with DBM) even in apparently simple non-unions. At the same time, they raise questions about the cost-effectiveness of overtreatment, particularly in relation to its potential to reduce healing times, increase union rates, and limit the need for reoperation. Conversely, the less favourable outcomes observed predominantly in group 2—despite the frequent use of overtreatment—highlight the limitations of a uniform strategy and the multifactorial complexity of bone healing. This disparity suggests that certain determinants, particularly those of a biological or local tissue nature, are more intricate than those accounted for in the NUSS score or currently integrated into clinical practice. It therefore supports the need for an expanded model that more precisely incorporates the condition of the non-union site (e.g., vascularization, histological features, chronicity), and potentially for a future adaptation of the score to include osteoinductive signalling and the cellular microenvironment, concepts derived from the Diamond Theory. Ultimately, our findings highlight the importance of interpreting NUSS in a dynamic and nuanced way . While it provides a valuable framework for standardization and decision-making, NUSS should be regarded as a flexible guide , to be enriched by clinical expertise, biological characteristics of the non-union, and the technical feasibility of reconstructive options. Within this perspective, the rational use of biological augmentation—even in simple cases—appears justified when the objective is to optimize both union rate and healing time. The future of non-union management likely lies in bridging classification tools such as NUSS with biological and molecular models, leading to personalized treatment protocols that integrate clinical, mechanical, and biological parameters. This approach will help standardize best practices while optimizing functional outcomes within an evidence-based framework. Declarations Acknowledgements None Authors’ contributions Study design: DSRD and OC. Data collection/validation: DSRD and BPA. Data analysis: MJ. Result interpretation: DSRD and OC. Reporting and editing: DSRD. Project guarantor: DSRD and OC. The authors read and approved the final manuscript. Funding None Availability of data and materials Data will be available upon request by the first author DSRD. Ethics approval and consent to participate Ethical approval was obtained from the Ethics Committee under reference number B403201523492. Competing interests The authors declare that they have no conflict of interest. References Brinker MR, O’Connor DP. Nonunions: evaluation and treatment. In: Bucholz RW, Heckman JD, Court-Brown CM, Tornetta P, editors. Rockwood and Green’s Fractures in Adults. 10th ed. Philadelphia: Lippincott Williams & Wilkins; 2022. Calori GM, Albisetti W, Agus A, et al. Risk factors contributing to fracture non-unions. Injury. 2007;38 (Suppl ): SS11–8. doi: 10.1016/S0020-1383(07)80004-0. Hak DJ, Fitzpatrick D, Bishop JA, et al. Delayed union and nonunions: epidemiology, clinical issues, and financial aspects. Injury. 2014;45(Suppl 2):S3–7. doi: 10.1016/j.injury.2014.04.002. Tzioupis C, Giannoudis PV. Prevalence of long-bone non-unions. Injury. 2007;38(Suppl 2):S3–9. doi: 10.1016/s0020-1383(07)80003-9. Foster AL, Moriarty TF, Trampuz A, et al. Fracture-related infection: current methods for prevention and treatment. Expert Rev Anti Infect Ther. 2020 Apr;18(4):307-321. doi: 10.1080/14787210.2020.1729740 Calori GM, Mazza E, Colombo M, et al. The use of bone-graft substitutes in large bone defects: any specific needs? Injury. 2011;42(Suppl 2):S56–63. doi: 10.1016/j.injury.2011.06.011. Wittauer M, Burch MA, McNally M, et al. Definition of long-bone nonunion: A scoping review of prospective clinical trials to evaluate current practice. Injury. 2021 Nov;52(11):3200-3205. doi: 10.1016/j.injury.2021.09.008. Zura R, Mehta S, Della Rocca GJ, et al. Biological risk factors for nonunion of bone fracture. JBJS Rev. 2016;4(1):01874474. doi: 10.2106/JBJS.RVW.O.00008. Patel RA, Wilson RF, Patel PA, et al. The effect of smoking on bone healing: a systematic review. Bone Joint Res. 2013;2(6):102–111. doi: 10.1302/2046-3758.26.2000142. Jensen SS, Jensen NM, Gundtoft PH, et al. Risk factors for nonunion following surgically managed, traumatic, diaphyseal fractures: a systematic review and meta-analysis. EFORT Open Rev. 2022 Jul 5;7(7):516-525. doi: 10.1530/EOR-21-0137. Perren SM. Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation. Clin Orthop Relat Res. 2002;(398):7–24. doi: 10.1302/0301-620x.84b8.13752. Weber BG, Oldrich C, Konstam PG. Bern: Hans Huber Publishers; 1976. Pseudarthrosis: Pathophysiology, biomechanics, therapy, results; p. 323. Reed AAC, Joyner CJ, Brownlow HC, et al. Human atrophic fracture non-unions are not avascular. Journal of Orthopaedic Research. 2002;20(3):593–599. doi: 10.1016/S0736-0266(01)00142-5. Brownlow HC, Reed A, Simpson AHRW. The vascularity of atrophic non-unions. Injury. 2002;33(2):145–150. doi: 10.1016/s0020-1383(01)00153-x. Giannoudis PV, Einhorn TA, Marsh D. Fracture healing: the diamond concept. Injury. 2007;38(Suppl 4):S3–S6. doi: 10.1016/s0020-1383(08)70003-2. Calori GM, Phillips M, Jeetle S, et al. Classification of non-union: need for a new scoring system? Injury. 2008;39(Suppl 2):S59–63. doi: 10.1016/S0020-1383(08)70016-0. Calori GM, Colombo M, Mazza EL, et al. Validation of the Non-Union Scoring System in 300 long bone non-unions. Injury. 2014 Dec;45 Suppl 6:S93-7. doi: 10.1016/j.injury.2014.10.030. Bydon M, De la Garza-Ramos R, Abt NB, et al. Impact of smoking on complication and pseudarthrosis rates after single- and 2-level posterolateral fusion of the lumbar spine. Spine (Phila Pa 1976). 2014 Oct 1;39(21):1765-70. doi: 10.1097/BRS.0000000000000527. Impieri L, Pezzi A, Hadad H, et al. Orthobiologics in delayed union and non-union of adult long bones fractures: A systematic review. Bone Rep. 2024 Apr 6;21:101760. doi: 10.1016/j.bonr.2024.101760. Kaspiris A, Hadjimichael AC, Vasiliadis ES, et al. Therapeutic Efficacy and Safety of Osteoinductive Factors and Cellular Therapies for Long Bone Fractures and Non-Unions: A Meta-Analysis and Systematic Review. J Clin Med. 2022 Jul 4;11(13):3901. doi: 10.3390/jcm11133901. Yang, J., Zhang, X., Liang, W. et al. Efficacy of adjuvant treatment for fracture nonunion/delayed union: a network meta-analysis of randomized controlled trials. BMC Musculoskelet Disord 23, 481 (2022). doi:10.1186/s12891-022-05407-5. Graphic Graphic 1 and 2 are available in the Supplementary Files section Additional Declarations No competing interests reported. Supplementary Files Graph1.png Graphic 1 : Pre- and post-operative NUSS score, per patient Graph2.png Graphic 2 : comparison of the number of patients cured according to the treatment received compared to the treatment proposed by the NUSS protocol Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7611992","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Method Article","associatedPublications":[],"authors":[{"id":514789821,"identity":"c53d9dee-3289-4f44-90e4-05ee86b6a88d","order_by":0,"name":"Dos Santos Rocha Daniel","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYBACCSBmZjCQkANxDjwgRYsxWEsC8VoYGBIbQDyitEi2nzH8XFBgkT4/7PBDoC12croNBLRI8+QYS88wkMjdeDvNAKgl2djsAAEtcgw5BtI8IC2zE0BaDiRuI6iF/43xb6CWdMPZ6R+I0yItkWMGsiVBXjqHSFskZzwrswb6xXCDdE7BgQQDIvwicT558+2CP3Xy8rPTN3/4UGEnR1ALAwOHAZgyAKs0IKgcBNgfgCn5BqJUj4JRMApGwUgEAOBAQFAmjnsFAAAAAElFTkSuQmCC","orcid":"","institution":"Cliniques Universitaires Saint-Luc UCL","correspondingAuthor":true,"prefix":"","firstName":"Dos","middleName":"Santos Rocha","lastName":"Daniel","suffix":""},{"id":514789822,"identity":"2d1c8d3c-8722-44e3-bccf-ddb083282346","order_by":1,"name":"Bastin Pierre Antoine","email":"","orcid":"","institution":"Cliniques Universitaires Saint-Luc UCL","correspondingAuthor":false,"prefix":"","firstName":"Bastin","middleName":"Pierre","lastName":"Antoine","suffix":""},{"id":514789823,"identity":"f7b4b5e0-a327-4637-9637-24342771300b","order_by":2,"name":"Manon Julie","email":"","orcid":"","institution":"Cliniques Universitaires Saint-Luc UCL","correspondingAuthor":false,"prefix":"","firstName":"Manon","middleName":"","lastName":"Julie","suffix":""},{"id":514789824,"identity":"bd6b1be7-bcc9-41cb-9b9b-52ee8866d8f2","order_by":3,"name":"Cornu Olivier","email":"","orcid":"","institution":"Cliniques Universitaires Saint-Luc UCL","correspondingAuthor":false,"prefix":"","firstName":"Cornu","middleName":"","lastName":"Olivier","suffix":""}],"badges":[],"createdAt":"2025-09-14 10:23:26","currentVersionCode":1,"declarations":{"humanSubjects":false,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":false,"humanSubjectConsent":false,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-7611992/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7611992/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":91515277,"identity":"375577f3-3ab2-4f82-968b-0c0174f9243b","added_by":"auto","created_at":"2025-09-17 09:12:36","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":42185,"visible":true,"origin":"","legend":"\u003cp\u003eDiamond theory\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7611992/v1/76fec1a385991256b8986d30.png"},{"id":91517079,"identity":"3c51ee3e-f1cc-40bf-a147-e1d202535c96","added_by":"auto","created_at":"2025-09-17 09:28:36","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":268249,"visible":true,"origin":"","legend":"\u003cp\u003eThe NUSS score –calculating the overall score (adapted from Calori et al 2008)\u003csup\u003e16\u003c/sup\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7611992/v1/5d39a8769f933bba49591094.png"},{"id":91515278,"identity":"731ffbe6-07c9-4b3d-ab6a-d27563451d10","added_by":"auto","created_at":"2025-09-17 09:12:36","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":60534,"visible":true,"origin":"","legend":"\u003cp\u003eThe Ladder Strategy\u0026nbsp;: M = complete change of the fixation system / m = minor change of the fixation system / b = biological treatment with monotherapy / B = biological treatment with polytherapy / Group 1 (\u0026lt;26): M / Group 2 (26–50): m + b (minor change of fixation system + biological monotherapy) / Group 3 (51–75): M + b (major change of fixation system + biological monotherapy) OR m + B (minor change of fixation system + biological polytherapy) / Group 4 (\u0026gt;75): M + B (amputation/arthrodesis/prosthesis), adapted from Calori et al. 2014\u003csup\u003e16\u003c/sup\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7611992/v1/c32378f58ebae4ae806c70ae.png"},{"id":91758601,"identity":"407576b7-41a3-4334-85a3-7633ec21539f","added_by":"auto","created_at":"2025-09-20 07:53:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2066301,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7611992/v1/b1943f53-e04b-4852-8dde-74e5f31202e7.pdf"},{"id":91515951,"identity":"2416095e-3e16-474d-816f-b96b32b7e5a9","added_by":"auto","created_at":"2025-09-17 09:20:36","extension":"png","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":79094,"visible":true,"origin":"","legend":"\u003cp\u003eGraphic 1 : Pre- and post-operative NUSS score, per patient\u003c/p\u003e","description":"","filename":"Graph1.png","url":"https://assets-eu.researchsquare.com/files/rs-7611992/v1/dcbca498ae9c356edf07e27b.png"},{"id":91517078,"identity":"35c0d20b-d006-42e1-9396-98e29235812b","added_by":"auto","created_at":"2025-09-17 09:28:36","extension":"png","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":27066,"visible":true,"origin":"","legend":"\u003cp\u003eGraphic 2 : comparison of the number of patients cured according to the treatment received compared to the treatment proposed by the NUSS protocol\u003c/p\u003e","description":"","filename":"Graph2.png","url":"https://assets-eu.researchsquare.com/files/rs-7611992/v1/8b9aec328cadd72def87e0f1.png"}],"financialInterests":"No competing interests reported.","formattedTitle":"Flexible Use of the NUSS in Non-Union Surgery: Value of Intraoperative Bone Loss Assessment and Overtreatment","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eNon-union (pseudarthrosis) remains one of the most challenging complications in fracture care. Classically, it is defined as failure of bone healing within the expected timeframe despite apparently adequate initial management, with interruption of the reparative cascade, interfragmentary fibrous tissue, and absent cortical continuity. Epidemiologically, non-unions occur in roughly 5\u0026ndash;10% of fractures\u0026mdash;an incidence that varies by anatomic site, injury severity, and local/systemic risk factors[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Certain locations are particularly predisposed, notably the scaphoid, femoral neck, talus, tibia, and humerus[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]; the tibia is frequently involved because of its subcutaneous position and relatively vulnerable blood supply[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Septic non-union, although less common, represents a distinct entity with chronic inflammation, pathogen-driven osteolysis, and an impaired regenerative microenvironment, translating into poorer prognosis[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] and complex management pathways[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDespite widespread use, time-based definitions (e.g., the FDA\u0026rsquo;s\u0026thinsp;\u0026ge;\u0026thinsp;9-month criterion with no radiographic progression over the prior three months[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]) are limited because they lack standardized clinical/radiographic parameters and can delay recognition of cases with obvious early non-healing biology (e.g. large segmental defects or active infection). Clinically, non-union reflects perturbations of both mechanics and biology. Risk is modulated by fracture pattern and soft-tissue injury[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] (e.g., open Gustilo-Anderson type III), patient factors (notably smoking[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], diabetes, obesity[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], malnutrition, advanced age), iatrogenic issues (insufficient/overly rigid fixation in selected constructs[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]), and infection. Although traditional radiographic classifications\u0026mdash;such as Weber and Cech\u0026rsquo;s[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] vital/reactive versus avital/areactive scheme, often described in terms of atrophic, hypertrophic, or oligotrophic pseudarthrosis\u0026mdash;are still frequently cited, they provide an incomplete representation of the pathophysiologic heterogeneity; in particular, radiographic morphology shows limited correlation with vascularity[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eConceptually, contemporary management embraces the \u0026ldquo;diamond concept\u0026rdquo; [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) which frames union as the convergence of osteogenic cells, osteoinductive signals, an osteoconductive scaffold, adequate mechanical stability, and sufficient vascularity. Therapeutic strategies aim to restore missing components via stable fixation and biological augmentation (autograft, bone marrow aspirate concentrate, growth factors such as BMPs, and/or osteoconductive matrices), tailored to the non-union phenotype. Yet, because these determinants coexist and interact, single-axis classifications offer limited guidance on treatment intensity and sequencing.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eTo address these shortcomings, Calori et al. introduced the Non-Union Scoring System (NUSS) in 2008[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] as the first multidimensional classification. NUSS integrates 15 parameters (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) grouped into three categories:\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003col\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eBone-related factors\u003c/b\u003e \u0026ndash; site of fracture, degree of comminution, presence of segmental defect, condition of bone ends, cortical contact, alignment, and stability of fixation.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eSoft-tissue envelope\u003c/b\u003e \u0026ndash; quality of coverage, degree of scarring or adhesion, vascularization, and presence of infection.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003cspan\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGeneral patient factors\u003c/b\u003e \u0026ndash; age, comorbidities such as diabetes or vascular disease, nutritional status, smoking, and systemic conditions affecting healing.\u003c/p\u003e\u003c/li\u003e\u003c/span\u003e\u003c/ol\u003e\u003c/p\u003e\u003cp\u003eEach parameter is weighted, and the sum is doubled to generate a score from 4 to 100. Based on this score, patients are stratified into four groups reflecting increasing biological and mechanical complexity. The score is coupled with a \u003cb\u003etherapeutic algorithm known as the \u0026ldquo;ladder strategy\u0026rdquo;\u003c/b\u003e (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e):\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 1 (\u0026le;\u0026thinsp;25 points)\u003c/b\u003e: usually simple non-unions, mainly mechanical in origin; treated with \u003cb\u003emajor revision of fixation (M)\u003c/b\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 2 (26\u0026ndash;50 points)\u003c/b\u003e: combined mechanical and biological compromise; treated with \u003cb\u003eminor mechanical revision plus biological monotherapy (m\u0026thinsp;+\u0026thinsp;b)\u003c/b\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 3 (51\u0026ndash;75 points)\u003c/b\u003e: complex non-unions requiring \u003cb\u003emajor mechanical revision plus biological therapy (M\u0026thinsp;+\u0026thinsp;b)\u003c/b\u003e or \u003cb\u003eminor mechanical revision plus biological polytherapy (m\u0026thinsp;+\u0026thinsp;B)\u003c/b\u003e.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 4 (\u0026ge;\u0026thinsp;76 points)\u003c/b\u003e: very severe non-unions with poor biological and mechanical environment; strategies include \u003cb\u003eM\u0026thinsp;+\u0026thinsp;B\u003c/b\u003e, sometimes extending to salvage procedures (arthrodesis, megaprosthesis, or even amputation).\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eThis scoring system was validated in 2014 on a 300-patient cohort[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], demonstrating strong predictive value for treatment planning and outcome, and it is now widely cited as a structured decision-making framework in complex non-unions.\u003c/p\u003e\u003cp\u003eNevertheless, NUSS presents practical limitations. Key parameters, such as the size of the bone defect and the vascularization of osseous tissue are frequently underestimated before surgery and can only be reliably assessed intraoperatively. This can shift the score and alter the theoretically recommended strategy. Moreover, in real-world practice, many teams tend to adopt more aggressive combined mechanical and biological treatments even in lower NUSS groups, aiming to maximize union probability and shorten healing time. Whether such \u0026ldquo;overtreatment\u0026rdquo; provides superior outcomes compared with NUSS-guided algorithms remains insufficiently investigated.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStudy objective.\u003c/b\u003e Building on these considerations, the present study (i) compares preoperative versus intraoperative assessment of bone defect and examines the resultant impact on the final NUSS score and the algorithm-driven therapeutic recommendation, and (ii) evaluates our centre\u0026rsquo;s tendency to frequently combine biological stimulation with hardware revision - even in lower NUSS groups - against the outcomes reported in Calori\u0026rsquo;s validation cohort, under the hypothesis that such an approach improves union rates and accelerates healing.\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cp\u003e\u003cb\u003eStudy design and population\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWe conducted a single-centre retrospective study including 103 patients who underwent surgical management of long-bone non-union at Cliniques Universitaires Saint-Luc, Brussels, between 2015 and 2023. Ethical approval was obtained from the institutional review board (reference B403201523492). Clinical outcomes\u0026mdash;including therapeutic modalities, union rates, and time to radiological consolidation\u0026mdash;were compared with the reference cohort published by Calori et al. in 2014.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInclusion and exclusion criteria\u003c/b\u003e\u003c/p\u003e\u003cp\u003eEligible patients were adults (\u0026ge;\u0026thinsp;18 years) with non-union of a long bone, managed surgically, and with a minimum clinical follow-up of 12 months. Preoperative evaluation included complete blood count, C-reactive protein (CRP), white blood cell count, and glycated haemoglobin (HbA1c). Medication history (NSAIDs, corticosteroids) and comorbidities were systematically collected.\u003c/p\u003e\u003cp\u003eExclusion criteria were:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003epatients\u0026thinsp;\u0026lt;\u0026thinsp;18 years old,\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003emultiple non-unions,\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003enon-unions involving non-long bones (flat or short bones),\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eimmunosuppressive treatment,\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003epsychiatric disorders,\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eactive or prior malignancy, or ongoing chemotherapy.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eData collection and definitions\u003c/b\u003e\u003c/p\u003e\u003cp\u003eDemographic and clinical data included age at diagnosis, sex, body mass index (BMI), smoking status, diabetes, HIV status, anatomical site of non-union, fracture characteristics (open vs closed), initial treatment, and number of previous surgical procedures. Soft-tissue condition and need for flap coverage were also recorded.\u003c/p\u003e\u003cp\u003eNon-union was defined according to the US Food and Drug Administration (FDA): absence of healing progression for at least nine months after fracture, with no radiological evidence of consolidation during the last three months. Union was defined as bridging callus across at least three of four cortices, obliteration of the fracture line, and restoration of cortical continuity.\u003c/p\u003e\u003cp\u003eThe NUSS score was calculated preoperatively and recalculated in the immediate postoperative period after debridement, based on radiographs or CT scans. Patients were classified into NUSS therapeutic groups:\u003c/p\u003e\u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 1 (\u0026lt;\u0026thinsp;26)\u003c/b\u003e: major change of fixation system (M)\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 2 (26\u0026ndash;50)\u003c/b\u003e: minor fixation correction (m)\u0026thinsp;+\u0026thinsp;biological monotherapy (b)\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 3 (51\u0026ndash;75)\u003c/b\u003e: either major fixation\u0026thinsp;+\u0026thinsp;biological monotherapy (M\u0026thinsp;+\u0026thinsp;b), or minor fixation\u0026thinsp;+\u0026thinsp;biological polytherapy (m\u0026thinsp;+\u0026thinsp;B)\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e\u003cb\u003eGroup 4 (\u0026gt;\u0026thinsp;75)\u003c/b\u003e: salvage strategies including amputation, arthrodesis, prosthesis, or megaprosthesis.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e\u003cp\u003eTreatment modalities were recorded (single- vs two-stage procedure, with or without allograft, with or without biological adjuncts). Outcomes included union rate, time to radiological healing, complications, and reasons for surgical revision in case of failure.\u003c/p\u003e\u003cp\u003e\u003cb\u003eStatistical analysis\u003c/b\u003e\u003c/p\u003e\u003cp\u003eData were analysed using SPSS software. After NUSS scoring, patients were allocated into therapeutic groups and compared with the reference cohort of Calori et al. The significance threshold was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Union rates were compared using a binomial test for proportions, and mean healing time was analysed with a one-sample Student\u0026rsquo;s t-test.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e3.1 Patient characteristics\u003c/h2\u003e\n \u003cp\u003eThe main demographic and clinical characteristics of the cohort are summarized Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Among the 103 included patients, the majority were male (66%), and nearly 70% were overweight or obese. Approximately one-third were smokers (30.1%), a well-recognized risk factor for impaired bone healing. Diabetes was present in 8.7%, and in most cases glycaemic control was adequate (HbA1c\u0026thinsp;\u0026lt;\u0026thinsp;10% in 80% of diabetic patients), limiting its negative influence on consolidation.\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePopulation characteristics\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003ePopulation characteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMasculine\u003c/p\u003e\n \u003cp\u003eFeminine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e68\u003c/p\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e66.0\u003c/p\u003e\n \u003cp\u003e34.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLean (\u0026lt;\u0026thinsp;18.5)\u003c/p\u003e\n \u003cp\u003eNormal (18.5\u0026ndash;24.9)\u003c/p\u003e\n \u003cp\u003eOverweight (25.0\u0026ndash;29.9)\u003c/p\u003e\n \u003cp\u003eObese (\u0026gt;\u0026thinsp;30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003cp\u003e33.0\u003c/p\u003e\n \u003cp\u003e27.2\u003c/p\u003e\n \u003cp\u003e38.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSmoking\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69.9\u003c/p\u003e\n \u003cp\u003e30.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eDiabetes\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e94\u003c/p\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e91.3\u003c/p\u003e\n \u003cp\u003e8.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGlycated Hb\u003c/strong\u003e (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;10%\u003c/p\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;10%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e93\u003c/p\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90.3\u003c/p\u003e\n \u003cp\u003e7.8\u003c/p\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eFracture\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClosed\u003c/p\u003e\n \u003cp\u003eOpen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81\u003c/p\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78.6\u003c/p\u003e\n \u003cp\u003e21.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eInitial treatment\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eConservative\u003c/p\u003e\n \u003cp\u003eExternal fixator\u003c/p\u003e\n \u003cp\u003eInternal intramedullary fixation\u003c/p\u003e\n \u003cp\u003eExtra medullary internal fixation\u003c/p\u003e\n \u003cp\u003eInt Fix Ext Med\u0026thinsp;+\u0026thinsp;bone graft\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003cp\u003e23.3\u003c/p\u003e\n \u003cp\u003e21.4\u003c/p\u003e\n \u003cp\u003e43.7\u003c/p\u003e\n \u003cp\u003e9.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eNumber of previous surgeries\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;2\u003c/p\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;4\u003c/p\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32.0\u003c/p\u003e\n \u003cp\u003e40.8\u003c/p\u003e\n \u003cp\u003e27.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBone lesion\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHumerus\u003c/p\u003e\n \u003cp\u003eFemur\u003c/p\u003e\n \u003cp\u003eTibia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003cp\u003e44\u003c/p\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.9\u003c/p\u003e\n \u003cp\u003e42.7\u003c/p\u003e\n \u003cp\u003e54.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eInfection\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59\u003c/p\u003e\n \u003cp\u003e44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57.3\u003c/p\u003e\n \u003cp\u003e42.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eCRP (mg/L)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;20\u003c/p\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e89\u003c/p\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e86.4\u003c/p\u003e\n \u003cp\u003e13.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eWC (cells/\u0026micro;L)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;\u0026thinsp;12000\u003c/p\u003e\n \u003cp\u003e\u0026gt;\u0026thinsp;12000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e92\u003c/p\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e89.3\u003c/p\u003e\n \u003cp\u003e10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003eTotal population\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e103\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eRegarding the initial trauma, 21.4% of fractures were open, and 98% were surgically treated. The most common primary management strategy was osteosynthesis\u0026mdash;either plate fixation or intramedullary nailing\u0026mdash;in over 60% of cases. In 10% of patients, bone grafting was combined with fixation at the time of initial surgery.\u003c/p\u003e\n \u003cp\u003eThe complexity of the cohort is illustrated by the fact that 70% had undergone at least two prior surgeries before definitive non-union treatment. The tibia was the most frequently affected site (54.4%), followed by the femur (42.7%).\u003c/p\u003e\n \u003cp\u003eAt the time of surgery, 42.7% had a history of local infection, though only 13.6% showed elevated CRP (\u0026gt;\u0026thinsp;20 mg/L) and 10.7% leucocytosis, suggesting that a minority had active infection at the time of intervention.\u003c/p\u003e\n \u003cp\u003eThe mean follow-up was 34 months. Non-consolidation with the need for further surgery occurred in 18 patients (17%), mainly due to persistent infection (n\u0026thinsp;=\u0026thinsp;9) or refracture on persistent non-union with implant failure (n\u0026thinsp;=\u0026thinsp;3).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n \u003ch2\u003e3.2 Distribution according to NUSS groups\u003c/h2\u003e\n \u003cp\u003eThe distribution of patients according to NUSS classification is shown in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. Most patients belonged to group 2 (44.7%) or group 1 (32.0%), while group 3 accounted for 23.3%. No patients were classified in group 4.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eSeparation of the population into the different NUSS groups ; The postoperative score was obtained after measurement of the bone defect after debridement\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eNUSS SCORE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePre-op\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePost-op\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMax\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMin\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStDev\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMax\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMin\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStDev\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 0\u0026ndash;25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e44.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.90\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 26\u0026ndash;50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e58.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.86\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 51\u0026ndash;75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 76\u0026ndash;100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eIn group 1, mean NUSS scores remained stable between pre- and postoperative assessments (19.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.7, p\u0026thinsp;=\u0026thinsp;0.180). In group 2, scores showed a small, non-significant increase (36.3 \u0026rarr; 37.4, p\u0026thinsp;=\u0026thinsp;0.513). In contrast, group 3 demonstrated a statistically significant increase in mean NUSS score (58.8 \u0026rarr; 59.5, p\u0026thinsp;=\u0026thinsp;0.00027), suggesting either more precise intraoperative reassessment or a genuine increase in defect size after radical debridement.\u003c/p\u003e\n \u003cp\u003eTable 3 highlights the distribution of risk factors across NUSS groups. Notably, infection was present in 96% of group 3 patients, while smoking was most prevalent in group 3 (54%) compared with group 2 (39%) and absent in group 1.\u003c/p\u003e\n \u003ctable id=\"Tab9\" border=\"1\"\u003e\n \u003ccaption\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eDistribution of patients by group, by smoking and presence of infected non-union\u003c/div\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eGroups\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eN patients in each group\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eSmoking\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e%\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003eInfection\u003c/div\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e%\u003c/div\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e1\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e33\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e0%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e2\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e6%\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e2\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e46\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e18\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e39%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e19\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e41%\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003e3\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e24\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e13\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e54%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e23\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e96%\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e\u003cspan class=\"Bold\"\u003eN total patients\u003c/span\u003e\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e103\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e31\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e30%\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e44\u003c/div\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cdiv class=\"SimplePara\"\u003e43%\u003c/div\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n \u003ch2\u003e3.3 Bone defect analysis\u003c/h2\u003e\n \u003cp\u003ePre- and postoperative bone defect measurements are detailed in Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. A general trend toward larger postoperative defects was observed.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePre- and post-operative bone defect (cm)\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eBone defect size (cm)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePre-op\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"5\"\u003e\n \u003cp\u003ePost-op\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMax\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMin\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStDev\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMedian\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMax\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eMin\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eStDev\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e32.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.39\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 0\u0026ndash;25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e44.7%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.60\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 26\u0026ndash;50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 51\u0026ndash;75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 4\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS 76\u0026ndash;100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 1, mean defect size increased slightly (0.5 \u0026rarr; 0.7 cm, p\u0026thinsp;=\u0026thinsp;0.180, Wilcoxon test).\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 2, mean defect size increased from 1.3 to 2.8 cm (p\u0026thinsp;=\u0026thinsp;0.513, Wilcoxon test).\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 3, the difference was statistically significant, with mean bone loss increasing from 7.2 to 10.5 cm (p\u0026thinsp;=\u0026thinsp;0.00027, paired t-test).\u003c/p\u003e\n \u003c/li\u003e\n \u003c/ul\u003e\n \u003cp\u003eOverall, 18 patients (17.5%) experienced a change in their NUSS score between pre- and postoperative assessments, and 2 patients (1.9% of the total cohort) were reclassified into a higher NUSS group (group 2 \u0026rarr; group 3) (Table \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e ; Graphic 1).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab5\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePostoperative NUSS score change\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eHow many have had a change in NUSS score pre and post?\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eHow many have changed NUSS groups?\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.1%\u003c/p\u003e\n \u003cp\u003e(ou 1.9% total pop)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003e3.4 Overtreatment\u003c/h2\u003e\n \u003cp\u003eComparison of actual treatments with those recommended by the NUSS protocol revealed a strong tendency toward overtreatment (Table \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab6\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003e% overtreatment for each group: M\u0026thinsp;=\u0026thinsp;complete change in fixation system / m\u0026thinsp;=\u0026thinsp;minor change in fixation system / b\u0026thinsp;=\u0026thinsp;monotherapy biologic therapy / B\u0026thinsp;=\u0026thinsp;biologic combination therapy; treatment in bold type\u0026thinsp;=\u0026thinsp;treatment that corresponds to the NUSS protocol OR under treatment\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"7\"\u003e\n \u003cp\u003eGroup 1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNUSS Protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTreatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e% overtreatment\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003eM\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003em\u0026thinsp;+\u0026thinsp;b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003e93.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u0026thinsp;+\u0026thinsp;b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003em\u0026thinsp;+\u0026thinsp;B\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u0026thinsp;+\u0026thinsp;B\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eM\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003eTotal\u003c/em\u003e:\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e33\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003em\u0026thinsp;+\u0026thinsp;b\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eM\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"6\"\u003e\n \u003cp\u003e87.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003em\u0026thinsp;+\u0026thinsp;b\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u0026thinsp;+\u0026thinsp;b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003em\u0026thinsp;+\u0026thinsp;B\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eM\u0026thinsp;+\u0026thinsp;B\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003eTotal\u003c/em\u003e:\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e46\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"5\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eM\u0026thinsp;+\u0026thinsp;b\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003em\u0026thinsp;+\u0026thinsp;B\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" rowspan=\"5\"\u003e\n \u003cp\u003e12.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"3\"\u003e\n \u003cp\u003e\u003cstrong\u003eM\u0026thinsp;+\u0026thinsp;B\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eM\u0026thinsp;+\u0026thinsp;B\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMegaproth\u0026egrave;se\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eArthrod\u0026egrave;se\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003eTotal\u003c/em\u003e:\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003e24\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\u003cspan\u003e\n \u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eIn \u003cstrong\u003egroup 1\u003c/strong\u003e, \u003cstrong\u003e93.9%\u003c/strong\u003e of patients received more intensive treatment than recommended, most commonly combining mechanical revision with biological stimulation.\u003c/p\u003e\n \u003c/li\u003e\n \u003c/ul\u003e\n \u003c/span\u003e\u003cspan\u003e\n \u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eIn \u003cstrong\u003egroup 2\u003c/strong\u003e, the overtreatment rate was \u003cstrong\u003e87.0%\u003c/strong\u003e, with frequent use of major fixation changes or biological polytherapy.\u003c/p\u003e\n \u003c/li\u003e\n \u003c/ul\u003e\n \u003c/span\u003e\u003cspan\u003e\n \u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eIn \u003cstrong\u003egroup 3\u003c/strong\u003e, overtreatment was limited to \u003cstrong\u003e12.5%\u003c/strong\u003e, as most patients received treatment aligned with protocol recommendations. Only a few underwent salvage strategies such as arthrodesis or megaprosthesis implantation.\u003c/p\u003e\n \u003c/li\u003e\n \u003c/ul\u003e\n \u003c/span\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003e3.5 Union rates\u003c/h2\u003e\n \u003cp\u003eUnion rates for our cohort and for Calori\u0026rsquo;s reference series are presented in Table \u003cspan class=\"InternalRef\"\u003e7\u003c/span\u003e. The overall consolidation rate in our population was 83.0%, closely comparable to the 85.5% reported by Calori et al. This similarity suggests that our treatment strategy\u0026mdash;despite a high frequency of overtreatment relative to NUSS recommendations\u0026mdash;achieved outcomes consistent with those of the reference cohort.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab7\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eHealing rate (%)\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eHealing rate\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNUSS\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCalori et al.\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTreatment\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e86.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e97.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.058\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e87.1%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e78.3%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.065\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e82.1%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e73.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.123\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGlobal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e85.5%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e83.0%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eWhen stratified by NUSS subgroup, important differences emerge.\u003c/p\u003e\n \u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 1 (NUSS\u0026thinsp;\u0026le;\u0026thinsp;25), union was achieved in 97.0% of patients, which is notably higher than the 86.9% reported by Calori. This difference approached statistical significance (p\u0026thinsp;=\u0026thinsp;0.058). While not formally significant, the trend strongly suggests that the systematic addition of biological stimulation in our series may have contributed to superior outcomes in this subgroup. Clinically, this translates to a very low risk of persistence of non-union in \u0026ldquo;simple\u0026rdquo; cases when treated more aggressively.\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 2 (NUSS 26\u0026ndash;50), our consolidation rate was 78.3%, lower than the 87.1% in Calori\u0026rsquo;s study, though again without statistical significance (p\u0026thinsp;=\u0026thinsp;0.065). This finding is somewhat counterintuitive given our frequent overtreatment in this group (87%). One likely explanation is the high prevalence of infection (41%) and smoking (39%) in our group 2 patients\u0026mdash;factors well recognized to impair bone healing and not fully accounted for in the NUSS algorithm.\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 3 (NUSS 51\u0026ndash;75), our union rate was 73.9% compared to 82.1% in Calori (p\u0026thinsp;=\u0026thinsp;0.123). Although not statistically significant, the lower rate highlights the inherent complexity of managing biologically and mechanically compromised non-unions, where systemic and local factors (chronic infection, vascularity, quality of soft tissues) may dominate outcomes regardless of the treatment strategy.\u003c/p\u003e\n \u003c/li\u003e\n \u003c/ul\u003e\n \u003cp\u003eOverall, while our global results are comparable to those of Calori, the subgroup analysis emphasizes that overtreatment appears most beneficial in group 1 non-unions, but less impactful in more complex cases where biological and systemic risk factors prevail.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003e3.6 Time to consolidation\u003c/h2\u003e\n \u003cp\u003eRadiological consolidation times are shown in Table \u003cspan class=\"InternalRef\"\u003e8\u003c/span\u003e.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\n \u003ctable id=\"Tab8\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRadiological consolidation (in months)\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colspan=\"4\"\u003e\n \u003cp\u003eRadiological consolidation (in months)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eNUSS\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCalori et al.\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTreatment\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ep value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e1\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.8 +- 2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.8+-1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.04\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.0+- 1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.7+-1.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.291\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003e3\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.5+-1.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.2+-1.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cul\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 1, the mean time to consolidation was significantly shorter in our series (7.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 months) than in Calori\u0026rsquo;s (8.8\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 months, p\u0026thinsp;=\u0026thinsp;0.04). This reduction of approximately one month is both statistically significant and clinically relevant. Earlier union in this group may be attributed to the systematic use of biological adjuncts (e.g., bone marrow aspirate concentrate combined with demineralized bone matrix), which are simple, minimally invasive, and without significant morbidity. From a clinical standpoint, this shortened healing time can lead to faster weight-bearing, earlier rehabilitation, and improved patient quality of life.\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 2, consolidation occurred in 8.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3 months versus 9.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 months in Calori (p\u0026thinsp;=\u0026thinsp;0.291). Although numerically shorter, the difference was not statistically significant. This suggests that, despite frequent overtreatment, the biological and systemic risk profile of these patients may have limited the effectiveness of additional interventions.\u003c/p\u003e\n \u003c/li\u003e\n \u003cli\u003e\n \u003cp\u003eIn group 3, consolidation required 10.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 months in our cohort, compared with 9.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 months in Calori (p\u0026thinsp;=\u0026thinsp;0.064). Although the difference did not reach significance, the trend toward longer healing times underscores the difficulty of achieving rapid consolidation in severe cases, where bone defect size, poor vascularity, and infection are dominant limiting factors.\u003c/p\u003e\n \u003c/li\u003e\n \u003c/ul\u003e\n \u003cp\u003eTaken together, these findings suggest that overtreatment is particularly effective in reducing healing times in group 1 non-unions, but less so in groups 2 and 3, where systemic and biological risk factors exert a stronger influence.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\n \u003ch2\u003e3.7 Success rates by treatment intensity\u003c/h2\u003e\n \u003cp\u003eAs illustrated in Graphic 2, no failures were reported in patients who were undertreated relative to NUSS recommendations. Among patients treated according to protocol, the success rate was 78%, while those receiving more intensive treatment achieved a higher success rate of approximately 85%.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe Non-Union Scoring System (NUSS) represents, to our knowledge, the first comprehensive classification system for non-unions to adopt a truly integrative approach, combining clinical, biological, radiological, and mechanical parameters in order to guide personalized treatment strategies. Its philosophy is consistent with the principles of evidence-based medicine: relying on objective, reproducible criteria while maintaining a pragmatic orientation, namely to provide clinicians with therapeutic recommendations adapted to the individual patient and to the specific complexity of the non-union.\u003c/p\u003e\n\u003cp\u003eCompared with earlier classifications, which were often limited to purely radiological or anatomical features (e.g. Weber and Cech), NUSS distinguishes itself by its breadth and granularity. The system explicitly incorporates systemic risk factors\u0026mdash;including age, comorbidities, smoking, and infection\u0026mdash;and assigns them differentiated weights based on their presumed impact on healing potential. This weighted approach is coherent with extensive literature documenting, for example, the inhibitory role of smoking on osteogenesis[\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e]. Perhaps most importantly, NUSS links its classification to a structured therapeutic ladder, ranging from relatively conservative revision of fixation in simple cases to complex mechanical and biological reconstruction, and extending to salvage options such as megaprosthesis or amputation in the most severe scenarios. In this way, NUSS provides a structured framework for standardization while also accommodating inter-patient variability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ea) Preoperative versus intraoperative assessment of bone defects\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOur first hypothesis was that discrepancies between preoperative and intraoperative bone defect assessments might shift patient classification and alter the corresponding treatment recommendation. Indeed, our data confirmed a \u003cstrong\u003esystematic trend toward larger bone defects postoperatively\u003c/strong\u003e, most pronounced in group 3 patients. This can be explained by the more extensive debridement typically required in complex cases, which exposes viable bone ends at the cost of enlarging the defect, as well as by the limited sensitivity of preoperative imaging in distinguishing viable from necrotic or sclerotic bone.\u003c/p\u003e\n\u003cp\u003eAlthough \u003cstrong\u003e17.5% of patients\u003c/strong\u003e experienced a change in their NUSS score between pre- and postoperative assessments, only \u003cstrong\u003e2 patients (1.9%)\u003c/strong\u003e were reclassified into a higher therapeutic group. This low reclassification rate supports the overall robustness of preoperative NUSS scoring as a surgical planning tool. However, in these two cases, treatment escalation (from minor mechanical revision with biological monotherapy to major revision with biological polytherapy) was indeed warranted\u0026mdash;and both patients achieved successful union. Importantly, the strategy adopted by our team was consistent with group 3 recommendations, even though preoperative scoring had placed them in group 2. These findings underscore that \u003cstrong\u003erigid adherence to NUSS may underestimate therapeutic needs in selected cases\u003c/strong\u003e, reinforcing the importance of intraoperative reassessment and clinical judgment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eb) Clinical practice and overtreatment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOur second hypothesis concerned the gap between NUSS recommendations and our institutional practice. We anticipated\u0026mdash;and confirmed\u0026mdash;a systematic tendency toward \u003cstrong\u003eovertreatment\u003c/strong\u003e, particularly in lower NUSS categories. In group 1, 94% of patients received more intensive treatment than recommended, typically involving both mechanical revision and biological stimulation. Similarly, 87% of group 2 patients were \u0026ldquo;over-treated.\u0026rdquo; By contrast, overtreatment was rare (12.5%) in group 3, where most patients received treatment aligned with protocol recommendations.\u003c/p\u003e\n\u003cp\u003eThis proactive strategy is rooted in the belief that the systematic addition of osteoinductive or osteoconductive adjuvants improves consolidation, even in apparently simple non-unions. Our results partially validate this philosophy. In group 1, our union rate reached \u003cstrong\u003e97%\u003c/strong\u003e, compared with \u003cstrong\u003e86.9%\u003c/strong\u003e in Calori\u0026rsquo;s series (p\u0026thinsp;=\u0026thinsp;0.058), suggesting a possible clinical benefit of routine biological augmentation. In group 2, however, despite frequent overtreatment, our union rate was lower (\u003cstrong\u003e78.3% vs. 87.1%\u003c/strong\u003e, p\u0026thinsp;=\u0026thinsp;0.065). This paradox may reflect the \u003cstrong\u003ehigh burden of risk factors\u003c/strong\u003e in our cohort \u0026mdash; 39% smokers and 41% with infection in group 2 alone \u0026mdash; factors strongly predictive of impaired healing. In group 3, outcomes were poorer overall, regardless of treatment intensity, underscoring the complexity of advanced non-unions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ec) Impact on time to consolidation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWith respect to bone healing time, a significant difference was observed in group 1: an average of 7.8 months with our protocol versus 8.8 months in Calori\u0026rsquo;s study. This one-month reduction is both clinically and statistically meaningful (p\u0026thinsp;=\u0026thinsp;0.04), particularly regarding functional recovery and patient quality of life. A similar, though non-significant, trend was noted in group 2, which may reflect the beneficial impact of a more aggressive treatment strategy.\u003c/p\u003e\n\u003cp\u003eThe intraoperative use of bone marrow aspirate harvested from the iliac crest, concentrated by centrifugation, and combined with demineralized bone matrix (DBM) and frozen cancellous bone\u0026mdash;as applied in several cases within our cohort\u0026mdash;proved to be a simple, minimally invasive procedure without significant morbidity. Numerous studies have documented the positive effect of this approach on bone regeneration[\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e], primarily through the contribution of mesenchymal stem cells, cytokines, and growth factors. It therefore appears reasonable to consider this technique an effective therapeutic adjuvant, even in cases of pseudarthrosis initially classified as simple.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ed) Outcomes relative to NUSS recommendations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhen analysed by treatment adherence, patients treated strictly according to NUSS recommendations achieved a success rate of 78%, while those treated more intensively reached 85%. Notably, no failures were recorded among undertreated patients, though the small sample size warrants caution in interpretation. These findings suggest that overtreatment did not compromise outcomes and may even have conferred a modest benefit, especially in group 1. However, the high prevalence of infection in our series (43%) likely tempered overall success rates.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ee) Limitations of NUSS: toward a dynamic interpretation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDespite its many strengths, the NUSS has inherent limitations. A major concern lies in the potential mismatch between the \u003cstrong\u003ebiological phenotype of the non-union\u003c/strong\u003e and its classification within the score. For example, an atrophic non-union without systemic risk factors may be scored as group 1, yet by its biological nature it clearly warrants targeted stimulation[\u003cspan class=\"CitationRef\"\u003e21\u003c/span\u003e]. This illustrates the need for a \u003cstrong\u003edynamic interpretation of NUSS\u003c/strong\u003e, integrating both the objective criteria defined by the score and the morphological, biological, and histological features of the non-union site.\u003c/p\u003e\n\u003cp\u003eUltimately, while NUSS constitutes a major step forward in standardization and therapeutic guidance, it cannot replace clinical expertise and surgical judgment. The integration of local biology, patient history, infection status, and technical feasibility of reconstructive options remains indispensable for truly personalized management.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eOur critical evaluation of the NUSS score in clinical practice confirms its value as an integrative and pragmatic tool for the assessment of non-unions, while also highlighting important limitations in real-world application. By combining clinical, mechanical, biological, and radiological parameters, NUSS represents a significant step toward personalized orthopaedic care based on reproducible criteria capable of guiding tailored treatment strategies.\u003c/p\u003e\u003cp\u003eOur study demonstrates the \u003cb\u003erobustness of preoperative NUSS scoring\u003c/b\u003e, with only 1.9% of patients reclassified into a different therapeutic group after surgery, despite notable discrepancies between preoperative imaging and intraoperative findings. This overall stability validates the score as a surgical planning tool, but also emphasizes the need for \u003cb\u003eflexible interpretation\u003c/b\u003e, particularly when intraoperative bone loss is underestimated.\u003c/p\u003e\u003cp\u003eFrom a therapeutic perspective, our cohort revealed a clear trend toward \u003cb\u003eovertreatment\u003c/b\u003e, especially in group 1 non-unions, where we systematically combined mechanical revision with biological stimulation beyond NUSS recommendations. This approach resulted in a remarkably high union rate (97%) and a significantly shorter healing time, without added morbidity. These findings suggest a real clinical benefit and support the use of \u003cb\u003eminimally invasive biological adjuvants\u003c/b\u003e (such as bone marrow aspirate combined with DBM) even in apparently simple non-unions. At the same time, they raise questions about the \u003cb\u003ecost-effectiveness\u003c/b\u003e of overtreatment, particularly in relation to its potential to reduce healing times, increase union rates, and limit the need for reoperation.\u003c/p\u003e\u003cp\u003eConversely, the less favourable outcomes observed predominantly in group 2\u0026mdash;despite the frequent use of overtreatment\u0026mdash;highlight the limitations of a uniform strategy and the multifactorial complexity of bone healing. This disparity suggests that certain determinants, particularly those of a biological or local tissue nature, are more intricate than those accounted for in the NUSS score or currently integrated into clinical practice. It therefore supports the need for an expanded model that more precisely incorporates the condition of the non-union site (e.g., vascularization, histological features, chronicity), and potentially for a future adaptation of the score to include osteoinductive signalling and the cellular microenvironment, concepts derived from the Diamond Theory.\u003c/p\u003e\u003cp\u003eUltimately, our findings highlight the importance of interpreting NUSS in a \u003cb\u003edynamic and nuanced way\u003c/b\u003e. While it provides a valuable framework for standardization and decision-making, NUSS should be regarded as a \u003cb\u003eflexible guide\u003c/b\u003e, to be enriched by clinical expertise, biological characteristics of the non-union, and the technical feasibility of reconstructive options. Within this perspective, the rational use of biological augmentation\u0026mdash;even in simple cases\u0026mdash;appears justified when the objective is to optimize both union rate and healing time.\u003c/p\u003e\u003cp\u003eThe \u003cb\u003efuture of non-union management\u003c/b\u003e likely lies in bridging classification tools such as NUSS with biological and molecular models, leading to \u003cb\u003epersonalized treatment protocols\u003c/b\u003e that integrate clinical, mechanical, and biological parameters. This approach will help standardize best practices while optimizing functional outcomes within an evidence-based framework.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eStudy design: DSRD and OC.\u003c/p\u003e\n\u003cp\u003eData collection/validation: DSRD and BPA.\u003c/p\u003e\n\u003cp\u003eData analysis: MJ.\u003c/p\u003e\n\u003cp\u003eResult interpretation: DSRD and OC.\u003c/p\u003e\n\u003cp\u003eReporting and editing: DSRD.\u003c/p\u003e\n\u003cp\u003eProject guarantor: DSRD and OC. The authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eData will be available upon request by the first author DSRD.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eEthical approval was obtained from the Ethics Committee under reference number B403201523492.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBrinker MR, O\u0026rsquo;Connor DP. Nonunions: evaluation and treatment. In: Bucholz RW, Heckman JD, Court-Brown CM, Tornetta P, editors. Rockwood and Green\u0026rsquo;s Fractures in Adults. 10th ed. Philadelphia: Lippincott Williams \u0026amp; Wilkins; 2022.\u003c/li\u003e\n\u003cli\u003eCalori GM, Albisetti W, Agus A, et al. Risk factors contributing to fracture non-unions. Injury. 2007;38 (Suppl ): SS11\u0026ndash;8. doi: 10.1016/S0020-1383(07)80004-0.\u003c/li\u003e\n\u003cli\u003eHak DJ, Fitzpatrick D, Bishop JA, et al. Delayed union and nonunions: epidemiology, clinical issues, and financial aspects. Injury. 2014;45(Suppl 2):S3\u0026ndash;7. doi: 10.1016/j.injury.2014.04.002.\u003c/li\u003e\n\u003cli\u003eTzioupis C, Giannoudis PV. Prevalence of long-bone non-unions. Injury. 2007;38(Suppl 2):S3\u0026ndash;9. doi: 10.1016/s0020-1383(07)80003-9.\u003c/li\u003e\n\u003cli\u003eFoster AL, Moriarty TF, Trampuz A, et al. Fracture-related infection: current methods for prevention and treatment. Expert Rev Anti Infect Ther. 2020 Apr;18(4):307-321. doi: 10.1080/14787210.2020.1729740\u003c/li\u003e\n\u003cli\u003eCalori GM, Mazza E, Colombo M, et al. The use of bone-graft substitutes in large bone defects: any specific needs? Injury. 2011;42(Suppl 2):S56\u0026ndash;63. doi: 10.1016/j.injury.2011.06.011.\u003c/li\u003e\n\u003cli\u003eWittauer M, Burch MA, McNally M, et al. Definition of long-bone nonunion: A scoping review of prospective clinical trials to evaluate current practice. Injury. 2021 Nov;52(11):3200-3205. doi: 10.1016/j.injury.2021.09.008.\u003c/li\u003e\n\u003cli\u003eZura R, Mehta S, Della Rocca GJ, et al. Biological risk factors for nonunion of bone fracture. JBJS Rev. 2016;4(1):01874474. doi: 10.2106/JBJS.RVW.O.00008.\u003c/li\u003e\n\u003cli\u003ePatel RA, Wilson RF, Patel PA, et al. The effect of smoking on bone healing: a systematic review. Bone Joint Res. 2013;2(6):102\u0026ndash;111. doi: 10.1302/2046-3758.26.2000142.\u003c/li\u003e\n\u003cli\u003eJensen SS, Jensen NM, Gundtoft PH, et al. Risk factors for nonunion following surgically managed, traumatic, diaphyseal fractures: a systematic review and meta-analysis. EFORT Open Rev. 2022 Jul 5;7(7):516-525. doi: 10.1530/EOR-21-0137.\u003c/li\u003e\n\u003cli\u003ePerren SM. Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation. Clin Orthop Relat Res. 2002;(398):7\u0026ndash;24. doi: 10.1302/0301-620x.84b8.13752.\u003c/li\u003e\n\u003cli\u003eWeber BG, Oldrich C, Konstam PG. Bern: Hans Huber Publishers; 1976. Pseudarthrosis: Pathophysiology, biomechanics, therapy, results; p. 323.\u003c/li\u003e\n\u003cli\u003eReed AAC, Joyner CJ, Brownlow HC, et al. Human atrophic fracture non-unions are not avascular. Journal of Orthopaedic Research. 2002;20(3):593\u0026ndash;599. doi: 10.1016/S0736-0266(01)00142-5.\u003c/li\u003e\n\u003cli\u003eBrownlow HC, Reed A, Simpson AHRW. The vascularity of atrophic non-unions. Injury. 2002;33(2):145\u0026ndash;150. doi: 10.1016/s0020-1383(01)00153-x.\u003c/li\u003e\n\u003cli\u003eGiannoudis PV, Einhorn TA, Marsh D. Fracture healing: the diamond concept. Injury. 2007;38(Suppl 4):S3\u0026ndash;S6. doi: 10.1016/s0020-1383(08)70003-2.\u003c/li\u003e\n\u003cli\u003eCalori GM, Phillips M, Jeetle S, et al. Classification of non-union: need for a new scoring system? Injury. 2008;39(Suppl 2):S59\u0026ndash;63. doi: 10.1016/S0020-1383(08)70016-0.\u003c/li\u003e\n\u003cli\u003eCalori GM, Colombo M, Mazza EL, et al. Validation of the Non-Union Scoring System in 300 long bone non-unions. Injury. 2014 Dec;45 Suppl 6:S93-7. doi: 10.1016/j.injury.2014.10.030.\u003c/li\u003e\n\u003cli\u003eBydon M, De la Garza-Ramos R, Abt NB, et al. Impact of smoking on complication and pseudarthrosis rates after single- and 2-level posterolateral fusion of the lumbar spine. Spine (Phila Pa 1976). 2014 Oct 1;39(21):1765-70. doi: 10.1097/BRS.0000000000000527.\u003c/li\u003e\n\u003cli\u003eImpieri L, Pezzi A, Hadad H, et al. Orthobiologics in delayed union and non-union of adult long bones fractures: A systematic review. Bone Rep. 2024 Apr 6;21:101760. doi: 10.1016/j.bonr.2024.101760.\u003c/li\u003e\n\u003cli\u003eKaspiris A, Hadjimichael AC, Vasiliadis ES, et al. Therapeutic Efficacy and Safety of Osteoinductive Factors and Cellular Therapies for Long Bone Fractures and Non-Unions: A Meta-Analysis and Systematic Review. J Clin Med. 2022 Jul 4;11(13):3901. doi: 10.3390/jcm11133901.\u003c/li\u003e\n\u003cli\u003eYang, J., Zhang, X., Liang, W. et al. Efficacy of adjuvant treatment for fracture nonunion/delayed union: a network meta-analysis of randomized controlled trials. BMC Musculoskelet Disord 23, 481 (2022). doi:10.1186/s12891-022-05407-5.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Graphic","content":"\u003cp\u003eGraphic 1 and 2 are available in the Supplementary Files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"non-union, pseudarthrosis, NUSS score, bone defect, biological augmentation, fracture healing","lastPublishedDoi":"10.21203/rs.3.rs-7611992/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7611992/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003cbr\u003e\n The Non-Union Scoring System (NUSS) is the first multidimensional tool to guide treatment of fracture non-unions, but key parameters—particularly bone loss—may be underestimated preoperatively. We assessed (i) how intraoperative reassessment modifies NUSS scoring and algorithmic recommendations and (ii) whether our centre’s frequent use of combined mechanical and biological strategies (“overtreatment”) affects outcomes versus the Calori validation cohort.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003cbr\u003e\n We retrospectively reviewed 103 adults surgically treated for long-bone non-union at Cliniques Universitaires Saint-Luc (Brussels) from 2015–2023 with ≥12-month follow-up. NUSS was calculated preoperatively and recalculated immediately post-debridement from radiographs/CT; patients were stratified into NUSS therapeutic groups and compared with Calori et al. (2014). Outcomes were union, time to radiographic consolidation, and complications, analysed with binomial and Student’s \u003cem\u003et\u003c/em\u003e-tests (α=0.05).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003cbr\u003e\nThe tibia was the most affected site (54.4%), with high prevalence of infection (42.7%) and repeated surgery (≥2 procedures in 70%). Intraoperative reassessment revealed significantly larger bone defects, especially in group 3 (7.2 → 10.5 cm, p \u0026lt; 0.001), leading to NUSS score changes in 18 patients (17.5%), with reclassification in 2 cases (1.9%). In comparison with NUSS recommendations, overtreatment occurred frequently (94% in group 1, 87% in group 2), attributable to the recurrent, albeit non-systematic, use of biological stimulation. The overall union rate in our series was 83.0%, comparable to 85.5% in Calori’s cohort. Group 1 patients achieved higher union rates (97.0% vs. 86.9%, p = 0.058) and significantly shorter healing times (7.8 ± 1.6 vs. 8.8 ± 2.0 months, p = 0.04). No significant differences were found in groups 2 and 3, where outcomes were negatively influenced by infection and smoking.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003cbr\u003e\nThe NUSS provides a robust framework for classification and treatment planning in non-unions, but intraoperative reassessment is essential to avoid underestimation of bone loss. Proactive addition of biological augmentation to mechanical revision achieved very high union and shorter healing in simple non-unions without added morbidity; benefits were less evident in complex cases, where infection and adverse biology predominate. NUSS should therefore be applied as a flexible guide, complemented by clinical judgment and tailored biological strategies.\u003c/p\u003e","manuscriptTitle":"Flexible Use of the NUSS in Non-Union Surgery: Value of Intraoperative Bone Loss Assessment and Overtreatment","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-17 09:12:32","doi":"10.21203/rs.3.rs-7611992/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"962622ad-a302-4d30-8877-2ea1ba21bde9","owner":[],"postedDate":"September 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-20T07:53:21+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-17 09:12:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7611992","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7611992","identity":"rs-7611992","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}