Mid-term Functional Outcomes and Complications rates in Knee Megaprosthesis for Non-Oncologic limb Salvage Surgeries: A Comprehensive Analysis

Mid-term Functional Outcomes and Complications rates in Knee Megaprosthesis for Non-Oncologic limb Salvage Surgeries: A Comprehensive Analysis | 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 Research Article Mid-term Functional Outcomes and Complications rates in Knee Megaprosthesis for Non-Oncologic limb Salvage Surgeries: A Comprehensive Analysis Ezequiel Ortiz, Julian Costantini, matias costa paz, Lisandro Carbo This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7130371/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Purpose To retrospectively evaluate the clinical and radiological outcomes of revision total knee arthroplasty using knee megaprosthesis in patients with severe bone loss from non-oncologic causes. Methods Between 2008–2020 forty patients were evaluated with 33 month mean follow up (interquartile range: 28–61) and 72-year median age (IQR: 65–77). Radiographic analysis and a functional outcomes were carried out in the preoperative and at the final follow-up using Oxford Knee Score (OKS), Knee Society Score (KSS), Visual Analogue Pain Scale (VAS) and Musculoskeletal Tumor Society Score (MSTS). Complications were classified according to the Henderson classification system. Results Three different implant systems were used: Endo-Model® M Link in 21 cases, OSS™ Orthopedic Salvage System Zimmer Biomet in 18 cases, and the MDT prosthesis in one case. Indications were: 57% (24) prosthetic joint infection (PJI), 15% (6) aseptic loosening, 15% (6) severe osteomyelitis, 5% (2) fractures, 2.5% (1) femoral stem rupture and 2.5% (1) instability. The survival rate at 50 months was 52% (95% CI: 35% − 67%). Postoperative median MSTS score was 16 points (10–25), KSS objective: 73 (67–78), satisfaction: 30 (20–39), expectation: 12 (6–15), functional: 60 (34–70), VAS: 3 (0–8), and OKS: 24 (14–38). Clinical improvement (MCID) was assessed in 22% (9) for functional KSS, and 17% (7) for objective KSS. Twelve out of forty (30%) had positive postoperative cultures and complication occurred in 55% of the series. According to Hendersons classification: 36.4% (8) were aseptic loosening, PJI 31.8 (7), soft tissue failure 22.7% (5) and structural failures 9.1% (2). Conclusion The utilization of knee megaprosthesis in severe bone stock deficiency is a good option for limb salvage surgeries with an acceptable mid-term outcomes. Level of evidence IV Knee Megaprosthesis non oncologic reconstruction Bone defects Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Although aseptic loosening remains one of the leading causes of revision total knee arthroplasty (24–27%), revision procedures are often complicated by substantial bone loss resulting from diverse etiologies such as periprosthetic joint infection, osteolysis, component migration, periprosthetic fractures, and iatrogenic damage during implant removal [ 1 ]. Different techniques have been developed and refined for the treatment of these massive femoral and tibial bone defects such as cementation, augmentation modules, impacted bone grafts (autologous/heterologous), structural bone grafts, porous titanium or tantalum cones for isolated femur and tibia or in combination with cemented or uncemented stems, customized cones, and knee megaprosthesis [ 2 – 7 ]. One of the main challenges during revision surgery is achieving secure implant fixation, especially in cases of severely compromised bone stock, which may extend to segmental deficiencies of up to 10 cm in length [ 8 , 9 ]. Generally, the management of bone defects is guided by the location, extent, and quality of the remaining bone. The gold standard for ensuring implant fixation involves achieving stability in at least two of the three areas, as described by the principles of Jones et al. [ 2 , 8 , 9 ] Over the past thirty years, in the pursuit of limb-salvage surgeries, megaprosthesis have played a prominent role due to the benefits in terms of restoring limb length, promoting early patient mobilization with early loading and rapid implant fixation [ 10 ]. Indications for knee megaprosthesis have been expanded to non-oncologic prosthetic revisions with extensive bone loss, poor bone quality in distal femoral comminuted fracture in elder patients, pseudoarthrosis or malunions [ 3 ]. The modularity of these implants and the various degrees of constraint allow the surgeon to make modifications regarding the amount of bone stock to be resected and/or increase the degree of constraint in cases of ligament insufficiency during prosthetic revision [ 11 ]. While the goal of megaprosthesis is to restore patient mobility and limb function, thereby improving the quality of life for these patients, they are not exempt from various complications that may jeopardize the goal of limb salvage [ 12 ]. Among the most frequent complications are PJI (5–40%), aseptic loosening (4–27%), soft tissue failure (11%), periprosthetic fractures (10%), and implant rupture (2–4%), with proximal tibial rupture being the most common cause [ 11 , 13 – 15 ]. The study hypothesizes that the use of knee megaprosthesis in selected patients leads to favorable mid-term functional outcomes. The aim is to retrospectively evaluate the quality of life and clinical function in patients who underwent prosthetic revision with knee megaprosthesis due to massive non-oncologic bone defects. Materials and Methods A single-center, observational, retrospective, and descriptive study was conducted. The corresponding protocol received approval from the institutional ethics committee, adhering to the principles of the Declaration of Helsinki (n: #6048). All patients provided signed informed consent for the respective investigation. Database was collected from electronic medical records, and patient follow-up was conducted through telephone and telemedicine. Study Group : Between 2008 and 2016, an average of 45 knee prosthetic revisions were performed annually by the Knee division at our institution. An average of 4 megaprosthesis per year (range 2–6) were used. A total of 45 megaprosthesis were recorded, 5 were excluded due to lack of follow-up (Fig. 1 ). The following information was recorded: demographic data, initial diagnosis, date of surgery, implant used, stages of treatment, complications, failures rates, clinical outcomes and imaging status with x-ray. Inclusion criteria were patients with medial or lateral ligament insufficiency, bone defects affecting collateral ligament insertions, traumatic sequelae of the distal femur with ligament insufficiency, instability in revision arthroplasty, revision TKA (aseptic and septic causes), and a minimum follow-up of more than 2 years. Exclusion criteria were patients with oncologic resections involving the distal femur and proximal tibia for any cause. Failure was defined as the need for either complete or partial ¿revision for any reasons and poor to bad results with a fixed implant at the time of evaluation. Poor to bad results were defined as a summatory of a functional Knee Society Score (KSS) of less than 30, an Oxford Knee Score (OKS) of less than 19 points, and a Musculoskeletal Tumor Society Score (MSTS) of less than 9 points at time of evaluation. Failures were classified as mechanical and non-mechanical alterations. Mechanical failures included septic/ aseptic loosening, periprosthetic fractures, and/or implant ruptures. Non-mechanical failures (soft tissue defects) include extensor mechanism rupture, prolene mesh rupture, extensor mechanism revision, active fistulas, and soft tissue coverage deficits. Massive bone defects were classified according to the AORI system and measured intraoperatively in centimeters. Surgical Technique : All procedures were performed by trained surgeons. Spinal or general anesthesia was administered based on anesthesia indications. All approaches were made through a medial parapatellar approach without a tourniquet and routine tranexamic acid was administered preoperatively. Extensible approaches, quadriceps snip, or TAT osteotomy were performed as needed. In cases with extensor mechanism injury, reconstruction was performed using allografts or reconstruction with polypropylene mesh. Single-stage implantation was indicated for patients with comminuted fractures of the distal femur, massive bone stock deficit in complex revisions and periprosthetic fractures. (Fig. 2 ), (Fig. 3 a, 3 b) Postoperative Rehabilitation : All patients followed the same rehabilitation protocol, with partial weight-bearing at 24 hours postoperatively. During hospitalization, passive flexion-extension exercises were prescribed, with restricted range of motion (ROM) in patients who underwent extensor mechanism reconstruction and in patients who received a flap for soft tissue coverage. Scar healing and proper flap vascularization were monitored before authorizing knee mobility. Clinical and Imaging Evaluation : Radiographic signs of loosening were classified by type and anatomical location (femoral, tibial, or combined) (Fig. 4 ). Serial imaging was conducted during follow-up using standardized anteroposterior and lateral knee radiographs, along with scanograms. Functional outcomes were assessed using the validated Spanish versions of the Oxford Knee Score (OKS), the Musculoskeletal Tumor Society Score (MSTS), the Knee Society Score (KSS), and the Visual Analog Scale (VAS) for pain. Clinical results were considered poor or very poor when the combination of a functional KSS < 30, OKS < 19, and MSTS < 9 was present. Complications were reported and classified using the Henderson classification, which includes: 1- Soft tissue failures (instability, tendon rupture, and wound dehiscence), 2- aseptic loosening (determined clinically and radiologically), 3- structural failures (periprosthetic fractures), and 4- infections (requiring component removal and spacer placement). A Kaplan-Meier analysis was performed for implant survival, with an end point determined by any of the following events occurring first: death, amputation, revision with mega spacer or arthrodesis. Statistical Analysis: Descriptive analysis of variables was conducted, reporting continuous variables as mean and standard deviation or median interquartile range depending on distribution, and categorical variables as n (number of events) and their respective proportions. Continuous variables were compared using t-tests or Mann-Whitney tests depending on normal distribution, and categorical variables were compared using chi-square or Fisher's exact test as appropriate. To analyze whether Henderson scale values were associated with functional KSS, a linear regression model was conducted, with the functional KSS as the dependent variable and Henderson scale categories as the independent variable. Stata 14 software was used for analysis, and statistical significance was considered at P = 0.05. Results Forty patients out of forty-five fulfilled the inclusion and exclusion criteria and were included in the final analysis. Demographic data, baseline diagnosis, and surgical history are summarized in Table 1 . Table 1 Demographics. Abbreviations: Y: years, M: months, n: total number of patients. IQR: Interquartile Range. Avg: average. Results (N = 40) Age –years, median (IQR) 72 (65–77) Men, n (%) 20 (50) Follow Up (m) (RIQ) 33 (28–61) Period (y) 2008–2020 Number of previous surgeries (avg) 2 (1–9) Utilization n(%) - Prosthetic revision post-infection - Aseptic loosening - Severe osteomyelitis - Periprosthetic fractures - Stem rupture - Severe Valgus (Poliomielitis) 24 (57) 6 (15) 6 (15) 2 (5) 1 (2.5) 1 (2.5) Implant n (%) - Endo-Model® M Link - OSS™ Orthopedic Salvage System Zimmer - Endoprótesis MDT IOT Osteolife 21 (54) 18 (43) 1 (3) Bone defect (cm) - Fémur - Tibia 7.8 (1–23) 3.1 (1–13) Predominant bone defect - Fémur - Tibia - Fémur y tibia 29 10 1 Utilization of tantalum cones n (%) - Fémur y tibia - Tibia - Fémur Extensor mechanism n (%) - Reconstruction with Prolene Mesh - Extensor Apparatus Graft - Absorbs Traction 11 (27) 6 (54) 4 (36) 1 (9) 9 (22) 4 (10) 4 (10) 1 (2.5) The average number of previous surgeries before megaprosthesis implantation was 2.5 (range 1–9), with 41% of the series having undergone 2 surgeries and 39% having undergone 3 surgeries. In most cases, the diagnoses at the time of revision were septic causes in 57% (24); diagnoses at the time of revision are in Table 1 . Twenty three out of forty (57%) presented with infections at time of consultation. The most frequently preoperative pathogen was positive cocci (CC+). After megaprosthesis implantation positive cultures were detected in 12 patients (30%). But the infection rate was 15% (6 patients), the most common germen recovered was gram-negative bacilli (BGN) (Table 2 ). The standard treatment for these cases involved a two-stage procedure, including implant removal with sampling (bone and soft tissues), fixed knee mega spacer, and targeted antimicrobial therapy under infectious disease specialist supervision. Resolution of infected cases included arthrodesis in four patients, amputation in three patients, and spacer preservation in one patient at the time of the series evaluation. Table 2 Germ rescues prior to megaprosthesis implantation and post-implantation. CC +: positive cocci; CC -: negative cocci; BG -: gram-negative bacilli; BG +: gram-positive bacilli. Germs Pre- Op n= (%) Post- Op n= (%) CC + 22 (54) 2 (10) BG - 10 (24) 8 (40) CC en racimo 3 (7) 4 (20) Mycosis 3 (7) 4 (20) BG + 2 (5) 2 (10) CC - 1 (2) 0 TOTAL 41 20 Clinical and Imaging Results : Twenty-six patients (63%) have a fixed implant, while 9 (21%) presented radiolucent images in the femur and tibia indicative of aseptic loosening (2 patients in the tibia and 7 in femur and tibia). An improvement was observed for the objective and satisfaction KSS (p = 0.062 ; p = 0.423, respectively). A decrease in the KSS for expectation and function was recorded (p = 0.866 ; p = 0.545, respectively) (Fig. 5 ). The Visual Analog Pain Scale (VAS) showed a 50% decrease in the initial score. In the postoperative evolution, the median Musculoskeletal Tumor Society Score (MSTS) was 16 points (IQR: 10–25), and the Oxford Knee Score (OKS) was 24 (IQR: 14–38) (Table 3 ). Poor to bad clinical results (defined by KSS function < 30, OKS < 19, and MSTS < 9) were detected in 10% of patients (4 patients): two patients with soft tissue failure, one with aseptic loosening, and one with structural failure (periprosthetic fracture) (Table 4 ). Complications according to the Henderson classification were observed in 55% of cases (22 patients) (Table 5 ). Table 3 Clinical Outcomes. KSS Score Preoperative (RIQ) Postoperative (RIQ) Delta KSS p Value Objective 28 (27–56) 11 (67–78) 17 0.062 Satisfaction 10 (10–20) 19 (20–39) -9 0.541 Expectation 3 (9–12) 9 (6–15) -6 0.866 Functional 35 (21–56) 36 (34–70) -1 0.545 VAS 8 (8–9) 3 (0–8) 5 0.423 OKS - 24 (14–38) - - MSTS - 16 (10–25) - - Table 4 Cutoff values to considering a poor outcome according to each score. The combination of all 3 scores was reported in 10% of the series. Poor Clinical Outcomes n = 40 (%) - Postoperatoria functional KSS < 30 pts 8 (20) - OKS < 19 pts 14 (35) - MSTS < 9 pts 6 (15) - Postoperative KSS < 30, OKS < 19 and MSTS < 9 4 (10) Table 5 Complications according to Henderson´s classification. A total of 55% complications were recorded. Henderson´s Classification n(%) 1- Soft tissue Failure (unstable TKA, tendon rupture and dehiscence) 5 (22.7) 2- Aseptic Loosening 8 (36.4) 3- Structural Failure (Periprosthetic Fracture) 2 (9.1) 4- Infections (implant revision and spacer) TOTAL 7 (31.8) 22 of 40 (55) The improvement in the Minimal Clinically Important Difference (MCID) for Functional KSS is between 15 and 20 points or an improvement from 6.3 to 2 years of evolution for knee prosthetic revision surgeries according to different publications. In our series, we detected a 22% improvement (9 patients) with this clinical improvement in their evolution. For the MCID of the Objective KSS, a significant difference is an improvement of 6.6 points or a postoperative Objective KSS between 33 and 34. In our population, only 17% (7 patients) showed clinical improvement in their evolution. A linear logistic regression was performed between Henderson complications and functional KSS. When comparing the KSS of groups without complications and with postoperative complications, the latter results were worse. The group with soft tissue failure complications recorded an average 4.8 points lower than the group without complications (p = 0.748, CI: -35.999–26.245). In contrast, the group with structural failures had a KSS average of 37 times lower than the group without complications, with statistically significant differences (p = 0.046, CI: -74.273 - − .81749). The results of KSS for complications related to aseptic loosening (p = 0.360) and infections (p = 0.299) were also lower but not statistically significant. Analyzing the relationship between postoperative functional KSS and radiologically loosening, we found that the group without loosening, the functional KSS had a mean of 54.3 (SD: 24.1) with a CI of 41.202–67.545, and for the group with loosening, the functional KSS had a mean of 52 (SD: 22.6) with a CI of 36.751–67.248. The functional KSS is similar in both patient groups, with no statistically significant difference between the means and their confidence intervals. Implant Survival : The one-year survival was 80%, decreasing to 52% (95% CI: 35% − 67%) at 50 months and 21% (95% CI: 5.1% − 44%) at 100 months. Short-term survival of aseptic loosening was 100% with implant retention at the time of evaluation (Fig. 6 ). Discussion The primary outcome of this study reveals that the use of knee megaprosthesis in non-oncologic massive bone defects have a high postoperative complications rates (55%). While 22% of patients achieve the Minimal Clinically Important Difference (MCID), a significant improvement in objective KSS scores and postoperative satisfaction is observed. However, the KSS scores for expectation and function decreased, and 10% of patients experienced clinically poor to bad outcomes. These findings demonstrate favorable short-term implant survival but raise concerns about long-term longevity. A systematic review published in 2020, involving 54 patients with an average age of 75 years and an average follow-up of 43 months, demonstrated that in over half of the series (55%), the primary indication was severe bone defects following failed primary arthroplasties, aligning with our casuistry, which was 62%. The most common postoperative complication was periprosthetic infection (18%), while in our series, it was 4.8%. Implant survival was 74.8% at one year postoperatively and 40.9% at ten years. In our experience, the one-year survival rate was similar to the reported 75% [ 3 ]. The septic loosening rate in our series was 15% (6 patients), while the aseptic loosening rate was 19% (8 patients), comparable to a systematic review on non-tumor knee prosthetic revisions [ 22 ]. Some patients exhibited prosthetic loosening images that did not translate into representative functional KSS values in the postoperative period. Table 6 details a summary of publications on reconstructions with non-oncological knee megaprostheses. Table 6 Comparison of clinical studies on megaprosthesis utilization for different causes. Author n y F-up Indication (n=) Comp rates (%) Henderson classificaiton (n=) Survivorship Vaishya R (2011) (30) 10 74 (68–85) 48 Supracondilar Pseudoartrosis (10) 30 Soft Tissue Failure (2) Structural Failure (1) - Fakler JK (2013) (28) 14 77 27 Periprosthetic Fracture (6) Complex Fracture (4) Massive bone stock deficit (4) 57 Structural Failure (4) Infections (2) Soft Tissue Failure (1) Aseptic Loosening (1) - Vertesich (2019) (12) 30 75 54 Massive bone stock deficit (30) 53 Infections (8) Aseptic Loosening (4) Soft Tissue Failure (3) Structural Failure (1) 74.8% (1st year) 62.5% (3erd year) 41% (10 years) Berend & Lombardi (2009) (31) 39 76 (61–87) 24 Periprosthetic Fracture (13) Aseptic Loosening (11) Infections (11) Fractures (2) 12 Infections (3) Soft Tissue Failure(1) Aseptic Loosening(1) 87% (3erd year) Utting & Newman (2004) (32) 30 75 (61–87) 36 Periprosthetic Fracture (22) Aseptic Loosening (5) Infections (3) 26 Infections (6) Structural Failure (2) - Springer (2004) (33) 26 72 (47–92) 48 Periprosthetic Fracture (11) Aseptic Loosening (8) Fractures (5) 30 Infections (5) Structural Failure (2) Soft Tissue Failure (1) - Haidukewych (2005) (34) 17 66 (38–86) 60 Fractures (17) 35 Soft Tissue Failure(3) Aseptic Loosening(2) Infections (1) 91% (5th year). Mortazavi (2010) (35) 22 69 (54–81) 48 Periprosthetic Fracture (22) 27 Structural Failure(4) Soft Tissue Failure(1) Aseptic Loosening(1) - Smith (2013) (36) 52 68 24 Fractures (29) Infections (19) Aseptic Loosening (11) 44 Infections (13) Aseptic Loosening(5) Structural Failure(4) Soft Tissue Failure(1) - Rosen & Strauss (2004) (37) 24 76 (68–85) 12 Fractures (24) 8 Structural Failure(1) Infections (1) - Höll (2011) (29) 21 73 (53–86) 40 Fractures (14) Infections (5) Aseptic Loosening (2) 52 Infections (6) Aseptic Loosening(2) Structural Failure(2) Soft Tissue Failure(1) - Our Results (2025) 40 72 (65–77) 33 (28–61) Infections (24) Massive bone stock deficit (6) Aseptic Loosening (6) Periprosthetic Fracture (2) Stem rupture (1) 55 Aseptic Loosening (8) Infections (7) Soft Tissue Failure (5) Structural Failure (2) 52% (4th year) (IC: 35% − 67%) 21% (8th year) (IC: 5% − 44%) TOTAL (Range) 27 (10–52) 72 (66–76) 37 (12–60) Fractures (91) Periprosthetic Fracture (76) Infections (51) Aseptic Loosening (43) 35 (8–57) Infections (52) Aseptic Loosening (24) Structural Failure (22) Soft Tissue Failure (19) The use of stems during prosthetic revisions has become an almost absolute indication, with ongoing debate about cementation concerning durability and long-term survival. The primary advantage of cemented stems is their ability to fill metaphyseal defects and allow antibiotic use, while uncemented stems preserve bone stock in potential revisions [ 23 – 26 ]. Regarding fixation quality in our series, 98% (39) of patients were cemented in both stems due to massive bone stock loss; only one patient received hybrid fixation with a non-cemented femoral stem and a tibial stem cemented with a metaphyseal cone. Although we couldn't detect significant differences between both techniques due to the low casuistry in using non-cemented stems, a systematic review and meta-analysis encompassing 70 articles concluded that survival rates are comparable regardless of the evaluation period. Aseptic loosening was the most common failure in prosthetic revisions in both constructs (cemented and cementless) over medium and long-term follow-up [ 5 ]. This result aligns with our casuistry, with aseptic loosening being the primary cause of failure in 20% (8 patients). The use of metaphyseal cones aims to fill bone defects and provide an additional fixation surface for the megaprosthesis, with the primary advantage of reducing the stem length if necessary [ 8 ]. According to a systematic review and meta-analysis of 93 articles evaluating clinical and radiological outcomes of metaphyseal cones in prosthetic revision surgeries, the incidence of intraoperative fractures in patients treated with cones was 1.6% [95% CI: 0.7–3.4], a postoperative fracture risk of 4.3% [95% CI: 2.7–7], and postoperative infections at 8.5% [95% CI: 6–12] [ 27 ]. In our series, metaphyseal fixation cones were used in 26% (11 patients), primarily in AORI 3 defects; we recorded no intraoperative fractures during placement or postoperative periprosthetic fractures. Given the small sample size, we believe this reported complication was not expressed. Regarding prosthetic infections during metaphyseal cone placement, we recorded germ rescues in 45% (5 patients out of 11 in the series); two patients underwent implant extraction and spacer placement, while the rest were treated with antibiotics and implant retention. We observed no cone migrations or radiolucency images in the metaphyseal fixation zone at the time of evaluation. Considering Henderson's classification (which groups multiple complications, including soft tissue injuries), 55% of failures were recorded (23 patients). However, 20% (8 patients) subsequently underwent prosthetic revision by implant extraction. Definitive case resolution involved arthrodesis in four patients, amputation in three patients, and spacer retention in one patient at the time of evaluation. It is noteworthy that within the series, 10% of patients exhibited poor to bad outcomes despite a fixed implant at the time of evaluation. While the implant is functional, the quality of life falls short of expectations for the patient. From this, it can be inferred that 30% of the series falls into poor results and prosthetic revisions. The authors interpret this as a positive outcome considering the prior complications and bone stock deficit presented by these types of patients in the context of limb salvage surgery. Similar results were analyzed by other authors [ 12 , 28 , 29 ]. As strengths of this research, we emphasize the exclusion of patients with coexisting neoplastic pathology and the exclusivity of the series regarding the use of megaprostheses. Although the series results are satisfactory, we believe they are largely attributed to being second-time revisions without prolonged oncological treatments that may, to a greater or lesser extent, deteriorate the patient. Limitations : Our study was conducted as a single-center, retrospective, and descriptive investigation without a control group. The initial diagnoses at the time of megaprosthesis placement were diverse, such as in cases where megaprosthesis were used in two-stage revision surgeries or considered salvage procedures before opting for arthrodesis. This subset of patients, from the outset, had expectations and function markedly different from the group of patients in whom megaprosthesis indication was for severe valgus deformities, pure ligamentous instability, or massive bone defects. The heterogeneity in the patient population is another noteworthy aspect, as six patients in the series received a megaprosthesis due to secondary fungal infections following anterior cruciate ligament (ACL) reconstructions, thereby reducing the overall age mean. Conclusion Considering that 22% of the series surpassed the MCID, the rate of arthrodesis following knee megaprosthesis failure was 7.3%, with an aseptic loosening rate of 21%, a median survival of 60 months, and a 55% postoperative complication rate according to Henderson´s classification; only 20% of the series required an implant removal. These findings suggest that the utilization of knee megaprosthesis in revision surgeries with severe bone stock deficits is a viable option for limb salvage surgery in complex knee revisions with an acceptable mid-term outcome. Declarations Funding: No funds, grants, or other support was received for conducting this study. Competing interests: The authors have no relevant financial or non-financial interests to disclose. Ethics approval: This study was approved by the Institutional Review Board (IRB) under protocol number #6048. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments. Consent to participate: Not applicable (retrospective study with anonymized data). Clinical trial number: not applicable. Consent for publication: Not applicable. Availability of data, materials and/or code: The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request. Reporting guidelines: This study follows the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines for reporting observational cohort studies. The affiliations of the authors: Department of Orthopedics and Traumatology "Dr. Carlos E. Ottolenghi", Knee Division Hospital Italiano de Buenos Aires, Buenos Aires, Argentina Author Contribution Authors' contributions:All authors meet the ICMJE criteria for authorship.Ortiz, Ezequiel¹ [ORCID: 0000-0001-8292-8432]: Conception, study design, data collection, analysis, manuscript writing.Costantini, Julian¹ [ORCID: 0000-0001-8900-6254]: Interpretation of results, critical revision of manuscript.Costa Paz, Matias¹ [ORCID: 0000-0002-8217-1086 ]: Supervision, analysis support, critical review of manuscript.Carbo, Lisandro¹ [ORCID: 0000-0002-8053-0890]: Review of data, Supervision, manuscript editing, final approval.All authors approved the final version of the manuscript. References Huten D, Pasquier G, Lambotte JC. Techniques for filling tibiofemoral bone defects during revision total knee arthroplasty. Orthop Traumatol Surg Res. 2021;107(1S):102776. Lei PF, Hu RY, Hu YH. Bone Defects in Revision Total Knee Arthroplasty and Management. Orthop Surg. 2019;11(1):15–24. 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Clin Orthop Relat Res. 2015;473(1):185–9. Longo UG, De Salvatore S, Intermesoli G, Pirato F, Piergentili I, Becker R, et al. Metaphyseal cones and sleeves are similar in improving short- and mid-term outcomes in Total Knee Arthroplasty revisions. Knee Surg Sports Traumatol Arthrosc. 2023;31(3):861–82. Fakler JKM, Hepp P, Marquaß B, von Dercks N, Josten C. [Is distal femoral replacement an adequate therapeutic option after complex fractures of the distal femur?]. Z Orthop Unfall. 2013;151(2):173–9. Höll S, Schlomberg A, Gosheger G, Dieckmann R, Streitbuerger A, Schulz D, et al. Distal femur and proximal tibia replacement with megaprosthesis in revision knee arthroplasty: a limb-saving procedure. Knee Surg Sports Traumatol Arthrosc. 2012;20(12):2513–8. Vaishya R, Singh AP, Hasija R, Singh AP. Treatment of resistant nonunion of supracondylar fractures femur by megaprosthesis. Knee Surg Sports Traumatol Arthrosc. 2011;19(7):1137–40. Berend KR, Lombardi AV Jr. Distal femoral replacement in nontumor cases with severe bone loss and instability. Clin Orthop Relat Res. 2009;467(2):485–92. Utting MR, Newman JH. Customised hinged knee replacements as a salvage procedure for failed total knee arthroplasty. Knee. 2004;11(6):475–9. Springer BD, Sim FH, Hanssen AD, Lewallen DG. The modular segmental kinematic rotating hinge for nonneoplastic limb salvage. Clin Orthop Relat Res. 2004;(421):181–7. Haidukewych GJ, Springer BD, Jacofsky DJ, Berry DJ. Total knee arthroplasty for salvage of failed internal fixation or nonunion of the distal femur. J Arthroplasty. 2005;20(3):344–9. Mortazavi SMJ, Kurd MF, Bender B, Post Z, Parvizi J, Purtill JJ. Distal femoral arthroplasty for the treatment of periprosthetic fractures after total knee arthroplasty. J Arthroplasty. 2010;25(5):775–80. Smith TH, Gad BV, Klika AK, Styron JF, Joyce TA, Barsoum WK. Comparison of mechanical and nonmechanical failure rates associated with rotating hinged total knee arthroplasty in nontumor patients. J Arthroplasty. 2013;28(1):62–e71. Rosen AL, Strauss E. Primary total knee arthroplasty for complex distal femur fractures in elderly patients. Clin Orthop Relat Res. 2004;(425):101–5. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 11 Dec, 2025 Reviewers agreed at journal 18 Nov, 2025 Reviewers invited by journal 03 Nov, 2025 Editor invited by journal 04 Aug, 2025 Editor assigned by journal 01 Aug, 2025 Submission checks completed at journal 01 Aug, 2025 First submitted to journal 15 Jul, 2025 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. 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1","display":"","copyAsset":false,"role":"figure","size":182669,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 1\u003c/strong\u003e: flow chart patient selection.\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/4b5c4c69666abe9fa6931526.jpg"},{"id":95877228,"identity":"e7415e26-109b-4ba1-8707-66d6e18bfb88","added_by":"auto","created_at":"2025-11-14 01:41:36","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2056081,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 2:\u003c/strong\u003e Two stage Revision TKA with Massive Bone defect in femur and tibia. Metaphysical cones were used in femur and tibia to fulfill the defect.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/60f83db428342a6eaf67ea67.png"},{"id":96241210,"identity":"3debef27-5a56-4787-af26-6bade1495af5","added_by":"auto","created_at":"2025-11-19 07:10:23","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2255462,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 3a: \u003c/strong\u003ePJI treated in two steps. First step with a Knee megaspacer following a reconstruction in the second step with metaphyseal cones and mesh for the extensor mechanism.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/b91365297ca0ed8338b8e06b.png"},{"id":95877230,"identity":"426f6c3a-7705-444b-acf6-b8f0fbcc40a6","added_by":"auto","created_at":"2025-11-14 01:41:36","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1910839,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 3b: \u003c/strong\u003ePJI treated in two steps. Second step with metaphyseal cones and mesh for the extensor mechanism.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/da684abac205fa1323778ed7.png"},{"id":95877237,"identity":"f5871120-f635-446d-9516-5c37fb56372a","added_by":"auto","created_at":"2025-11-14 01:41:36","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":919843,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 4 : \u003c/strong\u003e6 year Follow up of Endomodel M, Aseptic Loosening in femoral component.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/c738fd32ae20c9b44015ff39.png"},{"id":96241414,"identity":"f6d6c96c-7597-4eb3-a1f4-1d9bbbd7263d","added_by":"auto","created_at":"2025-11-19 07:10:41","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":35786,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 5: \u003c/strong\u003ePre- and post-megaprosthesis placement KSS scores are detailed.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/5bb898fedf8689aa2b7cf306.jpg"},{"id":96241070,"identity":"98f8d130-34ee-4470-a415-4582df845a08","added_by":"auto","created_at":"2025-11-19 07:10:00","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":30798,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 6: \u003c/strong\u003eKaplan Meier,\u003cstrong\u003e \u003c/strong\u003eimplant survival.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/dfc0d1de7e1c5b3288fb67e5.jpg"},{"id":96363092,"identity":"abdda69f-35ca-4762-9ccd-90d08ddf4bb8","added_by":"auto","created_at":"2025-11-20 10:04:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":8100161,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7130371/v1/2099a672-c8ad-4aa3-8a29-a41ce3fec6a3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Mid-term Functional Outcomes and Complications rates in Knee Megaprosthesis for Non-Oncologic limb Salvage Surgeries: A Comprehensive Analysis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAlthough aseptic loosening remains one of the leading causes of revision total knee arthroplasty (24\u0026ndash;27%), revision procedures are often complicated by substantial bone loss resulting from diverse etiologies such as periprosthetic joint infection, osteolysis, component migration, periprosthetic fractures, and iatrogenic damage during implant removal [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Different techniques have been developed and refined for the treatment of these massive femoral and tibial bone defects such as cementation, augmentation modules, impacted bone grafts (autologous/heterologous), structural bone grafts, porous titanium or tantalum cones for isolated femur and tibia or in combination with cemented or uncemented stems, customized cones, and knee megaprosthesis [\u003cspan additionalcitationids=\"CR3 CR4 CR5 CR6\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOne of the main challenges during revision surgery is achieving secure implant fixation, especially in cases of severely compromised bone stock, which may extend to segmental deficiencies of up to 10 cm in length [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Generally, the management of bone defects is guided by the location, extent, and quality of the remaining bone. The gold standard for ensuring implant fixation involves achieving stability in at least two of the three areas, as described by the principles of Jones et al. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e\u003cp\u003eOver the past thirty years, in the pursuit of limb-salvage surgeries, megaprosthesis have played a prominent role due to the benefits in terms of restoring limb length, promoting early patient mobilization with early loading and rapid implant fixation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Indications for knee megaprosthesis have been expanded to non-oncologic prosthetic revisions with extensive bone loss, poor bone quality in distal femoral comminuted fracture in elder patients, pseudoarthrosis or malunions [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The modularity of these implants and the various degrees of constraint allow the surgeon to make modifications regarding the amount of bone stock to be resected and/or increase the degree of constraint in cases of ligament insufficiency during prosthetic revision [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. While the goal of megaprosthesis is to restore patient mobility and limb function, thereby improving the quality of life for these patients, they are not exempt from various complications that may jeopardize the goal of limb salvage [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Among the most frequent complications are PJI (5\u0026ndash;40%), aseptic loosening (4\u0026ndash;27%), soft tissue failure (11%), periprosthetic fractures (10%), and implant rupture (2\u0026ndash;4%), with proximal tibial rupture being the most common cause [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe study hypothesizes that the use of knee megaprosthesis in selected patients leads to favorable mid-term functional outcomes. The aim is to retrospectively evaluate the quality of life and clinical function in patients who underwent prosthetic revision with knee megaprosthesis due to massive non-oncologic bone defects.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eA single-center, observational, retrospective, and descriptive study was conducted. The corresponding protocol received approval from the institutional ethics committee, adhering to the principles of the Declaration of Helsinki (n: #6048). All patients provided signed informed consent for the respective investigation. Database was collected from electronic medical records, and patient follow-up was conducted through telephone and telemedicine.\u003c/p\u003e\u003cp\u003e\u003cem\u003eStudy Group\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eBetween 2008 and 2016, an average of 45 knee prosthetic revisions were performed annually by the Knee division at our institution. An average of 4 megaprosthesis per year (range 2\u0026ndash;6) were used. A total of 45 megaprosthesis were recorded, 5 were excluded due to lack of follow-up (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The following information was recorded: demographic data, initial diagnosis, date of surgery, implant used, stages of treatment, complications, failures rates, clinical outcomes and imaging status with x-ray.\u003c/p\u003e\u003cp\u003eInclusion criteria were patients with medial or lateral ligament insufficiency, bone defects affecting collateral ligament insertions, traumatic sequelae of the distal femur with ligament insufficiency, instability in revision arthroplasty, revision TKA (aseptic and septic causes), and a minimum follow-up of more than 2 years. Exclusion criteria were patients with oncologic resections involving the distal femur and proximal tibia for any cause.\u003c/p\u003e\u003cp\u003eFailure was defined as the need for either complete or partial \u0026iquest;revision for any reasons and poor to bad results with a fixed implant at the time of evaluation. Poor to bad results were defined as a summatory of a functional Knee Society Score (KSS) of less than 30, an Oxford Knee Score (OKS) of less than 19 points, and a Musculoskeletal Tumor Society Score (MSTS) of less than 9 points at time of evaluation. Failures were classified as mechanical and non-mechanical alterations. Mechanical failures included septic/ aseptic loosening, periprosthetic fractures, and/or implant ruptures. Non-mechanical failures (soft tissue defects) include extensor mechanism rupture, prolene mesh rupture, extensor mechanism revision, active fistulas, and soft tissue coverage deficits. Massive bone defects were classified according to the AORI system and measured intraoperatively in centimeters.\u003c/p\u003e\u003cp\u003e\u003cem\u003eSurgical Technique\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eAll procedures were performed by trained surgeons. Spinal or general anesthesia was administered based on anesthesia indications. All approaches were made through a medial parapatellar approach without a tourniquet and routine tranexamic acid was administered preoperatively. Extensible approaches, quadriceps snip, or TAT osteotomy were performed as needed. In cases with extensor mechanism injury, reconstruction was performed using allografts or reconstruction with polypropylene mesh. Single-stage implantation was indicated for patients with comminuted fractures of the distal femur, massive bone stock deficit in complex revisions and periprosthetic fractures. (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003ea, \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3\u003c/span\u003eb)\u003c/p\u003e\u003cp\u003e\u003cem\u003ePostoperative Rehabilitation\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eAll patients followed the same rehabilitation protocol, with partial weight-bearing at 24 hours postoperatively. During hospitalization, passive flexion-extension exercises were prescribed, with restricted range of motion (ROM) in patients who underwent extensor mechanism reconstruction and in patients who received a flap for soft tissue coverage. Scar healing and proper flap vascularization were monitored before authorizing knee mobility.\u003c/p\u003e\u003cp\u003e\u003cem\u003eClinical and Imaging Evaluation\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eRadiographic signs of loosening were classified by type and anatomical location (femoral, tibial, or combined) (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Serial imaging was conducted during follow-up using standardized anteroposterior and lateral knee radiographs, along with scanograms. Functional outcomes were assessed using the validated Spanish versions of the Oxford Knee Score (OKS), the Musculoskeletal Tumor Society Score (MSTS), the Knee Society Score (KSS), and the Visual Analog Scale (VAS) for pain. Clinical results were considered poor or very poor when the combination of a functional KSS\u0026thinsp;\u0026lt;\u0026thinsp;30, OKS\u0026thinsp;\u0026lt;\u0026thinsp;19, and MSTS\u0026thinsp;\u0026lt;\u0026thinsp;9 was present.\u003c/p\u003e\u003cp\u003eComplications were reported and classified using the Henderson classification, which includes: 1- Soft tissue failures (instability, tendon rupture, and wound dehiscence), 2- aseptic loosening (determined clinically and radiologically), 3- structural failures (periprosthetic fractures), and 4- infections (requiring component removal and spacer placement).\u003c/p\u003e\u003cp\u003eA Kaplan-Meier analysis was performed for implant survival, with an end point determined by any of the following events occurring first: death, amputation, revision with mega spacer or arthrodesis.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis:\u003c/h2\u003e\u003cp\u003eDescriptive analysis of variables was conducted, reporting continuous variables as mean and standard deviation or median interquartile range depending on distribution, and categorical variables as n (number of events) and their respective proportions. Continuous variables were compared using t-tests or Mann-Whitney tests depending on normal distribution, and categorical variables were compared using chi-square or Fisher's exact test as appropriate.\u003c/p\u003e\u003cp\u003eTo analyze whether Henderson scale values were associated with functional KSS, a linear regression model was conducted, with the functional KSS as the dependent variable and Henderson scale categories as the independent variable. Stata 14 software was used for analysis, and statistical significance was considered at P\u0026thinsp;=\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eForty patients out of forty-five fulfilled the inclusion and exclusion criteria and were included in the final analysis. Demographic data, baseline diagnosis, and surgical history are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographics. Abbreviations: Y: years, M: months, n: total number of patients. IQR: Interquartile Range. Avg: average.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eResults (N\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge \u0026ndash;years, median (IQR)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e72 (65\u0026ndash;77)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMen, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20 (50)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFollow Up (m) (RIQ)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e33 (28\u0026ndash;61)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeriod (y)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2008\u0026ndash;2020\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNumber of previous surgeries (avg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (1\u0026ndash;9)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUtilization n(%)\u003c/p\u003e\u003cp\u003e- Prosthetic revision post-infection\u003c/p\u003e\u003cp\u003e- Aseptic loosening\u003c/p\u003e\u003cp\u003e- Severe osteomyelitis\u003c/p\u003e\u003cp\u003e- Periprosthetic fractures\u003c/p\u003e\u003cp\u003e- Stem rupture\u003c/p\u003e\u003cp\u003e- Severe Valgus (Poliomielitis)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24 (57)\u003c/p\u003e\u003cp\u003e6 (15)\u003c/p\u003e\u003cp\u003e6 (15)\u003c/p\u003e\u003cp\u003e2 (5)\u003c/p\u003e\u003cp\u003e1 (2.5)\u003c/p\u003e\u003cp\u003e1 (2.5)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eImplant n (%)\u003c/p\u003e\u003cp\u003e- Endo-Model\u0026reg; M Link\u003c/p\u003e\u003cp\u003e- OSS\u0026trade; Orthopedic Salvage System Zimmer\u003c/p\u003e\u003cp\u003e- Endopr\u0026oacute;tesis MDT IOT Osteolife\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21 (54)\u003c/p\u003e\u003cp\u003e18 (43)\u003c/p\u003e\u003cp\u003e1 (3)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBone defect (cm)\u003c/p\u003e\u003cp\u003e- F\u0026eacute;mur\u003c/p\u003e\u003cp\u003e- Tibia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7.8 (1\u0026ndash;23)\u003c/p\u003e\u003cp\u003e3.1 (1\u0026ndash;13)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePredominant bone defect\u003c/p\u003e\u003cp\u003e- F\u0026eacute;mur\u003c/p\u003e\u003cp\u003e- Tibia\u003c/p\u003e\u003cp\u003e- F\u0026eacute;mur y tibia\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e29\u003c/p\u003e\u003cp\u003e10\u003c/p\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUtilization of tantalum cones n (%)\u003c/p\u003e\u003cp\u003e- F\u0026eacute;mur y tibia\u003c/p\u003e\u003cp\u003e- Tibia\u003c/p\u003e\u003cp\u003e- F\u0026eacute;mur\u003c/p\u003e\u003cp\u003eExtensor mechanism n (%)\u003c/p\u003e\u003cp\u003e- Reconstruction with Prolene Mesh\u003c/p\u003e\u003cp\u003e- Extensor Apparatus Graft\u003c/p\u003e\u003cp\u003e- Absorbs Traction\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11 (27)\u003c/p\u003e\u003cp\u003e6 (54)\u003c/p\u003e\u003cp\u003e4 (36)\u003c/p\u003e\u003cp\u003e1 (9)\u003c/p\u003e\u003cp\u003e9 (22)\u003c/p\u003e\u003cp\u003e4 (10)\u003c/p\u003e\u003cp\u003e4 (10)\u003c/p\u003e\u003cp\u003e1 (2.5)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe average number of previous surgeries before megaprosthesis implantation was 2.5 (range 1\u0026ndash;9), with 41% of the series having undergone 2 surgeries and 39% having undergone 3 surgeries. In most cases, the diagnoses at the time of revision were septic causes in 57% (24); diagnoses at the time of revision are in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eTwenty three out of forty (57%) presented with infections at time of consultation. The most frequently preoperative pathogen was positive cocci (CC+). After megaprosthesis implantation positive cultures were detected in 12 patients (30%). But the infection rate was 15% (6 patients), the most common germen recovered was gram-negative bacilli (BGN) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The standard treatment for these cases involved a two-stage procedure, including implant removal with sampling (bone and soft tissues), fixed knee mega spacer, and targeted antimicrobial therapy under infectious disease specialist supervision. Resolution of infected cases included arthrodesis in four patients, amputation in three patients, and spacer preservation in one patient at the time of the series evaluation.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eGerm rescues prior to megaprosthesis implantation and post-implantation. CC +: positive cocci; CC -: negative cocci; BG -: gram-negative bacilli; BG +: gram-positive bacilli.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGerms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePre- Op\u003c/p\u003e\u003cp\u003en= (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePost- Op\u003c/p\u003e\u003cp\u003en= (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCC +\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e22 (54)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBG -\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (24)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8 (40)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCC en racimo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (20)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMycosis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (20)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBG +\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCC -\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTOTAL\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e41\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e20\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cem\u003eClinical and Imaging Results\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eTwenty-six patients (63%) have a fixed implant, while 9 (21%) presented radiolucent images in the femur and tibia indicative of aseptic loosening (2 patients in the tibia and 7 in femur and tibia).\u003c/p\u003e\u003cp\u003eAn improvement was observed for the objective and satisfaction KSS (p\u0026thinsp;=\u0026thinsp;0.062 ; p\u0026thinsp;=\u0026thinsp;0.423, respectively). A decrease in the KSS for expectation and function was recorded (p\u0026thinsp;=\u0026thinsp;0.866 ; p\u0026thinsp;=\u0026thinsp;0.545, respectively) (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The Visual Analog Pain Scale (VAS) showed a 50% decrease in the initial score. In the postoperative evolution, the median Musculoskeletal Tumor Society Score (MSTS) was 16 points (IQR: 10\u0026ndash;25), and the Oxford Knee Score (OKS) was 24 (IQR: 14\u0026ndash;38) (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Poor to bad clinical results (defined by KSS function\u0026thinsp;\u0026lt;\u0026thinsp;30, OKS\u0026thinsp;\u0026lt;\u0026thinsp;19, and MSTS\u0026thinsp;\u0026lt;\u0026thinsp;9) were detected in 10% of patients (4 patients): two patients with soft tissue failure, one with aseptic loosening, and one with structural failure (periprosthetic fracture) (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Complications according to the Henderson classification were observed in 55% of cases (22 patients) (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical Outcomes.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eKSS Score\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePreoperative\u003c/p\u003e\u003cp\u003e(RIQ)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePostoperative\u003c/p\u003e\u003cp\u003e(RIQ)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eDelta KSS\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ep Value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eObjective\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e28 (27\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e11 (67\u0026ndash;78)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.062\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSatisfaction\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (10\u0026ndash;20)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e19 (20\u0026ndash;39)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.541\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eExpectation\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (9\u0026ndash;12)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9 (6\u0026ndash;15)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.866\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFunctional\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e35 (21\u0026ndash;56)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e36 (34\u0026ndash;70)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.545\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVAS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (8\u0026ndash;9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (0\u0026ndash;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.423\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOKS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e24 (14\u0026ndash;38)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMSTS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16 (10\u0026ndash;25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCutoff values to considering a poor outcome according to each score. The combination of all 3 scores was reported in 10% of the series.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePoor Clinical Outcomes\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003en\u0026thinsp;=\u0026thinsp;40 (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e- Postoperatoria functional KSS\u0026thinsp;\u0026lt;\u0026thinsp;30 pts\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8 (20)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e- OKS\u0026thinsp;\u0026lt;\u0026thinsp;19 pts\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14 (35)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e- MSTS\u0026thinsp;\u0026lt;\u0026thinsp;9 pts\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6 (15)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e- Postoperative KSS\u0026thinsp;\u0026lt;\u0026thinsp;30, OKS\u0026thinsp;\u0026lt;\u0026thinsp;19 and MSTS\u0026thinsp;\u0026lt;\u0026thinsp;9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4 (10)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComplications according to Henderson\u0026acute;s classification. A total of 55% complications were recorded.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"2\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHenderson\u0026acute;s Classification\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003en(%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1- Soft tissue Failure\u003c/p\u003e\u003cp\u003e(unstable TKA, tendon rupture and dehiscence)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e5 (22.7)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2- Aseptic Loosening\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e8 (36.4)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3- Structural Failure\u003c/p\u003e\u003cp\u003e(Periprosthetic Fracture)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2 (9.1)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4- Infections\u003c/p\u003e\u003cp\u003e(implant revision and spacer)\u003c/p\u003e\u003cp\u003e\u003cb\u003eTOTAL\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7 (31.8)\u003c/p\u003e\u003cp\u003e22 of 40 (55)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe improvement in the Minimal Clinically Important Difference (MCID) for Functional KSS is between 15 and 20 points or an improvement from 6.3 to 2 years of evolution for knee prosthetic revision surgeries according to different publications. In our series, we detected a 22% improvement (9 patients) with this clinical improvement in their evolution. For the MCID of the Objective KSS, a significant difference is an improvement of 6.6 points or a postoperative Objective KSS between 33 and 34. In our population, only 17% (7 patients) showed clinical improvement in their evolution.\u003c/p\u003e\u003cp\u003eA linear logistic regression was performed between Henderson complications and functional KSS. When comparing the KSS of groups without complications and with postoperative complications, the latter results were worse. The group with soft tissue failure complications recorded an average 4.8 points lower than the group without complications (p\u0026thinsp;=\u0026thinsp;0.748, CI: -35.999\u0026ndash;26.245). In contrast, the group with structural failures had a KSS average of 37 times lower than the group without complications, with statistically significant differences (p\u0026thinsp;=\u0026thinsp;0.046, CI: -74.273 - \u0026minus;\u0026thinsp;.81749). The results of KSS for complications related to aseptic loosening (p\u0026thinsp;=\u0026thinsp;0.360) and infections (p\u0026thinsp;=\u0026thinsp;0.299) were also lower but not statistically significant. Analyzing the relationship between postoperative functional KSS and radiologically loosening, we found that the group without loosening, the functional KSS had a mean of 54.3 (SD: 24.1) with a CI of 41.202\u0026ndash;67.545, and for the group with loosening, the functional KSS had a mean of 52 (SD: 22.6) with a CI of 36.751\u0026ndash;67.248. The functional KSS is similar in both patient groups, with no statistically significant difference between the means and their confidence intervals.\u003c/p\u003e\u003cp\u003e\u003cem\u003eImplant Survival\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eThe one-year survival was 80%, decreasing to 52% (95% CI: 35% \u0026minus;\u0026thinsp;67%) at 50 months and 21% (95% CI: 5.1% \u0026minus;\u0026thinsp;44%) at 100 months. Short-term survival of aseptic loosening was 100% with implant retention at the time of evaluation (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe primary outcome of this study reveals that the use of knee megaprosthesis in non-oncologic massive bone defects have a high postoperative complications rates (55%). While 22% of patients achieve the Minimal Clinically Important Difference (MCID), a significant improvement in objective KSS scores and postoperative satisfaction is observed. However, the KSS scores for expectation and function decreased, and 10% of patients experienced clinically poor to bad outcomes. These findings demonstrate favorable short-term implant survival but raise concerns about long-term longevity.\u003c/p\u003e\u003cp\u003e A systematic review published in 2020, involving 54 patients with an average age of 75 years and an average follow-up of 43 months, demonstrated that in over half of the series (55%), the primary indication was severe bone defects following failed primary arthroplasties, aligning with our casuistry, which was 62%. The most common postoperative complication was periprosthetic infection (18%), while in our series, it was 4.8%. Implant survival was 74.8% at one year postoperatively and 40.9% at ten years. In our experience, the one-year survival rate was similar to the reported 75% [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The septic loosening rate in our series was 15% (6 patients), while the aseptic loosening rate was 19% (8 patients), comparable to a systematic review on non-tumor knee prosthetic revisions [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Some patients exhibited prosthetic loosening images that did not translate into representative functional KSS values in the postoperative period.\u003c/p\u003e\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e details a summary of publications on reconstructions with non-oncological knee megaprostheses.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of clinical studies on megaprosthesis utilization for different causes.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAuthor\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003en\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ey\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eF-up\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eIndication (n=)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eComp rates (%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eHenderson \u003c/p\u003e\u003cp\u003eclassificaiton (n=)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eSurvivorship\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eVaishya R (2011) (30)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e74 (68\u0026ndash;85)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSupracondilar\u003c/p\u003e\u003cp\u003ePseudoartrosis\u003c/p\u003e\u003cp\u003e(10)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSoft Tissue Failure (2)\u003c/p\u003e\u003cp\u003eStructural Failure (1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eFakler JK\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2013) (28)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePeriprosthetic Fracture (6)\u003c/p\u003e\u003cp\u003eComplex Fracture (4)\u003c/p\u003e\u003cp\u003eMassive bone stock deficit (4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eStructural Failure (4)\u003c/p\u003e\u003cp\u003eInfections (2)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure (1)\u003c/p\u003e\u003cp\u003eAseptic Loosening (1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eVertesich\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2019) (12)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMassive bone stock deficit (30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (8)\u003c/p\u003e\u003cp\u003eAseptic Loosening (4)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure (3)\u003c/p\u003e\u003cp\u003eStructural Failure (1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e74.8% (1st year)\u003c/p\u003e\u003cp\u003e62.5% (3erd year)\u003c/p\u003e\u003cp\u003e41% (10 years)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eBerend \u0026amp; Lombardi\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2009) (31)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e39\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e76\u003c/p\u003e\u003cp\u003e(61\u0026ndash;87)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePeriprosthetic Fracture (13)\u003c/p\u003e\u003cp\u003eAseptic Loosening (11)\u003c/p\u003e\u003cp\u003eInfections (11)\u003c/p\u003e\u003cp\u003eFractures (2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (3)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure(1)\u003c/p\u003e\u003cp\u003eAseptic Loosening(1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e87%\u003c/p\u003e\u003cp\u003e(3erd year)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eUtting \u0026amp; Newman\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2004) (32)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e75\u003c/p\u003e\u003cp\u003e(61\u0026ndash;87)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePeriprosthetic Fracture (22)\u003c/p\u003e\u003cp\u003eAseptic Loosening (5)\u003c/p\u003e\u003cp\u003eInfections (3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (6)\u003c/p\u003e\u003cp\u003eStructural Failure (2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eSpringer\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2004) (33)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72\u003c/p\u003e\u003cp\u003e(47\u0026ndash;92)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePeriprosthetic Fracture (11)\u003c/p\u003e\u003cp\u003eAseptic Loosening (8)\u003c/p\u003e\u003cp\u003eFractures (5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (5)\u003c/p\u003e\u003cp\u003eStructural Failure (2)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure (1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eHaidukewych\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2005) (34)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66\u003c/p\u003e\u003cp\u003e(38\u0026ndash;86)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e60\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFractures (17)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eSoft Tissue Failure(3)\u003c/p\u003e\u003cp\u003eAseptic Loosening(2)\u003c/p\u003e\u003cp\u003eInfections (1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e91%\u003c/p\u003e\u003cp\u003e(5th year).\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eMortazavi\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2010) (35)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69\u003c/p\u003e\u003cp\u003e(54\u0026ndash;81)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePeriprosthetic Fracture (22)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eStructural Failure(4)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure(1)\u003c/p\u003e\u003cp\u003eAseptic Loosening(1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eSmith\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2013) (36)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFractures (29)\u003c/p\u003e\u003cp\u003eInfections (19)\u003c/p\u003e\u003cp\u003eAseptic Loosening (11)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e44\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (13)\u003c/p\u003e\u003cp\u003eAseptic Loosening(5)\u003c/p\u003e\u003cp\u003eStructural Failure(4)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure(1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eRosen \u0026amp; Strauss\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2004) (37)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e76\u003c/p\u003e\u003cp\u003e(68\u0026ndash;85)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFractures (24)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eStructural Failure(1)\u003c/p\u003e\u003cp\u003eInfections (1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eH\u0026ouml;ll\u003c/span\u003e\u003c/p\u003e\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e(2011) (29)\u003c/span\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e73\u003c/p\u003e\u003cp\u003e(53\u0026ndash;86)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFractures (14)\u003c/p\u003e\u003cp\u003eInfections (5)\u003c/p\u003e\u003cp\u003eAseptic Loosening (2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (6)\u003c/p\u003e\u003cp\u003eAseptic Loosening(2)\u003c/p\u003e\u003cp\u003eStructural Failure(2)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure(1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eOur Results\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(2025)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e40\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e72 (65\u0026ndash;77)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e33\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(28\u0026ndash;61)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003eInfections (24)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eMassive bone stock deficit (6)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eAseptic Loosening (6)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003ePeriprosthetic Fracture (2)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eStem rupture (1)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e\u003cb\u003e55\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cb\u003eAseptic Loosening (8)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eInfections (7)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eSoft Tissue Failure (5)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eStructural Failure (2)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u003cb\u003e52% (4th year)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(IC: 35% \u0026minus;\u0026thinsp;67%)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e21% (8th year)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(IC: 5% \u0026minus;\u0026thinsp;44%)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eTOTAL\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003e(Range)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e27 (10\u0026ndash;52)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72\u003c/p\u003e\u003cp\u003e(66\u0026ndash;76)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e37\u003c/p\u003e\u003cp\u003e(12\u0026ndash;60)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003eFractures (91)\u003c/p\u003e\u003cp\u003ePeriprosthetic Fracture (76)\u003c/p\u003e\u003cp\u003eInfections (51)\u003c/p\u003e\u003cp\u003eAseptic Loosening (43)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e\u003cp\u003e35\u003c/p\u003e\u003cp\u003e(8\u0026ndash;57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003eInfections (52)\u003c/p\u003e\u003cp\u003eAseptic Loosening (24)\u003c/p\u003e\u003cp\u003eStructural Failure (22)\u003c/p\u003e\u003cp\u003eSoft Tissue Failure (19)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe use of stems during prosthetic revisions has become an almost absolute indication, with ongoing debate about cementation concerning durability and long-term survival. The primary advantage of cemented stems is their ability to fill metaphyseal defects and allow antibiotic use, while uncemented stems preserve bone stock in potential revisions [\u003cspan additionalcitationids=\"CR24 CR25\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Regarding fixation quality in our series, 98% (39) of patients were cemented in both stems due to massive bone stock loss; only one patient received hybrid fixation with a non-cemented femoral stem and a tibial stem cemented with a metaphyseal cone. Although we couldn't detect significant differences between both techniques due to the low casuistry in using non-cemented stems, a systematic review and meta-analysis encompassing 70 articles concluded that survival rates are comparable regardless of the evaluation period. Aseptic loosening was the most common failure in prosthetic revisions in both constructs (cemented and cementless) over medium and long-term follow-up [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This result aligns with our casuistry, with aseptic loosening being the primary cause of failure in 20% (8 patients).\u003c/p\u003e\u003cp\u003eThe use of metaphyseal cones aims to fill bone defects and provide an additional fixation surface for the megaprosthesis, with the primary advantage of reducing the stem length if necessary [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. According to a systematic review and meta-analysis of 93 articles evaluating clinical and radiological outcomes of metaphyseal cones in prosthetic revision surgeries, the incidence of intraoperative fractures in patients treated with cones was 1.6% [95% CI: 0.7\u0026ndash;3.4], a postoperative fracture risk of 4.3% [95% CI: 2.7\u0026ndash;7], and postoperative infections at 8.5% [95% CI: 6\u0026ndash;12] [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. In our series, metaphyseal fixation cones were used in 26% (11 patients), primarily in AORI 3 defects; we recorded no intraoperative fractures during placement or postoperative periprosthetic fractures. Given the small sample size, we believe this reported complication was not expressed. Regarding prosthetic infections during metaphyseal cone placement, we recorded germ rescues in 45% (5 patients out of 11 in the series); two patients underwent implant extraction and spacer placement, while the rest were treated with antibiotics and implant retention. We observed no cone migrations or radiolucency images in the metaphyseal fixation zone at the time of evaluation.\u003c/p\u003e\u003cp\u003eConsidering Henderson's classification (which groups multiple complications, including soft tissue injuries), 55% of failures were recorded (23 patients). However, 20% (8 patients) subsequently underwent prosthetic revision by implant extraction. Definitive case resolution involved arthrodesis in four patients, amputation in three patients, and spacer retention in one patient at the time of evaluation. It is noteworthy that within the series, 10% of patients exhibited poor to bad outcomes despite a fixed implant at the time of evaluation. While the implant is functional, the quality of life falls short of expectations for the patient. From this, it can be inferred that 30% of the series falls into poor results and prosthetic revisions. The authors interpret this as a positive outcome considering the prior complications and bone stock deficit presented by these types of patients in the context of limb salvage surgery. Similar results were analyzed by other authors [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAs strengths of this research, we emphasize the exclusion of patients with coexisting neoplastic pathology and the exclusivity of the series regarding the use of megaprostheses. Although the series results are satisfactory, we believe they are largely attributed to being second-time revisions without prolonged oncological treatments that may, to a greater or lesser extent, deteriorate the patient.\u003c/p\u003e\u003cp\u003e\u003cem\u003eLimitations\u003c/em\u003e:\u003c/p\u003e\u003cp\u003eOur study was conducted as a single-center, retrospective, and descriptive investigation without a control group. The initial diagnoses at the time of megaprosthesis placement were diverse, such as in cases where megaprosthesis were used in two-stage revision surgeries or considered salvage procedures before opting for arthrodesis. This subset of patients, from the outset, had expectations and function markedly different from the group of patients in whom megaprosthesis indication was for severe valgus deformities, pure ligamentous instability, or massive bone defects. The heterogeneity in the patient population is another noteworthy aspect, as six patients in the series received a megaprosthesis due to secondary fungal infections following anterior cruciate ligament (ACL) reconstructions, thereby reducing the overall age mean.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eConsidering that 22% of the series surpassed the MCID, the rate of arthrodesis following knee megaprosthesis failure was 7.3%, with an aseptic loosening rate of 21%, a median survival of 60 months, and a 55% postoperative complication rate according to Henderson\u0026acute;s classification; only 20% of the series required an implant removal. These findings suggest that the utilization of knee megaprosthesis in revision surgeries with severe bone stock deficits is a viable option for limb salvage surgery in complex knee revisions with an acceptable mid-term outcome.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eNo funds, grants, or other support was received for conducting this study.\u003c/p\u003e\u003cp\u003eCompeting interests:\u003c/p\u003e\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u003c/p\u003e\u003cp\u003eEthics approval:\u003c/p\u003e\u003cp\u003eThis study was approved by the Institutional Review Board (IRB) under protocol number #6048. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments.\u003c/p\u003e\u003cp\u003eConsent to participate:\u003c/p\u003e\u003cp\u003eNot applicable (retrospective study with anonymized data).\u003c/p\u003e\u003cp\u003eClinical trial number: not applicable.\u003c/p\u003e\u003cp\u003e Consent for publication:\u003c/p\u003e\u003cp\u003eNot applicable.\u003c/p\u003e\u003cp\u003eAvailability of data, materials and/or code:\u003c/p\u003e\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\u003cp\u003e Reporting guidelines:\u003c/p\u003e\u003cp\u003e This study follows the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines for reporting observational cohort studies.\u003c/p\u003e\u003cp\u003eThe affiliations of the authors: Department of Orthopedics and Traumatology \"Dr. Carlos E. Ottolenghi\", Knee Division Hospital Italiano de Buenos Aires, Buenos Aires, Argentina\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAuthors' contributions:All authors meet the ICMJE criteria for authorship.Ortiz, Ezequiel\u0026sup1; [ORCID: 0000-0001-8292-8432]: Conception, study design, data collection, analysis, manuscript writing.Costantini, Julian\u0026sup1; [ORCID: 0000-0001-8900-6254]: Interpretation of results, critical revision of manuscript.Costa Paz, Matias\u0026sup1; [ORCID: 0000-0002-8217-1086 ]: Supervision, analysis support, critical review of manuscript.Carbo, Lisandro\u0026sup1; [ORCID: 0000-0002-8053-0890]: Review of data, Supervision, manuscript editing, final approval.All authors approved the final version of the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHuten D, Pasquier G, Lambotte JC. Techniques for filling tibiofemoral bone defects during revision total knee arthroplasty. Orthop Traumatol Surg Res. 2021;107(1S):102776.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLei PF, Hu RY, Hu YH. Bone Defects in Revision Total Knee Arthroplasty and Management. Orthop Surg. 2019;11(1):15\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVaishya R, Thapa SS, Vaish A. Non-neoplastic indications and outcomes of the proximal and distal femur megaprosthesis: a critical review. Knee Surg Relat Res. 2020;32(1):18.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQuevedo Gonz\u0026aacute;lez FJ, Meyers KN, Schraut N, Mehrotra KG, Lipman JD, Wright TM, et al. Do Metaphyseal Cones and Stems Provide Any Biomechanical Advantage for Moderate Contained Tibial Defects in Revision TKA? A Finite-Element Analysis Based on a Cadaver Model. 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The oxford knee score minimal clinically important difference for revision total knee arthroplasty. Knee. 2021;32:211\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKhow YZ, Liow MHL, Goh GS, Chen JY, Lo NN, Yeo SJ. Defining the minimal clinically important difference for the knee society score following revision total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2022;30(8):2744\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKorim MT, Esler CNA, Reddy VRM, Ashford RU. A systematic review of endoprosthetic replacement for non-tumour indications around the knee joint. Knee. 2013;20(6):367\u0026ndash;75.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWhiteside LA. Cementless fixation in revision total knee arthroplasty. Clin Orthop Relat Res. 2006;446:140\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMow CS, Wiedel JD. 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Knee Surg Sports Traumatol Arthrosc. 2011;19(7):1137\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBerend KR, Lombardi AV Jr. Distal femoral replacement in nontumor cases with severe bone loss and instability. Clin Orthop Relat Res. 2009;467(2):485\u0026ndash;92.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eUtting MR, Newman JH. Customised hinged knee replacements as a salvage procedure for failed total knee arthroplasty. Knee. 2004;11(6):475\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSpringer BD, Sim FH, Hanssen AD, Lewallen DG. The modular segmental kinematic rotating hinge for nonneoplastic limb salvage. Clin Orthop Relat Res. 2004;(421):181\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHaidukewych GJ, Springer BD, Jacofsky DJ, Berry DJ. Total knee arthroplasty for salvage of failed internal fixation or nonunion of the distal femur. J Arthroplasty. 2005;20(3):344\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMortazavi SMJ, Kurd MF, Bender B, Post Z, Parvizi J, Purtill JJ. Distal femoral arthroplasty for the treatment of periprosthetic fractures after total knee arthroplasty. J Arthroplasty. 2010;25(5):775\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSmith TH, Gad BV, Klika AK, Styron JF, Joyce TA, Barsoum WK. Comparison of mechanical and nonmechanical failure rates associated with rotating hinged total knee arthroplasty in nontumor patients. J Arthroplasty. 2013;28(1):62\u0026ndash;e71.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRosen AL, Strauss E. Primary total knee arthroplasty for complex distal femur fractures in elderly patients. Clin Orthop Relat Res. 2004;(425):101\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Knee Megaprosthesis, non oncologic reconstruction, Bone defects","lastPublishedDoi":"10.21203/rs.3.rs-7130371/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7130371/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eTo retrospectively evaluate the clinical and radiological outcomes of revision total knee arthroplasty using knee megaprosthesis in patients with severe bone loss from non-oncologic causes.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eBetween 2008\u0026ndash;2020 forty patients were evaluated with 33 month mean follow up (interquartile range: 28\u0026ndash;61) and 72-year median age (IQR: 65\u0026ndash;77). Radiographic analysis and a functional outcomes were carried out in the preoperative and at the final follow-up using Oxford Knee Score (OKS), Knee Society Score (KSS), Visual Analogue Pain Scale (VAS) and Musculoskeletal Tumor Society Score (MSTS). Complications were classified according to the Henderson classification system.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThree different implant systems were used: Endo-Model\u0026reg; M Link in 21 cases, OSS\u0026trade; Orthopedic Salvage System Zimmer Biomet in 18 cases, and the MDT prosthesis in one case. Indications were: 57% (24) prosthetic joint infection (PJI), 15% (6) aseptic loosening, 15% (6) severe osteomyelitis, 5% (2) fractures, 2.5% (1) femoral stem rupture and 2.5% (1) instability. The survival rate at 50 months was 52% (95% CI: 35% \u0026minus;\u0026thinsp;67%). Postoperative median MSTS score was 16 points (10\u0026ndash;25), KSS objective: 73 (67\u0026ndash;78), satisfaction: 30 (20\u0026ndash;39), expectation: 12 (6\u0026ndash;15), functional: 60 (34\u0026ndash;70), VAS: 3 (0\u0026ndash;8), and OKS: 24 (14\u0026ndash;38). Clinical improvement (MCID) was assessed in 22% (9) for functional KSS, and 17% (7) for objective KSS. Twelve out of forty (30%) had positive postoperative cultures and complication occurred in 55% of the series. According to Hendersons classification: 36.4% (8) were aseptic loosening, PJI 31.8 (7), soft tissue failure 22.7% (5) and structural failures 9.1% (2).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThe utilization of knee megaprosthesis in severe bone stock deficiency is a good option for limb salvage surgeries with an acceptable mid-term outcomes.\u003c/p\u003e\u003ch2\u003eLevel of evidence\u003c/h2\u003e\u003cp\u003eIV\u003c/p\u003e","manuscriptTitle":"Mid-term Functional Outcomes and Complications rates in Knee Megaprosthesis for Non-Oncologic limb Salvage Surgeries: A Comprehensive Analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-14 01:41:32","doi":"10.21203/rs.3.rs-7130371/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2025-12-11T11:38:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"25009340294886323884039093483577487136","date":"2025-11-18T09:53:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-03T08:49:49+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-08-04T08:47:22+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-01T10:03:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-01T10:02:14+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Musculoskeletal Disorders","date":"2025-07-15T11:52:51+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-musculoskeletal-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmsd","sideBox":"Learn more about [BMC Musculoskeletal Disorders](http://bmcmusculoskeletdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://author-welcome.nature.com/12891","title":"BMC Musculoskeletal Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c4dd7dbb-be1e-42b8-950b-e8de09e1e894","owner":[],"postedDate":"November 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-11-14T01:41:32+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-14 01:41:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7130371","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7130371","identity":"rs-7130371","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}