Comparative Efficacy of SMOT with Ilizarov Technique and SMOT with Internal Fixation in Varus Ankle Osteoarthritis

Comparative Efficacy of SMOT with Ilizarov Technique and SMOT with Internal Fixation in Varus Ankle Osteoarthritis | 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 Comparative Efficacy of SMOT with Ilizarov Technique and SMOT with Internal Fixation in Varus Ankle Osteoarthritis Cheng Wang, Xueqian Li, Shaoling Fu, Jiazheng Wang, Chenglin Wu, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4115368/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Varus ankle osteoarthritis is a degenerative condition characterized by varus deformity of the ankle joint, severely damaging patients’ quality of life. supramalleolar osteotomy (SMOT) has become one of the most commonly used joint-preserving surgeries for the treatment of varus ankle osteoarthritis. Both SMOT with Ilizarov technique and SMOT with internal fixation can be employed to correct varus deformity; however, there is limited literature comparing the efficacy of these two methods. Methods We retrospectively analyzed the clinical data of 52 patients (52 feet) who underwent SMOT for varus ankle osteoarthritis between August 2018 and June 2022. The patients were divided into two groups based on the surgical approach: the SMOT with Ilizarov technique group (treatment group, n = 19, 19 feet) and the SMOT with internal fixation group (control group, n = 33, 33 feet). Clinical evaluation parameters, including the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Ankle Osteoarthritis Score (AOS), Visual Analogue Scale (VAS), and ankle joint range of motion (ROM), were compared between the two groups. Radiographic parameters, including tibial articular surface angle (TAS), tibial lateral surface angle (TLS), talar tilt (TT), tibiocrural angle (TC), tibial medial malleolar angle (TMM), hindfoot alignment angle (HAA), and modified Takakura stage, were also compared. Furthermore, complications such as infection, delayed healing, and nonunion were recorded and compared between the two groups. Results Preliminary results showed that both SMOT with Ilizarov technique and SMOT with internal fixation significantly improved clinical scores and radiographic parameters. All 52 patients (52 feet) were followed up for an average of 39.19 ± 10.82 weeks. In the postoperative period, 50 patients achieved grade I wound healing, while 2 patients in the control group experienced wound infection. Both groups showed statistically significant improvements in AOFAS ankle-hindfoot score, AOS, VAS, and ROM at the last follow-up (P < 0.001). TAS, TT, TC, TMM, HAA, and modified Takakura stage also significantly improved compared to preoperative measurements (P < 0.001). At the last follow-up, no statistically significant differences were observed between the two groups in terms of AOFAS ankle-hindfoot score, AOS functional score, VAS, TAS, TLS, TT, TC, TMM, or modified Takakura stage. However, the treatment group demonstrated significantly greater improvements in AOS pain score (P = 0.011), ROM (P = 0.024), and HAA (P = 0.031) compared to the control group. Correlations were observed between the changes in TT, TC, and the last follow-up AOFAS ankle-hindfoot score, VAS, and AOS pain score in the radiographic results. Conclusion This study suggests preliminarily that SMOT with Ilizarov technique is a more effective treatment option for varus ankle osteoarthritis compared to SMOT with internal fixation. For moderate to severe cases of varus ankle osteoarthritis, SMOT with Ilizarov technique provides satisfactory outcomes by correcting both bone and soft tissue deformities, achieving better restoration of ROM, superior correction of hindfoot alignment, and minimizing postoperative complications compared to SMOT with internal fixation. Additionally, it minimizes postoperative complications. Improvements in TT and TC during SMOT may lead to better clinical outcomes. Trial registration: The registration number was ChiCTR1900020579, and date of registration was 2019-01-09. SMOT Ilizarov external fixation ankle osteoarthritis varus surgery Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Background Ankle osteoarthritis (OA) is a degenerative condition characterized by bone spur formation, subchondral sclerosis, joint space narrowing, and varus/valgus deformity of the ankle joint, severely affecting patients’ walking function and even leading to disability, affecting 1% of the global population [1,2] . Ankle osteoarthritis can be classified into primary/idiopathic, secondary, and post-traumatic types, with post-traumatic ankle osteoarthritis being the most common, with 55% of patients presenting with varus deformity and only 8% with valgus deformity [2-4] . In the 1970s and 1980s, some scholars first reported the application of supramalleolar osteotomy (SMOT) in the treatment of diseases with varus or valgus deformities of the ankle joint, such as nonunion after fractures, poliomyelitis, rheumatoid osteoarthritis, and hemophilic arthropathy [5-10] . This surgical technique can effectively correct deformities, restore joint alignment, preserve joint function, improve articular cartilage conditions, protect the epiphyseal plates in adolescents, delay the progression of OA, and postpone or avoid ultimate surgeries. It is suitable for patients aged 15° associated with ankle osteoarthritis, ankle fusion contraindication, subtalus deformities, and previous treatment or alternative options before ultimate surgery [11-25] . The Ilizarov technique can achieve deformity correction through bone and soft tissue traction methods and is suitable for patients with reduced bone quality, poor soft tissue conditions, poor coverage, leg length discrepancy, and unstable complex deformity osteotomy sites [26-36] . In 2003, Sen C et al. [37] reported the technique of percutaneous drilling osteotomy with Ilizarov Technique for SMOT, which effectively corrected foot and ankle deformities after 3-10 weeks of correction and distraction periods. In recent years, the method of SMOT combined with medial distraction arthroplasty has been introduced; however, there are no reports on the combination of SMOT with the Ilizarov technique. The purposes of this study were to (1) compare the clinical and radiographic outcomes between SMOT with Ilizarov technique and SMOT with internal fixation, and (2) assess the relationship between radiographic parameters and clinical outcomes after SMOT. Methods Study design and setting Inclusion criteria: (1) Takakura stage II-IIIb varus ankle osteoarthritis; (2) worsening pain and seriously impaired daily activities after 6 months of conservative treatment; (3) intact lateral tibial articular surface and 2 year after surgery. Exclusion criteria: (1) Takakura stage IV ankle osteoarthritis with severe joint degeneration; (2) tibial double osteotomy procedure using internal fixation; (3) extensive bone and soft tissue defects after previous surgeries; (4) complications such as Charcot joint, rheumatoid osteoarthritis, ankle deformity, chronic infection, and comorbidities of diabetes, smoking, osteoporosis, and other vascular and neurological diseases. Participants From August 2018 to June 2022, a total of 55 patients with varus ankle osteoarthritis were identified for this study, with 52 patients followed up after surgery and 3 lost follow-up. Among 52 patients, 19 patients in the SMOT with Ilizarov technique group (treatment group) and 33 patients in the SMOT with internal fixation group (control group) were included in this study. All patients underwent weight-bearing anteroposterior ankle X-rays, weight-bearing lateral ankle X-rays, Saltzman X-rays, ankle joint computer tomography (CT) scans, and measurements of tibial articular surface angle (TAS), tibial lateral surface angle (TLS), talar tilt (TT), tibiocrural angle (TC), tibial medial malleolar angle (TMM), hindfoot alignment angle (HAA), and modified Takakura stage by two experienced attending physicians (Figures 1, 2). Treatment group: The treatment group consisted of 19 patients (19 feet), including 11 males and 8 females, with an average age of 44.21±14.27 years, a body mass index (BMI) of 25.94±4.41 kg/m2, a disease duration of 7.42±6.34 years, and a follow-up time of 37.63±10.57 months. According to the modified Takakura stage, there were 5 cases of stage II, 7 cases of stage IIIa, and 7 cases of stage IIIb. Control Group: The control group consisted of 33 patients (33 feet), including 18 males and 15 females, with an average age of 50.45±14.06 years, a BMI of 25.18±2.71 kg/m2, a disease duration of 8.38±6.36 years, and a follow-up time of 40.09±11.02 months. According to the modified Takakura stage, there were 12 cases of stage II, 15 cases of stage IIIa, and 6 cases of stage IIIb. There were no statistically significant differences in general data between the two groups (P > 0.05) (Table 1). Preoperative Planning Weight-bearing examination is necessary, and weight-bearing anteroposterior ankle X-rays, and weight-bearing lateral ankle X-rays play a key role in comparing the affected and unaffected ankles, assessing leg length discrepancy, pelvic tilt, hindfoot varus/valgus deformity, and knee varus/valgus deformity [38] . Ankle joint CT scan has a good evaluation effect on ankle osteoarthritis that are difficult to determine by X-ray, and can accurately define the specific affected area of the ankle joint. In order to achieve complete adjustment of the foot and ankle deformities, this study performed medial wedge osteotomy at the CORA level [39] . Varus ankle osteoarthritis often involve the coronal and/or sagittal planes, affecting multiple joints above and below the ankle, and affecting the overall lower limb alignment. Therefore, comprehensive identification and precise planning must be performed preoperatively [40] . Preoperative planning at a level higher or lower than the deformity level will result in translation displacement. This study performed ankle joint thin-layer CT scanning with a slice thickness and interval of 0.625 mm. Arigin 3D pro (Shanghai Xinjian Medical Technology Co., Ltd.) was used to create a three-dimension (3D) reconstruction model to determine the center of rotation and angulation (CORA). Finite element mechanical analysis was used to create a digital model of varus ankle osteoarthritis, and parameters such as correction angle, osteotomy position, and size of wedge bone graft required for deformity correction were calculated based on the model. The target TAS was set at 90-92°, the target TLS was set at 80-85°, and the target TT was set at 0-4°. Surgical procedure The patients were placed in a supine position under general anesthesia with the ipsilateral hip elevated and a tourniquet applied after routine disinfection. An incision was made in the anterior aspect of the ankle, which served as the observation and operation ports for arthroscopy. Arthroscopy was performed to explore and clean the synovial and fibrous scar tissue, bone spurs, and joint spaces. Complete release of the ankle joint was performed until dorsiflexion reached 20°. SMOT was then performed. A longitudinal incision was made above the medial malleolus, exposing the osteotomy plane. A pre-designed 3D printed guide for SMOT was installed through the medial incision, and Kirschner wires were used to fix the guide. Osteotomy was performed at the designated site using an oscillating saw with guidance from the osteotomy guide. Care was taken to preserve the outer cortex of the tibia on the lateral side as a pivot point. Fluoroscopy was used to confirm the satisfactory position and correction of the osteotomy, and the guide was removed. Then a pre-designed distractor was gently applied to the medial osteotomy surface. The treatment group used Ilizarov ring fixator for external fixation. Kirschner wires and Schanz pins were inserted into the distal tibia, calcaneus, wedge bone of the midfoot, and metatarsals 1-5. A ring frame was installed in the middle and lower segments of the tibia and a semi-ring frame was installed in the foot. These frames were assembled using connecting rods. Traction was applied to the ankle joint, and the foot and ankle were maintained in a dorsiflexion-neutral position to allow postoperative joint movement. Intraoperative fluoroscopy was used to confirm that the ankle joint space had been stretched to 5mm (Figure 3, 4). In the control group, autogenous bone graft from the ipsilateral ilium or allograft cortical bone graft was used. These grafts were shaped according to a pre-designed trial model and implanted into the osteotomy site to fill the gap. An appropriate locking plate was selected to fix the distal tibia osteotomy site (Figure 5). Preoperatively, the need for fibular osteotomy was determined based on fibular length and joint congruity. If necessary, fibular osteotomy was performed above the distal tibiofibular syndesmosis to adjust the position and length of the fibula. For patients with residual hindfoot varus deformity, calcaneal osteotomy was performed. For those with chronic ankle instability, a modified Brostrom procedure was performed intraoperatively. For patients with osteochondral lesions of the talus, the lesions was debrided using microfracture/bone marrow stimulation during arthroscopy. For patients with reduction of medial clear space, triangular ligament release was performed. For patients with limited dorsiflexion range of motion, per Silverskiod test results, either gastrocnemius recession or Achilles tendon lengthening was performed. Fluoroscopy was used to confirm restoration of the tibiofibular joint space and correction of the hindfoot alignment. Auxiliary procedures in this study included a modified Brostrom procedure in 38 cases, gastrocnemius recession or Achilles tendon lengthening in 32 cases, iliac bone grafting in 32 cases, arthroscopic microfracture in 19 cases, calcaneal osteotomy in 16 cases, posterior ankle arthroscopy in 2 cases, and LARS ligament reconstruction in 1 case. Aftercare and follow-up routine In the treatment group, patients were instructed to perform joint distraction with the Ilizarov ring fixator twice a day, with a distraction rate of 0.5mm each time, for at least 3 months. Weight-bearing and ankle joint motion were prohibited for the first 6 weeks after surgery. The Ilizarov ring fixator was removed 3-4 months postoperatively, and ankle joint manipulation was performed under anesthesia to prevent joint adhesion. After the removal of the Ilizarov ring fixator, a inflatable walking boot was immediately used to allow partial weight-bearing for 1 month. After confirming the bony union of the osteotomy site through imaging examination, full weight-bearing could start. Following the removal of internal fixation, physiotherapy was continued for 2 months to improve range of motion, lower limb strength, and proprioception (Figure 6). In the control group, conventional support fixation was applied using an inflatable walking boot or short leg cast after surgery. Leg elevation training, active toe and ankle joint exercises could be performed from the second day onwards. Weight-bearing was prohibited within the first 6 weeks, and after confirming the formation of callus at 6 weeks postoperatively, the patients were allowed to bear weight with the support. After confirming the bony union of the osteotomy site through imaging examination, full weight-bearing could start (Figure 7). Outcome measures Outcome measurements included the AOFAS ankle-hindfoot score, AOS, VAS, ROM, as well as radiographic parameters including TAS, TLS, TT, TC, TMM, HAA, and modified Takakura grade. The AOFAS ankle-hindfoot score assesses pain, function, gait, range of motion, stability, and alignment, with a maximum score of 100. Scores of 90-100 are considered excellent, 75-89 good, 50-74 fair, and below 50 poor. VAS score ranges from 0 to 10, indicating the severity of pain. To analyze changes in imaging grading, a quantitative scoring system was used, with scores of 2, 3, 4, and 5 assigned to modified Takakura grades II, IIIa, IIIb, and IV, respectively. Complications were also observed. Statistical Analysis Statistical analysis was performed using SPSS 26.0 software. The Shapiro-Wilk test was used to assess the normality of the data. Normally distributed continuous variables are presented as mean ± standard deviation (x̄ ± s), and paired-sample t -tests were used to compare preoperative and final follow-up measurements within each group. Independent-sample t -tests were used to compare measurements between the two groups. Skewed distributed continuous variables are presented as M (Q1, Q3), and Wilcoxon signed-rank tests were used to compare preoperative and final follow-up measurements within each group. Wilcoxon rank-sum tests were used to compare measurements between the two groups. Spearman’s correlation analysis was used to assess the correlation between radiographic parameters (TAS, TT, TLS, TT, TC, TMM, HAA, modified Takakura stage) and clinical outcomes (VAS and AOFAS scores) at the final follow-up. A p-value < 0.05 was considered statistically significant. Results General information comparison All 52 patients were followed up after surgery, with a mean follow-up time of 37.63±10.57 months in the treatment group and 40.09±11.02 months in the control group. In the control group, wound healing was classified as Grade I in 50 patients, while 2 patients developed wound infections at 2 and 3 months postoperatively, respectively. The infections were successfully treated with debridement, vacuum-sealing drainage (VSD), local dressing changes, and intravenous antibiotics. In the treatment group, all wounds healed as Grade I, and the Ilizarov ring fixator was removed at an average of 13.86±1.68 weeks with no cases of wound infection or need for additional surgeries. Neither group experienced complications such as ankle osteoarthritis progression, deformity recurrence, or nonunion. Clinical efficacy comparison Compared to preoperative values, both groups showed statistically significant improvements (P < 0.001) in AOFAS ankle-hindfoot score, AOS, VAS, and ROM at the final follow-up. Except for TLS, both groups exhibited statistically significant improvements (P 0.05) between the two groups in AOFAS score and AOS function score at both preoperative and final follow-up. However, the treatment group showed significantly better improvement in AOS pain score (P = 0.011) and ROM (P = 0.024) compared to the control group, with statistical significance. Regarding radiographic parameters, there were no statistically significant differences (P > 0.05) between the two groups in TAS, TLS, TT, TC, TMM, and modified Takakura grade. However, the improvement in HAA (P = 0.031) was significantly better in the treatment group compared to the control group (Table 3). According to the modified Takakura stage, in the treatment group, all 5 cases of Grade II improved to Grade I, 5 cases of Grade IIIa improved to Grade I, 2 cases improved to Grade II, and all 7 cases of Grade IIIb improved to Grade II. In the control group, 2 cases of Grade II improved to Grade 0, 10 cases of Grade IIIa improved to Grade I, 9 cases improved to Grade I, 6 cases improved to Grade II, 5 cases of Grade IIIb improved to Grade II, and 1 case improved to Grade IIIa (Table 4, 5). Spearman correlation analysis showed that at the final follow-up, there were statistically significant correlations (P < 0.05) between the changes in TT and TC and the final AOFAS ankle-hindfoot score, VAS, and AOS pain score. ΔTT was positively correlated with the AOFAS ankle-hindfoot score (r=0.336) and negatively correlated with the VAS (r=-0.297) and AOS pain score (r=-0.358). ΔTC was positively correlated with the AOFAS ankle-hindfoot score (r=0.299) and negatively correlated with the VAS (r=-0.278) and AOS pain score (r=-0.348) (Figure 8, Table 6). Complications In the control group, 2 cases of wound infection occurred at 2 and 3 months postoperatively, respectively. These infections were managed with soft tissue debridement, VSD, short-term local dressing changes, and intravenous antibiotics, resulting in Grade II wound healing. In the treatment group, all wounds healed as Grade I, and there were no cases of wound infection or need for additional surgeries. Early removal of fixation, pin tract infections, and soft tissue irritation were not observed in either group. Neither group experienced complications such as ankle osteoarthritis progression, deformity recurrence, nonunion, delayed healing, or tendon vascular nerve injury. Discussion Background and rationale In the surgical treatment of varus ankle osteoarthritis, arthroscopic debridement, medial distraction arthroplasty, and SMOT have gained wide attention for their advantages in pain relief and increased ROM without sacrificing the ankle joint. In recent years, numerous clinical studies on SMOT have consistently demonstrated its effective deformity correction, satisfactory outcomes, and good clinical efficacy, making it an increasingly preferred option for joint-preserving surgery in patients with varus ankle osteoarthritis [11-25] . SMOT techniques include closed wedge, open wedge, dome osteotomy, tractional, rotational, and stepped osteotomy, often combined with other surgical approaches. Open wedge SMOT offers advantages such as restoration of leg length, correction of varus angulation, inherent stability, and the ability to correct minor lateral deformities due to its translational properties. Moreover, it exhibits faster bone healing compared to closed wedge osteotomy [16,18,41-45] . However, open wedge osteotomy carries risks of delayed union, nonunion, and graft rejection, as well as increased tension on the posterior tibial neurovascular bundle, making it less suitable for patients with diabetes, rheumatoid osteoarthritis, smoking, or vascular diseases [35] . The fixation method during SMOT should consider the surgeon’s experience, patients’ skin condition, ankle joint translational and rotational deformities, and available bone stock [16] . Clinical Outcomes of SMOT with Ilizarov Technique External fixation is necessary for patients with complex deformities of ankle osteoarthritis who are not suitable for one-stage correction and require gradual correction [45,46] . Compared to internal fixation methods, external fixation has the greatest advantage in gradually correcting complex multiplanar deformities, which is beneficial for precise correction of severe residual deformities and leg length discrepancies, as well as improving joint stiffness through distraction, vegetating and stimulating chondrocytes [34,47-50] . Large-scale studies and long-term results have shown that patients with severe post-traumatic ankle osteoarthritis benefit from joint distraction in terms of symptom relief and improved function [3,51,52] . In 1995, Van Valburg et al. [46] first used Ilizarov ring fixators for gradual distraction before arthrodesis or arthroplasty. The Ilizarov ring fixator can be configured according to the deformity requirements, but it has a steep learning curve [53,54] . Subsequent studies by Eidelman et al. [55] described the use of the Taylor spatial frame for distal tibial deformity correction, which facilitated the surgical procedure of distal tibial osteotomy. Elomrani et al. [56] demonstrated that 41 out of 55 patients with distal tibial deformities achieved good or excellent surgical outcomes. Horn et al. [47] reported that in patients treated with SMOT, correction of tibial deformities using a six-axis circular external fixator was especially effective for complex oblique deformities, soft tissue injuries, and patients with previous surgeries or infections. Zhao et al [57,58] initially applied the combination of SMOT and medial distraction arthroplasty in a case of Takakura Grade IIIb varus ankle osteoarthritis with a TT angle of 21.3°, and subsequently conducted a retrospective controlled study demonstrating the effectiveness of this combination for large TT angles in varus ankle osteoarthritis. In this study, SMOT with Ilizarov technique in the treatment group showed significant advantages in correcting bony and soft tissue deformities, leading to better restoration of joint mobility and more satisfactory clinical outcomes. Although the treatment group had a longer operative time, the average duration was still within an acceptable range, considering the potential impact of the learning curve. Additionally, there were no statistically significant differences between the two groups in terms of fluoroscopy time and blood loss. Radiographic Outcomes of SMOT with Ilizarov Technique Previous studies have shown that SMOT can improve TAS, TC, and TMM [18,23,59-62] . Some scholars have suggested correcting TAS within the normal range [17,63-65] , while others have recommended a slight overcorrection or the use of calcaneal osteotomy to correct residual deformities [18,41,59,66-70] . However, the optimal correction angle for SMOT remains unclear [71] . Traditional SMOT based on TAS has led to significant changes in the mechanical axis of the ankle joint, indicating that TAS is not a reliable indicator for determining the correction angle of SMOT [72] . We propose correcting TAS to approximately 95°, which corresponds to a 5° external rotation of the ankle joint. Excessive external rotation does not necessarily improve the correction of TT. Tanaka et al. [59,66] suggest that SMOT cannot achieve Grade I in cases with a TT angle greater than 10° or Takakura Grade IIIb deformity, resulting in less satisfactory clinical outcomes. Lee et al. [73,74] found that SMOT is not suitable for severe ankle osteoarthritis with significant TT and joint space narrowing, and they identified a preoperative TT angle greater than 7.3° as the optimal predictive indicator for high postoperative TT angles. Tanaka et al. [59,66] compared clinical outcomes with radiographic grading based on the modified Takakura stage and concluded that clinical outcomes did not improve in cases of Grade IIIb ankle osteoarthritis. Kim et al. [75] included only Grade II and IIIb patients in their study and found that postoperative radiographic results did not significantly influence clinical outcomes. However, Hongmou et al. [60] and Lai et al. [23] reported good functional outcomes even in cases with high TT and Takakura Grade IIIb deformity. In our study, there were no statistically significant differences between preoperative and postoperative TLS, possibly due to the presence of anterior osteophytes in varus ankle osteoarthritis, which may interfere with TLS measurements. Both groups showed statistically significant improvements in TAS, TT, TC, TMM, and modified Takakura grade at the final follow-up compared to preoperative values. There were no statistically significant differences between the two groups in TAS, TLS, TT, TC, TMM, and modified Takakura grade at the final follow-up, but the treatment group showed a statistically significant advantage in terms of HAA improvement compared to the control group. These results may demonstrate the corrective ability of SMOT with Ilizarov technique in realigning the hindfoot alignment and rearranging the foot and ankle through joint distraction and soft tissue manipulation. Additionally, the modified Takakura grade at the final follow-up showed that the control group achieved a reduction in modified Takakura grade below Grade I in 52.63% of patients, while the treatment group achieved a reduction below Grade I in 63.64% of patients, suggesting the advantage of SMOT with Ilizarov technique in modifying the stage of varus ankle osteoarthritis and delaying joint degeneration. Although not statistically significant, the TT improvement in the treatment group was somewhat better than that in the control group. Furthermore, 89.47% (17/19) of patients in the treatment group achieved a return to normal TT levels, compared to only 78.79% (26/33) in the control group. However, this needs to be further validated through larger sample size and longer-term follow-up. The Relationship between Radiographic Parameters and Clinical Outcomes after SMOT Additionally, this study verified through Spearman correlation analysis that there is a statistically significant correlation between ΔTT, ΔTC, and AOFAS ankle-hindfoot scores, VAS, and AOS pain scores at the final follow-up. The absolute values of the correlation coefficients were all within the range of 0.2 to 0.4, indicating a weak positive correlation between ΔTT, ΔTC, and AOFAS ankle-hindfoot scores, as well as a weak negative correlation between ΔTT, ΔTC, and VAS scores and AOS pain scores. This suggests that improvements in TT and TC during SMOT may lead to better clinical outcomes. Surgical Technique and Points Currently, the talar tilt and abnormal internal rotation caused by varus ankle osteoarthritis have gained increasing attention. Scholars generally believe that ankle osteoarthritis is not only a bone deformity that leads to joint malalignment but also a soft tissue imbalance [24,57,58,76,77] . After three months of opening the medial side of the ankle joint, the internal and external soft tissue balance will be partially restored, and the TT angle will be further corrected [57] . In our study, correction started on the first day after surgery, with a correction rate of 1 mm/day. The average external fixation time was 13.86±1.68 weeks, and modular adjustments were made to achieve multi-level, multi-plane, and multi-stage corrections based on individual patient needs and specific conditions. To the best of our knowledge, this is the first retrospective case-control study comparing the outcomes of SMOT with Ilizarov technique and SMOT with internal fixation. Our study believes that correcting the soft tissue imbalance is crucial for complete correction of ankle joint deformities when faced with excessive TT angles in varus ankle osteoarthritis. The Ilizarov circular external fixator cannot correct the bony deformity but can maintain hindfoot alignment, release the lateral structures, and achieve complete correction in patients with varus ankle osteoarthritis when combined with SMOT. After SMOT and internal fixation, there may still be postoperative hindfoot rotation deformities, and excessive stress on the medial side of the ankle joint during weight-bearing. Progressive correction using Ilizarov technique can also minimize the risk of vascular and nerve injuries. When planning for SMOT, all accompanying issues related to medial and lateral soft tissues and periarticular deformities should be thoroughly addressed in the preoperative planning. In conclusion, Ilizarov technique is beneficial for restoring ankle joint mobility, and SMOT is effective in correcting internal rotation deformities of the ankle joint. Both SMOT and Ilizarov technique require high technical skills from surgeons, necessitating extensive and meticulous preoperative planning and a longer learning curve. According to the current literature, the incidence of progressive degenerative changes in the ankle joint after SMOT for ankle osteoarthritis is as high as 25%, and the incidence of infections and wound healing issues is as high as 22% [19] . In the control group of this study, there were 2 cases of postoperative wound infections, which were treated with debridement and negative pressure wound therapy (VSD). Short-term local dressing changes and intravenous antibiotics were used for infection prevention, and all wounds healed at stage II. Adhesions, synovitis, and soft tissue impingement can cause persistent pain after SMOT [78] . Comprehensive exploration and cleaning were performed using arthroscopy in this study, potentially avoiding most cases of postoperative persistent pain. Limitations The limitations of this study include: (1) the retrospective study design may lead to bias in data accuracy, so two experienced attending physicians were specifically responsible for measuring the parameters; (2) the follow-up time was short, and the sample size was small, resulting in type II statistical errors. Long-term follow-up is needed to further assess the mid- to long-term efficacy, but early results have preliminarily confirmed the favorable effects of SMOT with Ilizarov technique in relieving pain, correcting deformities, and improving function; (3) this study simultaneously combined several auxiliary surgeries, resulting in a certain degree of heterogeneity, which may lead to confounding effects in the evaluation of patients’ function and efficacy; (4) due to the subjective difficulties of Second Look patients, it was not possible to observe the internal condition of the joint, thus further research is needed for validation. Conclusion In conclusion, this study preliminarily demonstrates that SMOT with Ilizarov technique is a more effective treatment option for varus ankle osteoarthritis compared to SMOT with internal fixation. For moderate to severe varus ankle osteoarthritis, SMOT with Ilizarov technique has satisfactory efficacy in relieving pain, correcting deformities, and improving function. It not only corrects both bony and soft tissue deformities but also improves joint mobility better than SMOT with internal fixation, while minimizing postoperative complications. During SMOT, improvements in TT and TC may lead to better clinical outcomes. Further prospective studies with larger sample sizes are needed to validate and expand these findings. Abbreviations SMOT, supramalleolar osteotomy AOFAS, American Orthopaedic Foot and Ankle Society AOS, ankle osteoarthritis score VAS, visual analogue scale ROM, range of motion TAS, tibial articular surface angle TLS, tibial lateral surface angle TT, talar tilt TC, tibiocrural angle TMM, tibial medial malleolar angle HAA, hindfoot alignment angle OA, ankle osteoarthritis BMI, body mass index CT, computer tomography 3D, three-dimension VSD, vacuum-sealing drainage Declarations Ethics Approval and Consent to Participate This study was approved by Ethics Committee of Shanghai Sixth People's Hospital，conducted in accordance with the ethical standards in the 1964 Declaration of Helsinki, approved by the institutional ethics review board, and obtained written informed consent from all participants. The ethics approval number was 2020-135, and the clinical trail registration number was ChiCTR1900020579. Consent to Publish Not Applicable. Data Availability Statement All data generated or analyzed during this study are included in this published article. Competing Interests All authors declare no conflicts of interest. Funding This research was funded by Bio-medical Engineering Program of Shanghai Jiao Tong University Star Plan (YG2022ZD018); Key Research and Development Program of National Ministry of Science and Technology (2022YFC2009500). Authors' Contributions CWa, XL and SF were responsible for conceiving and designing the experiments, statistical analysis, and drafting the manuscript. JW and CWu were involved in collecting patient data and follow-up. GS and WG were responsible for study implementation. ZS and JZ were involved in study design and implementation and performed the surgery, reviewed a draft of the manuscript, and approved the final draft. All authors contributed to the article and approved the submitted version. Acknowledgements The authors would like to thank Jiantao Jiang, Cheng Chen and Zhendong Li for helpful discussions on topics related to this work. References Glazebrook M, Daniels T, Younger A, et al. Comparison of health-related quality of life between patients with end-stage ankle and hip arthrosis[J]. J Bone Joint Surg Am. 2008;90(3):499–505. Valderrabano V, Horisberger M, Russell I, et al. Etiology of ankle osteoarthritis[J]. Clin Orthop Relat Res. 2009;467(7):1800–6. Didomenico LA, Gatalyak N. End-stage ankle arthritis: arthrodiastasis, supramalleolar osteotomy, or arthrodesis?[J]. Clin Podiatr Med Surg. 2012;29(3):391–412. Krahenbuhl N, Akkaya M, Deforth M, et al. Extraarticular Supramalleolar Osteotomy in Asymmetric Varus Ankle Osteoarthritis[J]. Foot Ankle Int. 2019;40(8):936–47. Sharrard WJ, Webb J. Supra-malleolar wedge osteotomy of the tibia in children with myelomeningocele[J]. J Bone Joint Surg Br. 1974;56B(3):458–61. Janssen G. 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Preoperative planning of multiapical frontal plane angular and bowing deformities of the femur and tibia[J]. Clin Orthop Relat Res, 1992(280): 65–71. Colin F, Bolliger L, Horn Lang T, et al. Effect of supramalleolar osteotomy and total ankle replacement on talar position in the varus osteoarthritic ankle: a comparative study[J]. Foot Ankle Int. 2014;35(5):445–52. Beijk I, Burgerhof J, De Vries AJ, et al. Is there an optimal degree of correction for ankle varus deformity after supramalleolar osteotomy? A systematic review[J]. Foot Ankle Surg. 2022;28(8):1139–49. Haraguchi N, Ota K, Tsunoda N, et al. Weight-bearing-line analysis in supramalleolar osteotomy for varus-type osteoarthritis of the ankle[J]. J Bone Joint Surg Am. 2015;97(4):333–9. Lee WC, Moon JS, Lee K, et al. Supramalleolar Osteotomy in Patients with Varus Ankle Osteoarthritis[J]. JBJS Essent Surg Tech. 2011;1(3):e13. Lee WC. Extraarticular Supramalleolar Osteotomy for Managing Varus Ankle Osteoarthritis, Alternatives for Osteotomy: How and Why?[J]. Foot Ankle Clin. 2016;21(1):27–35. Kim YS, Park EH, Koh YG, et al. Supramalleolar Osteotomy With Bone Marrow Stimulation for Varus Ankle Osteoarthritis: Clinical Results and Second-Look Arthroscopic Evaluation[J]. Am J Sports Med. 2014;42(7):1558–66. Song JH, Kang C, Kim TG, et al. Perioperative axial loading computed tomography findings in varus ankle osteoarthritis: Effect of supramalleolar osteotomy on abnormal internal rotation of the talus[J]. Foot Ankle Surg. 2021;27(2):217–23. Stukenborg-Colsman C, Ettinger S, Claassen L, et al. Conversion osteotomy for arthrosis of the ankle joint (supramalleolar and inframalleolar)-What can be expected? Critical review of the literature[J]. Unfallchirurg. 2022;125(3):189–95. Kim YS, Youn HK, Kim BS, et al. Arthroscopic evaluation of persistent pain following supramalleolar osteotomy for varus ankle osteoarthritis[J]. Knee Surg Sports Traumatol Arthrosc. 2016;24(6):1860–7. Tables Tables 1 to 5 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Tables.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4115368","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":285615525,"identity":"96dc52fa-7059-4fb8-bf65-dc9865e457f7","order_by":0,"name":"Cheng Wang","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Cheng","middleName":"","lastName":"Wang","suffix":""},{"id":285615526,"identity":"32e4c627-f672-4a2b-8a77-6c12893ac146","order_by":1,"name":"Xueqian Li","email":"","orcid":"","institution":"Huashan Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xueqian","middleName":"","lastName":"Li","suffix":""},{"id":285615527,"identity":"e4b29274-e965-4258-adc1-aee4d2188c67","order_by":2,"name":"Shaoling Fu","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shaoling","middleName":"","lastName":"Fu","suffix":""},{"id":285615528,"identity":"ca0df206-1e90-459c-886e-4889361e0759","order_by":3,"name":"Jiazheng Wang","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Jiazheng","middleName":"","lastName":"Wang","suffix":""},{"id":285615529,"identity":"061fb381-23d8-4902-b37f-ec6c50100030","order_by":4,"name":"Chenglin Wu","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chenglin","middleName":"","lastName":"Wu","suffix":""},{"id":285615530,"identity":"3aa4fd77-2f2f-41c5-a144-0e701d05214e","order_by":5,"name":"Guoxun Song","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Guoxun","middleName":"","lastName":"Song","suffix":""},{"id":285615531,"identity":"1c8d3d0e-d0d8-45e0-9bd7-20b8b5a6ea9d","order_by":6,"name":"Wenqi Gu","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Wenqi","middleName":"","lastName":"Gu","suffix":""},{"id":285615532,"identity":"564bdd70-b56c-49ba-b44c-e8ffeee50c74","order_by":7,"name":"Jieyuan Zhang","email":"","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":false,"prefix":"","firstName":"Jieyuan","middleName":"","lastName":"Zhang","suffix":""},{"id":285615533,"identity":"99212eeb-c4b1-42d5-b334-df5b22eb814a","order_by":8,"name":"Zhongmin Shi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA30lEQVRIie2PMQrCMBSGXynE5YlrFu0VIl0EPUy62MU6OzhEBDfpWkHwCgEvkBLoYourq7tDvYCaIjjWjIL5lpfh/+ALgMPxo6j7YzIwp3n7VoaXZ2QaAmh7xddIdCTeawslSE9cI/rxYXUuKCzGkehUqlVhqpL5npJEKk0olHEkcM7bFW8r1Y1hIsEo3sYUUmTtYeuuVMhpHIhGeVgoUHRljopxaMI8YaGw0ig7wYfmL+GIF3G4wdmXsLQ61nfxDIIsv17q5bifdsovYR+oAuDmEsu9oSfstw6Hw/FfvABs6Up0PfMZcgAAAABJRU5ErkJggg==","orcid":"","institution":"Shanghai Sixth People's Hospital","correspondingAuthor":true,"prefix":"","firstName":"Zhongmin","middleName":"","lastName":"Shi","suffix":""}],"badges":[],"createdAt":"2024-03-17 04:14:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4115368/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4115368/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":53882256,"identity":"6f3a7adb-196b-4f06-b76e-079b316597eb","added_by":"auto","created_at":"2024-04-01 18:01:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":478251,"visible":true,"origin":"","legend":"\u003cp\u003eA case of a 43-year-old male patient with varus ankle osteoarthritis, suffering from pain, deformity, and limited mobility for over 3 years. Physical examination revealed medial ankle joint inversion and dorsal flexion deformity, with significantly limited dorsiflexion range of motion. (A) Anterior view of both feet in standing position; (B) Posterior view of both feet in standing position; (C) Superior view of both feet in standing position; (D) Lateral view of both feet in squatting position.\u003c/p\u003e","description":"","filename":"Figure1Preoperativephysicalexamination.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/1425ecdd741396772833d339.png"},{"id":53881495,"identity":"b6b59e05-0224-4f42-95f6-8198218a546f","added_by":"auto","created_at":"2024-04-01 17:53:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":371487,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative radiographic imaging of the ankle joint in a treatment group patient with varus ankle osteoarthritis showed modified Takakura type Ⅲb varus deformity of the ankle and hindfoot.\u003c/p\u003e\n\u003cp\u003e(A) Preoperative weight-bearing anteroposterior X-ray of the ankle joint; (B) Preoperative lateral X-ray of the ankle joint; (C) Preoperative Saltzman view X-ray; (D) Preoperative weight-bearing lateral X-ray of the ankle joint; (E) Preoperative coronal CT scan of the ankle joint; (F) Preoperative sagittal CT scan of the ankle joint.\u003c/p\u003e","description":"","filename":"Figure2PreoperativeimagingexaminationFigure2Preoperativeimagingexamination.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/3650966bd18d94da028e6007.png"},{"id":53881497,"identity":"dac9cb51-2844-49ea-add3-a7951edaf2f3","added_by":"auto","created_at":"2024-04-01 17:53:22","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":655393,"visible":true,"origin":"","legend":"\u003cp\u003eSurgical procedure of supramalleolar osteotomy with Ilizarov technique for varus ankle osteoarthritis. (A) Installation of pre-designed 3D printed guide for supramalleolar osteotomy; (B, C) Fixation of the 3D printed guide with K-wires, followed by oblique osteotomy along the guide; (D) External fixation with Ilizarov ring fixator; (E, F) Anteroposterior and lateral views after installation of Ilizarov external fixation.\u003c/p\u003e","description":"","filename":"Figure3Surgicalprocedureoftreatmentgroup.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/3bccc9010dcc1493b90db1b8.png"},{"id":53881499,"identity":"02336165-3a13-46aa-b26e-a71e51105c78","added_by":"auto","created_at":"2024-04-01 17:53:22","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":336284,"visible":true,"origin":"","legend":"\u003cp\u003eImmediate postoperative X-ray after supramalleolar osteotomy with Ilizarov technique for varus ankle osteoarthritis. (A) Postoperative weight-bearing anteroposterior X-ray of the ankle joint; (B) Postoperative lateral X-ray of the ankle joint.\u003c/p\u003e","description":"","filename":"Figure4Immediatepostoperativeimagingexamination.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/2f152c04714a9e1d91700d48.png"},{"id":53881496,"identity":"70a1f505-53e4-4a45-b8fc-e41937635606","added_by":"auto","created_at":"2024-04-01 17:53:22","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":929908,"visible":true,"origin":"","legend":"\u003cp\u003eSurgical procedure of supramalleolar osteotomy with internal fixation for varus ankle osteoarthritis. (A) Installation of pre-designed 3D printed guide for supramalleolar osteotomy; (B) Fixation of the 3D printed guide with K-wires, followed by oblique osteotomy along the guide; (C) Installation of pre-designed distractor for gentle medial opening of the osteotomy site; (D) Use of a trial model to adjust the width; (E) Implantation of three cortical bone grafts and internal fixation with a locking plate; (F) Marking of the supramalleolar osteotomy site and direction above the tibiotalar joint level; (G) Performance of fibular osteotomy and adjustment of the position and length of the fibula; (H) Internal fixation of the fibular osteotomy with a locking plate; (I, J) Intraoperative fluoroscopy showing satisfactory positioning of the hindfoot alignment and restoration of ankle joint space.\u003c/p\u003e","description":"","filename":"Figure5Surgicalprocedureofcontrolgroup.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/a5f67614a3fa0ec7f91de2c8.png"},{"id":53881494,"identity":"6acbdf73-f999-44b5-a715-ddd7a89709b7","added_by":"auto","created_at":"2024-04-01 17:53:21","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":334354,"visible":true,"origin":"","legend":"\u003cp\u003ePostoperative follow-up after supramalleolar osteotomy with Ilizarov technique for varus ankle osteoarthritis, showing realignment of the ankle joint, restoration of joint space, joint congruity, and proper hindfoot alignment. (A) Posterior view of both feet in standing position at 3 months postoperative; (B) Anteroposterior X-ray of the ankle joint at 3 months postoperative; (C) Lateral X-ray of the ankle joint at 3 months postoperative; (D) Removal of external fixation at 6 months postoperative, anteroposterior X-ray of the ankle joint; (E) Removal of external fixation at 6 months postoperative, lateral X-ray of the ankle joint.\u003c/p\u003e","description":"","filename":"Figure6Postoperativefollowupoftreatmentgroup.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/0b30e87950a983f0e12453cb.png"},{"id":53881498,"identity":"3b9b98c9-bce6-45b5-95a9-01eda3d5d507","added_by":"auto","created_at":"2024-04-01 17:53:22","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":362634,"visible":true,"origin":"","legend":"\u003cp\u003ePostoperative follow-up after supramalleolar osteotomy with internal fixation for varus ankle osteoarthritis, showing realignment of the ankle joint and proper hindfoot alignment. (A) Anteroposterior X-ray of the ankle joint at 3 months postoperative; (B) Lateral X-ray of the ankle joint at 3 months postoperative; (C) Saltzman view X-ray at 3 months postoperative.\u003c/p\u003e","description":"","filename":"Figure7Postoperativefollowupofcontrolgroup.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/9f96fd5d09b8fec4e1657e63.png"},{"id":53881501,"identity":"f40d0078-97f7-4812-80c7-85b7a625db3d","added_by":"auto","created_at":"2024-04-01 17:53:22","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":575599,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of radiographic parameters between the treatment group preoperatively and postoperatively.\u003c/p\u003e","description":"","filename":"Figure8Comparisonofradiographicparameters.png","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/b804ced9f6843d5d600c95c6.png"},{"id":54746275,"identity":"18cc9c94-c657-46e3-933e-ca5e6128e086","added_by":"auto","created_at":"2024-04-16 07:23:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5668023,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/ae231aed-ae83-4ca7-9cc9-1a3b237d0b53.pdf"},{"id":53881492,"identity":"c40a48f6-4025-46d5-9d44-8304238fadf5","added_by":"auto","created_at":"2024-04-01 17:53:21","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":40954,"visible":true,"origin":"","legend":"","description":"","filename":"Tables.docx","url":"https://assets-eu.researchsquare.com/files/rs-4115368/v1/055286380f3356468332c194.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparative Efficacy of SMOT with Ilizarov Technique and SMOT with Internal Fixation in Varus Ankle Osteoarthritis","fulltext":[{"header":"Background","content":"\u003cp\u003eAnkle osteoarthritis (OA) is a degenerative condition characterized by bone spur formation, subchondral sclerosis, joint space narrowing, and varus/valgus deformity of the ankle joint, severely affecting patients\u0026rsquo; walking function and even leading to disability, affecting 1% of the global population\u0026nbsp;\u003csup\u003e[1,2]\u003c/sup\u003e. Ankle osteoarthritis can be classified into primary/idiopathic, secondary, and post-traumatic types, with post-traumatic ankle osteoarthritis being the most common, with 55% of patients presenting with varus deformity and only 8% with valgus deformity\u0026nbsp;\u003csup\u003e[2-4]\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eIn the 1970s and 1980s, some scholars first reported the application of supramalleolar osteotomy (SMOT) in the treatment of diseases with varus or valgus deformities of the ankle joint, such as nonunion after fractures, poliomyelitis, rheumatoid osteoarthritis, and hemophilic arthropathy \u003csup\u003e[5-10]\u003c/sup\u003e. This surgical technique can effectively correct deformities, restore joint alignment, preserve joint function, improve articular cartilage conditions, protect the epiphyseal plates in adolescents, delay the progression of OA, and postpone or avoid ultimate surgeries. It is suitable for patients aged \u0026lt;65 years, with higher body mass index (BMI), varus deformity \u0026gt;15\u0026deg; associated with ankle osteoarthritis, ankle fusion contraindication, subtalus deformities, and previous treatment or alternative options before ultimate surgery \u003csup\u003e[11-25]\u003c/sup\u003e. The Ilizarov technique can achieve deformity correction through bone and soft tissue traction methods and is suitable for patients with reduced bone quality, poor soft tissue conditions, poor coverage, leg length discrepancy, and unstable complex deformity osteotomy sites \u003csup\u003e[26-36]\u003c/sup\u003e. In 2003, Sen C et al. \u003csup\u003e[37]\u003c/sup\u003e reported the technique of percutaneous drilling osteotomy with Ilizarov Technique for SMOT, which effectively corrected foot and ankle deformities after 3-10 weeks of correction and distraction periods. In recent years, the method of SMOT combined with medial distraction arthroplasty has been introduced; however, there are no reports on the combination of SMOT with the Ilizarov technique. The purposes of this study were to (1) compare the clinical and radiographic outcomes between SMOT with Ilizarov technique and SMOT with internal fixation, and (2) assess the relationship between radiographic parameters and clinical outcomes after SMOT.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eStudy design and setting\u003c/p\u003e\n\u003cp\u003eInclusion criteria: (1) Takakura stage II-IIIb varus ankle osteoarthritis; (2) worsening pain and seriously impaired daily activities after 6 months of conservative treatment; (3) intact lateral tibial articular surface and \u0026lt;50% necrosis of the talus; (4) age 18-65 years with high activity demands; (5) follow-up time \u0026gt;2 year after surgery.\u003c/p\u003e\n\u003cp\u003eExclusion criteria: (1) Takakura stage IV ankle osteoarthritis with severe joint degeneration; (2) tibial double osteotomy procedure using internal fixation; (3) extensive bone and soft tissue defects after previous surgeries; (4) complications such as Charcot joint, rheumatoid osteoarthritis, ankle deformity, chronic infection, and comorbidities of diabetes, smoking, osteoporosis, and other vascular and neurological diseases.\u003c/p\u003e\n\u003cp\u003eParticipants\u003c/p\u003e\n\u003cp\u003eFrom August 2018 to June 2022, a total of 55 patients with varus ankle osteoarthritis were identified for this study, with 52 patients followed up after surgery and 3 lost follow-up. Among 52 patients, 19 patients in the SMOT with Ilizarov technique group (treatment group) and 33 patients in the SMOT with internal fixation group (control group) were included in this study. All patients underwent weight-bearing anteroposterior ankle X-rays, weight-bearing lateral ankle X-rays, Saltzman X-rays, ankle joint computer tomography (CT) scans, and measurements of tibial articular surface angle (TAS), tibial lateral surface angle (TLS), talar tilt (TT), tibiocrural angle (TC), tibial medial malleolar angle (TMM), hindfoot alignment angle (HAA), and modified Takakura stage by two experienced attending physicians (Figures 1, 2).\u003c/p\u003e\n\u003cp\u003eTreatment group: The treatment group consisted of 19 patients (19 feet), including 11 males and 8 females, with an average age of 44.21\u0026plusmn;14.27 years, a body mass index (BMI) of 25.94\u0026plusmn;4.41 kg/m2, a disease duration of 7.42\u0026plusmn;6.34 years, and a follow-up time of 37.63\u0026plusmn;10.57 months. According to the modified Takakura stage, there were 5 cases of stage II, 7 cases of stage IIIa, and 7 cases of stage IIIb. Control Group: The control group consisted of 33 patients (33 feet), including 18 males and 15 females, with an average age of 50.45\u0026plusmn;14.06 years, a BMI of 25.18\u0026plusmn;2.71 kg/m2, a disease duration of 8.38\u0026plusmn;6.36 years, and a follow-up time of 40.09\u0026plusmn;11.02 months. According to the modified Takakura stage, there were 12 cases of stage II, 15 cases of stage IIIa, and 6 cases of stage IIIb. There were no statistically significant differences in general data between the two groups (P \u0026gt; 0.05) (Table 1).\u003c/p\u003e\n\u003cp\u003ePreoperative Planning\u003c/p\u003e\n\u003cp\u003eWeight-bearing examination is necessary, and weight-bearing anteroposterior ankle X-rays, and weight-bearing lateral ankle X-rays play a key role in comparing the affected and unaffected ankles, assessing leg length discrepancy, pelvic tilt, hindfoot varus/valgus deformity, and knee varus/valgus deformity\u0026nbsp;\u003csup\u003e[38]\u003c/sup\u003e. Ankle joint CT scan has a good evaluation effect on ankle osteoarthritis that are difficult to determine by X-ray, and can accurately define the specific affected area of the ankle joint. In order to achieve complete adjustment of the foot and ankle deformities, this study performed medial wedge osteotomy at the CORA level\u0026nbsp;\u003csup\u003e[39]\u003c/sup\u003e. Varus ankle osteoarthritis often involve the coronal and/or sagittal planes, affecting multiple joints above and below the ankle, and affecting the overall lower limb alignment. Therefore, comprehensive identification and precise planning must be performed preoperatively\u0026nbsp;\u003csup\u003e[40]\u003c/sup\u003e. Preoperative planning at a level higher or lower than the deformity level will result in translation displacement. This study performed ankle joint thin-layer CT scanning with a slice thickness and interval of 0.625 mm. Arigin 3D pro (Shanghai Xinjian Medical Technology Co., Ltd.) was used to create a three-dimension (3D) reconstruction model to determine the center of rotation and angulation (CORA). Finite element mechanical analysis was used to create a digital model of varus ankle osteoarthritis, and parameters such as correction angle, osteotomy position, and size of wedge bone graft required for deformity correction were calculated based on the model. The target TAS was set at 90-92\u0026deg;, the target TLS was set at 80-85\u0026deg;, and the target TT was set at 0-4\u0026deg;.\u003c/p\u003e\n\u003cp\u003eSurgical procedure\u003c/p\u003e\n\u003cp\u003eThe patients were placed in a supine position under general anesthesia with the ipsilateral hip elevated and a tourniquet applied after routine disinfection. An incision was made in the anterior aspect of the ankle, which served as the observation and operation ports for arthroscopy. Arthroscopy was performed to explore and clean the synovial and fibrous scar tissue, bone spurs, and joint spaces. Complete release of the ankle joint was performed until dorsiflexion reached 20\u0026deg;.\u003c/p\u003e\n\u003cp\u003eSMOT was then performed. A longitudinal incision was made above the medial malleolus, exposing the osteotomy plane. A pre-designed 3D printed guide for SMOT was installed through the medial incision, and Kirschner wires were used to fix the guide. Osteotomy was performed at the designated site using an oscillating saw with guidance from the osteotomy guide. Care was taken to preserve the outer cortex of the tibia on the lateral side as a pivot point. Fluoroscopy was used to confirm the satisfactory position and correction of the osteotomy, and the guide was removed. Then a pre-designed distractor was gently applied to the medial osteotomy surface.\u003c/p\u003e\n\u003cp\u003eThe treatment group used Ilizarov ring fixator for external fixation. Kirschner wires and Schanz pins were inserted into the distal tibia, calcaneus, wedge bone of the midfoot, and metatarsals 1-5. A ring frame was installed in the middle and lower segments of the tibia and a semi-ring frame was installed in the foot. These frames were assembled using connecting rods. Traction was applied to the ankle joint, and the foot and ankle were maintained in a dorsiflexion-neutral position to allow postoperative joint movement. Intraoperative fluoroscopy was used to confirm that the ankle joint space had been stretched to 5mm (Figure 3, 4).\u003c/p\u003e\n\u003cp\u003eIn the control group, autogenous bone graft from the ipsilateral ilium or allograft cortical bone graft was used. These grafts were shaped according to a pre-designed trial model and implanted into the osteotomy site to fill the gap. An appropriate locking plate was selected to fix the distal tibia osteotomy site (Figure 5).\u003c/p\u003e\n\u003cp\u003ePreoperatively, the need for fibular osteotomy was determined based on fibular length and joint congruity. If necessary, fibular osteotomy was performed above the distal tibiofibular syndesmosis to adjust the position and length of the fibula. For patients with residual hindfoot varus deformity, calcaneal osteotomy was performed. For those with chronic ankle instability, a modified Brostrom procedure was performed intraoperatively. For patients with osteochondral lesions of the talus, the lesions was debrided using microfracture/bone marrow stimulation during arthroscopy. For patients with reduction of medial clear space, triangular ligament release was performed. For patients with limited dorsiflexion range of motion, per Silverskiod test results, either gastrocnemius recession or Achilles tendon lengthening was performed. Fluoroscopy was used to confirm restoration of the tibiofibular joint space and correction of the hindfoot alignment.\u003c/p\u003e\n\u003cp\u003eAuxiliary procedures in this study included a modified Brostrom procedure in 38 cases, gastrocnemius recession or Achilles tendon lengthening in 32 cases, iliac bone grafting in 32 cases, arthroscopic microfracture in 19 cases, calcaneal osteotomy in 16 cases, posterior ankle arthroscopy in 2 cases, and LARS ligament reconstruction in 1 case.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAftercare and follow-up routine\u003c/p\u003e\n\u003cp\u003eIn the treatment group, patients were instructed to perform joint distraction with the Ilizarov ring fixator twice a day, with a distraction rate of 0.5mm each time, for at least 3 months. Weight-bearing and ankle joint motion were prohibited for the first 6 weeks after surgery. The Ilizarov ring fixator was removed 3-4 months postoperatively, and ankle joint manipulation was performed under anesthesia to prevent joint adhesion. After the removal of the Ilizarov ring fixator, a inflatable walking boot was immediately used to allow partial weight-bearing for 1 month. After confirming the bony union of the osteotomy site through imaging examination, full weight-bearing could start. Following the removal of internal fixation, physiotherapy was continued for 2 months to improve range of motion, lower limb strength, and proprioception (Figure 6).\u003c/p\u003e\n\u003cp\u003eIn the control group, conventional support fixation was applied using an inflatable walking boot or short leg cast after surgery. Leg elevation training, active toe and ankle joint exercises could be performed from the second day onwards. Weight-bearing was prohibited within the first 6 weeks, and after confirming the formation of callus at 6 weeks postoperatively, the patients were allowed to bear weight with the support. After confirming the bony union of the osteotomy site through imaging examination, full weight-bearing could start (Figure 7).\u003c/p\u003e\n\u003cp\u003eOutcome measures\u003c/p\u003e\n\u003cp\u003eOutcome measurements included the AOFAS ankle-hindfoot score, AOS, VAS, ROM, as well as radiographic parameters including TAS, TLS, TT, TC, TMM, HAA, and modified Takakura grade. The AOFAS ankle-hindfoot score assesses pain, function, gait, range of motion, stability, and alignment, with a maximum score of 100. Scores of 90-100 are considered excellent, 75-89 good, 50-74 fair, and below 50 poor. VAS score ranges from 0 to 10, indicating the severity of pain. To analyze changes in imaging grading, a quantitative scoring system was used, with scores of 2, 3, 4, and 5 assigned to modified Takakura grades II, IIIa, IIIb, and IV, respectively. Complications were also observed.\u003c/p\u003e\n\u003cp\u003eStatistical Analysis\u003c/p\u003e\n\u003cp\u003eStatistical analysis was performed using SPSS 26.0 software. The Shapiro-Wilk test was used to assess the normality of the data. Normally distributed continuous variables are presented as mean \u0026plusmn; standard deviation (x̄ \u0026plusmn; s), and paired-sample \u003cem\u003et\u003c/em\u003e-tests were used to compare preoperative and final follow-up measurements within each group. Independent-sample \u003cem\u003et\u003c/em\u003e-tests were used to compare measurements between the two groups. Skewed distributed continuous variables are presented as M (Q1, Q3), and Wilcoxon signed-rank tests were used to compare preoperative and final follow-up measurements within each group. Wilcoxon rank-sum tests were used to compare measurements between the two groups. Spearman\u0026rsquo;s correlation analysis was used to assess the correlation between radiographic parameters (TAS, TT, TLS, TT, TC, TMM, HAA, modified Takakura stage) and clinical outcomes (VAS and AOFAS scores) at the final follow-up. A p-value \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eGeneral information comparison\u003c/p\u003e\n\u003cp\u003eAll 52 patients were followed up after surgery, with a mean follow-up time of 37.63\u0026plusmn;10.57 months in the treatment group and 40.09\u0026plusmn;11.02 months in the control group. \u0026nbsp;In the control group, wound healing was classified as Grade I in 50 patients, while 2 patients developed wound infections at 2 and 3 months postoperatively, respectively. The infections were successfully treated with debridement, vacuum-sealing drainage (VSD), local dressing changes, and intravenous antibiotics. In the treatment group, all wounds healed as Grade I, and the Ilizarov ring fixator was removed at an average of 13.86\u0026plusmn;1.68 weeks with no cases of wound infection or need for additional surgeries. Neither group experienced complications such as ankle osteoarthritis progression, deformity recurrence, or nonunion.\u003c/p\u003e\n\u003cp\u003eClinical efficacy comparison\u003c/p\u003e\n\u003cp\u003eCompared to preoperative values, both groups showed statistically significant improvements (P \u0026lt; 0.001) in AOFAS ankle-hindfoot score, AOS, VAS, and ROM at the final follow-up. Except for TLS, both groups exhibited statistically significant improvements (P \u0026lt; 0.001) in radiographic parameters including TAS, TT, TC, TMM, and HAA, as well as modified Takakura grade (Table 2).\u003c/p\u003e\n\u003cp\u003eThere were no statistically significant differences (P \u0026gt; 0.05) between the two groups in AOFAS score and AOS function score at both preoperative and final follow-up. However, the treatment group showed significantly better improvement in AOS pain score (P = 0.011) and ROM (P = 0.024) compared to the control group, with statistical significance. Regarding radiographic parameters, there were no statistically significant differences (P \u0026gt; 0.05) between the two groups in TAS, TLS, TT, TC, TMM, and modified Takakura grade. However, the improvement in HAA (P = 0.031) was significantly better in the treatment group compared to the control group (Table 3).\u003c/p\u003e\n\u003cp\u003eAccording to the modified Takakura stage, in the treatment group, all 5 cases of Grade II improved to Grade I, 5 cases of Grade IIIa improved to Grade I, 2 cases improved to Grade II, and all 7 cases of Grade IIIb improved to Grade II. In the control group, 2 cases of Grade II improved to Grade 0, 10 cases of Grade IIIa improved to Grade I, 9 cases improved to Grade I, 6 cases improved to Grade II, 5 cases of Grade IIIb improved to Grade II, and 1 case improved to Grade IIIa (Table 4, 5).\u003c/p\u003e\n\u003cp\u003eSpearman correlation analysis showed that at the final follow-up, there were statistically significant correlations (P \u0026lt; 0.05) between the changes in TT and TC and the final AOFAS ankle-hindfoot score, VAS, and AOS pain score. \u0026Delta;TT was positively correlated with the AOFAS ankle-hindfoot score (r=0.336) and negatively correlated with the VAS (r=-0.297) and AOS pain score (r=-0.358). \u0026Delta;TC was positively correlated with the AOFAS ankle-hindfoot score (r=0.299) and negatively correlated with the VAS (r=-0.278) and AOS pain score (r=-0.348) (Figure 8, Table 6).\u003c/p\u003e\n\u003cp\u003eComplications\u003c/p\u003e\n\u003cp\u003eIn the control group, 2 cases of wound infection occurred at 2 and 3 months postoperatively, respectively. These infections were managed with soft tissue debridement, VSD, short-term local dressing changes, and intravenous antibiotics, resulting in Grade II wound healing. In the treatment group, all wounds healed as Grade I, and there were no cases of wound infection or need for additional surgeries. Early removal of fixation, pin tract infections, and soft tissue irritation were not observed in either group. Neither group experienced complications such as ankle osteoarthritis progression, deformity recurrence, nonunion, delayed healing, or tendon vascular nerve injury.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eBackground and rationale\u003c/p\u003e\n\u003cp\u003eIn the surgical treatment of varus ankle osteoarthritis, arthroscopic debridement, medial distraction arthroplasty, and SMOT have gained wide attention for their advantages in pain relief and increased ROM without sacrificing the ankle joint. In recent years, numerous clinical studies on SMOT have consistently demonstrated its effective deformity correction, satisfactory outcomes, and good clinical efficacy, making it an increasingly preferred option for joint-preserving surgery in patients with varus ankle osteoarthritis\u0026nbsp;\u003csup\u003e[11-25]\u003c/sup\u003e. SMOT techniques include closed wedge, open wedge, dome osteotomy, tractional, rotational, and stepped osteotomy, often combined with other surgical approaches. Open wedge SMOT offers advantages such as restoration of leg length, correction of varus angulation, inherent stability, and the ability to correct minor lateral deformities due to its translational properties. Moreover, it exhibits faster bone healing compared to closed wedge osteotomy\u0026nbsp;\u003csup\u003e[16,18,41-45]\u003c/sup\u003e. However, open wedge osteotomy carries risks of delayed union, nonunion, and graft rejection, as well as increased tension on the posterior tibial neurovascular bundle, making it less suitable for patients with diabetes, rheumatoid osteoarthritis, smoking, or vascular diseases\u0026nbsp;\u003csup\u003e[35]\u003c/sup\u003e. The fixation method during SMOT should consider the surgeon\u0026rsquo;s experience, patients\u0026rsquo; skin condition, ankle joint translational and rotational deformities, and available bone stock\u0026nbsp;\u003csup\u003e[16]\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eClinical Outcomes of SMOT with Ilizarov Technique\u003c/p\u003e\n\u003cp\u003eExternal fixation is necessary for patients with complex deformities of ankle osteoarthritis who are not suitable for one-stage correction and require gradual correction \u003csup\u003e[45,46]\u003c/sup\u003e. Compared to internal fixation methods, external fixation has the greatest advantage in gradually correcting complex multiplanar deformities, which is beneficial for precise correction of severe residual deformities and leg length discrepancies, as well as improving joint stiffness through distraction, vegetating and stimulating chondrocytes \u003csup\u003e[34,47-50]\u003c/sup\u003e. Large-scale studies and long-term results have shown that patients with severe post-traumatic ankle osteoarthritis benefit from joint distraction in terms of symptom relief and improved function \u003csup\u003e[3,51,52]\u003c/sup\u003e. In 1995, Van Valburg et al. \u003csup\u003e[46]\u003c/sup\u003e first used Ilizarov ring fixators for gradual distraction before arthrodesis or arthroplasty. The Ilizarov ring fixator can be configured according to the deformity requirements, but it has a steep learning curve \u003csup\u003e[53,54]\u003c/sup\u003e. Subsequent studies by Eidelman et al. \u003csup\u003e[55]\u003c/sup\u003e described the use of the Taylor spatial frame for distal tibial deformity correction, which facilitated the surgical procedure of distal tibial osteotomy. Elomrani et al. \u003csup\u003e[56]\u003c/sup\u003e demonstrated that 41 out of 55 patients with distal tibial deformities achieved good or excellent surgical outcomes. Horn et al.\u003csup\u003e[47]\u003c/sup\u003e reported that in patients treated with SMOT, correction of tibial deformities using a six-axis circular external fixator was especially effective for complex oblique deformities, soft tissue injuries, and patients with previous surgeries or infections. Zhao et al \u003csup\u003e[57,58]\u003c/sup\u003e initially applied the combination of SMOT and medial distraction arthroplasty in a case of Takakura Grade IIIb varus ankle osteoarthritis with a TT angle of 21.3\u0026deg;, and subsequently conducted a retrospective controlled study demonstrating the effectiveness of this combination for large TT angles in varus ankle osteoarthritis. In this study, SMOT with Ilizarov technique in the treatment group showed significant advantages in correcting bony and soft tissue deformities, leading to better restoration of joint mobility and more satisfactory clinical outcomes. Although the treatment group had a longer operative time, the average duration was still within an acceptable range, considering the potential impact of the learning curve. Additionally, there were no statistically significant differences between the two groups in terms of fluoroscopy time and blood loss.\u003c/p\u003e\n\u003cp\u003eRadiographic Outcomes of SMOT with Ilizarov Technique\u003c/p\u003e\n\u003cp\u003ePrevious studies have shown that SMOT can improve TAS, TC, and TMM\u0026nbsp;\u003csup\u003e[18,23,59-62]\u003c/sup\u003e. Some scholars have suggested correcting TAS within the normal range\u0026nbsp;\u003csup\u003e[17,63-65]\u003c/sup\u003e, while others have recommended a slight overcorrection or the use of calcaneal osteotomy to correct residual deformities\u0026nbsp;\u003csup\u003e[18,41,59,66-70]\u003c/sup\u003e. However, the optimal correction angle for SMOT remains unclear\u0026nbsp;\u003csup\u003e[71]\u003c/sup\u003e. Traditional SMOT based on TAS has led to significant changes in the mechanical axis of the ankle joint, indicating that TAS is not a reliable indicator for determining the correction angle of SMOT\u0026nbsp;\u003csup\u003e[72]\u003c/sup\u003e. We propose correcting TAS to approximately 95\u0026deg;, which corresponds to a 5\u0026deg; external rotation of the ankle joint. Excessive external rotation does not necessarily improve the correction of TT. Tanaka et al.\u0026nbsp;\u003csup\u003e[59,66]\u003c/sup\u003e suggest that SMOT cannot achieve Grade I in cases with a TT angle greater than 10\u0026deg; or Takakura Grade IIIb deformity, resulting in less satisfactory clinical outcomes. Lee et al.\u0026nbsp;\u003csup\u003e[73,74]\u003c/sup\u003e found that SMOT is not suitable for severe ankle osteoarthritis with significant TT and joint space narrowing, and they identified a preoperative TT angle greater than 7.3\u0026deg; as the optimal predictive indicator for high postoperative TT angles. Tanaka et al.\u0026nbsp;\u003csup\u003e[59,66]\u003c/sup\u003e compared clinical outcomes with radiographic grading based on the modified Takakura stage and concluded that clinical outcomes did not improve in cases of Grade IIIb ankle osteoarthritis. Kim et al.\u0026nbsp;\u003csup\u003e[75]\u003c/sup\u003e included only Grade II and IIIb patients in their study and found that postoperative radiographic results did not significantly influence clinical outcomes. However, Hongmou et al.\u0026nbsp;\u003csup\u003e[60]\u003c/sup\u003eand Lai et al.\u0026nbsp;\u003csup\u003e[23]\u003c/sup\u003e reported good functional outcomes even in cases with high TT and Takakura Grade IIIb deformity. In our study, there were no statistically significant differences between preoperative and postoperative TLS, possibly due to the presence of anterior osteophytes in varus ankle osteoarthritis, which may interfere with TLS measurements. Both groups showed statistically significant improvements in TAS, TT, TC, TMM, and modified Takakura grade at the final follow-up compared to preoperative values. There were no statistically significant differences between the two groups in TAS, TLS, TT, TC, TMM, and modified Takakura grade at the final follow-up, but the treatment group showed a statistically significant advantage in terms of HAA improvement compared to the control group. These results may demonstrate the corrective ability of SMOT with Ilizarov technique in realigning the hindfoot alignment and rearranging the foot and ankle through joint distraction and soft tissue manipulation. Additionally, the modified Takakura grade at the final follow-up showed that the control group achieved a reduction in modified Takakura grade below Grade I in 52.63% of patients, while the treatment group achieved a reduction below Grade I in 63.64% of patients, suggesting the advantage of SMOT with Ilizarov technique in modifying the stage of varus ankle osteoarthritis and delaying joint degeneration. Although not statistically significant, the TT improvement in the treatment group was somewhat better than that in the control group. Furthermore, 89.47% (17/19) of patients in the treatment group achieved a return to normal TT levels, compared to only 78.79% (26/33) in the control group. However, this needs to be further validated through larger sample size and longer-term follow-up.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe Relationship between Radiographic Parameters and Clinical Outcomes after SMOT\u003c/p\u003e\n\u003cp\u003eAdditionally, this study verified through Spearman correlation analysis that there is a statistically significant correlation between \u0026Delta;TT, \u0026Delta;TC, and AOFAS ankle-hindfoot scores, VAS, and AOS pain scores at the final follow-up. The absolute values of the correlation coefficients were all within the range of 0.2 to 0.4, indicating a weak positive correlation between \u0026Delta;TT, \u0026Delta;TC, and AOFAS ankle-hindfoot scores, as well as a weak negative correlation between \u0026Delta;TT, \u0026Delta;TC, and VAS scores and AOS pain scores. This suggests that improvements in TT and TC during SMOT may lead to better clinical outcomes.\u003c/p\u003e\n\u003cp\u003eSurgical Technique and Points\u003c/p\u003e\n\u003cp\u003eCurrently, the talar tilt and abnormal internal rotation caused by varus ankle osteoarthritis have gained increasing attention. Scholars generally believe that ankle osteoarthritis is not only a bone deformity that leads to joint malalignment but also a soft tissue imbalance \u003csup\u003e[24,57,58,76,77]\u003c/sup\u003e. After three months of opening the medial side of the ankle joint, the internal and external soft tissue balance will be partially restored, and the TT angle will be further corrected \u003csup\u003e[57]\u003c/sup\u003e. In our study, correction started on the first day after surgery, with a correction rate of 1 mm/day. The average external fixation time was 13.86\u0026plusmn;1.68 weeks, and modular adjustments were made to achieve multi-level, multi-plane, and multi-stage corrections based on individual patient needs and specific conditions. To the best of our knowledge, this is the first retrospective case-control study comparing the outcomes of SMOT with Ilizarov technique and SMOT with internal fixation. Our study believes that correcting the soft tissue imbalance is crucial for complete correction of ankle joint deformities when faced with excessive TT angles in varus ankle osteoarthritis. The Ilizarov circular external fixator cannot correct the bony deformity but can maintain hindfoot alignment, release the lateral structures, and achieve complete correction in patients with varus ankle osteoarthritis when combined with SMOT. After SMOT and internal fixation, there may still be postoperative hindfoot rotation deformities, and excessive stress on the medial side of the ankle joint during weight-bearing. Progressive correction using Ilizarov technique can also minimize the risk of vascular and nerve injuries. When planning for SMOT, all accompanying issues related to medial and lateral soft tissues and periarticular deformities should be thoroughly addressed in the preoperative planning. In conclusion, Ilizarov technique is beneficial for restoring ankle joint mobility, and SMOT is effective in correcting internal rotation deformities of the ankle joint. Both SMOT and Ilizarov technique require high technical skills from surgeons, necessitating extensive and meticulous preoperative planning and a longer learning curve.\u003c/p\u003e\n\u003cp\u003eAccording to the current literature, the incidence of progressive degenerative changes in the ankle joint after SMOT for ankle osteoarthritis is as high as 25%, and the incidence of infections and wound healing issues is as high as 22% \u003csup\u003e[19]\u003c/sup\u003e. In the control group of this study, there were 2 cases of postoperative wound infections, which were treated with debridement and negative pressure wound therapy (VSD). Short-term local dressing changes and intravenous antibiotics were used for infection prevention, and all wounds healed at stage II. Adhesions, synovitis, and soft tissue impingement can cause persistent pain after SMOT \u003csup\u003e[78]\u003c/sup\u003e. Comprehensive exploration and cleaning were performed using arthroscopy in this study, potentially avoiding most cases of postoperative persistent pain.\u003c/p\u003e\n\u003cp\u003eLimitations\u003c/p\u003e\n\u003cp\u003eThe limitations of this study include: (1) the retrospective study design may lead to bias in data accuracy, so two experienced attending physicians were specifically responsible for measuring the parameters; (2) the follow-up time was short, and the sample size was small, resulting in type II statistical errors. Long-term follow-up is needed to further assess the mid- to long-term efficacy, but early results have preliminarily confirmed the favorable effects of SMOT with Ilizarov technique in relieving pain, correcting deformities, and improving function; (3) this study simultaneously combined several auxiliary surgeries, resulting in a certain degree of heterogeneity, which may lead to confounding effects in the evaluation of patients\u0026rsquo; function and efficacy; (4) due to the subjective difficulties of Second Look patients, it was not possible to observe the internal condition of the joint, thus further research is needed for validation.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn conclusion, this study preliminarily demonstrates that SMOT with Ilizarov technique is a more effective treatment option for varus ankle osteoarthritis compared to SMOT with internal fixation. For moderate to severe varus ankle osteoarthritis, SMOT with Ilizarov technique has satisfactory efficacy in relieving pain, correcting deformities, and improving function. It not only corrects both bony and soft tissue deformities but also improves joint mobility better than SMOT with internal fixation, while minimizing postoperative complications. During SMOT, improvements in TT and TC may lead to better clinical outcomes. Further prospective studies with larger sample sizes are needed to validate and expand these findings.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eSMOT, supramalleolar osteotomy\u003c/p\u003e\n\u003cp\u003eAOFAS, American Orthopaedic Foot and Ankle Society\u003c/p\u003e\n\u003cp\u003eAOS, ankle osteoarthritis score\u003c/p\u003e\n\u003cp\u003eVAS, visual analogue scale\u003c/p\u003e\n\u003cp\u003eROM, range of motion\u003c/p\u003e\n\u003cp\u003eTAS, tibial articular surface angle\u003c/p\u003e\n\u003cp\u003eTLS, tibial lateral surface angle\u003c/p\u003e\n\u003cp\u003eTT, talar tilt\u003c/p\u003e\n\u003cp\u003eTC, tibiocrural angle\u003c/p\u003e\n\u003cp\u003eTMM, tibial medial malleolar angle\u003c/p\u003e\n\u003cp\u003eHAA, hindfoot alignment angle\u003c/p\u003e\n\u003cp\u003eOA, ankle osteoarthritis\u003c/p\u003e\n\u003cp\u003eBMI, body mass index\u003c/p\u003e\n\u003cp\u003eCT, computer tomography\u003c/p\u003e\n\u003cp\u003e3D, three-dimension\u003c/p\u003e\n\u003cp\u003eVSD, vacuum-sealing drainage\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics Approval and Consent to Participate\u003c/p\u003e\n\u003cp\u003eThis study was approved by Ethics Committee of Shanghai Sixth People\u0026apos;s Hospital，conducted in accordance with\u0026nbsp;the ethical standards in the 1964 Declaration of Helsinki, approved by the institutional ethics review board, and obtained written informed consent from all participants. The ethics approval number was 2020-135, and the clinical trail registration number was ChiCTR1900020579.\u003c/p\u003e\n\u003cp\u003eConsent to Publish\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003c/p\u003e\n\u003cp\u003eData Availability Statement\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003eCompeting Interests\u003c/p\u003e\n\u003cp\u003eAll authors declare no conflicts of interest.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis research was funded by Bio-medical Engineering Program of Shanghai Jiao Tong University Star Plan (YG2022ZD018); Key Research and Development Program of National Ministry of Science and Technology (2022YFC2009500).\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; Contributions\u003c/p\u003e\n\u003cp\u003eCWa, XL and SF were responsible for conceiving and designing the experiments, statistical analysis, and drafting the manuscript. JW and CWu were involved in collecting patient data and follow-up. GS and WG were responsible for study implementation. ZS and JZ were involved in study design and implementation and performed the surgery, reviewed a draft of the manuscript, and approved the final draft. All authors contributed to the article and approved the submitted version.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank Jiantao Jiang, Cheng Chen and Zhendong Li for helpful discussions on topics related to this work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGlazebrook M, Daniels T, Younger A, et al. Comparison of health-related quality of life between patients with end-stage ankle and hip arthrosis[J]. J Bone Joint Surg Am. 2008;90(3):499\u0026ndash;505.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValderrabano V, Horisberger M, Russell I, et al. Etiology of ankle osteoarthritis[J]. 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Foot Ankle Surg. 2022;28(8):1139\u0026ndash;49.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaraguchi N, Ota K, Tsunoda N, et al. Weight-bearing-line analysis in supramalleolar osteotomy for varus-type osteoarthritis of the ankle[J]. J Bone Joint Surg Am. 2015;97(4):333\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee WC, Moon JS, Lee K, et al. Supramalleolar Osteotomy in Patients with Varus Ankle Osteoarthritis[J]. JBJS Essent Surg Tech. 2011;1(3):e13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee WC. Extraarticular Supramalleolar Osteotomy for Managing Varus Ankle Osteoarthritis, Alternatives for Osteotomy: How and Why?[J]. Foot Ankle Clin. 2016;21(1):27\u0026ndash;35.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim YS, Park EH, Koh YG, et al. Supramalleolar Osteotomy With Bone Marrow Stimulation for Varus Ankle Osteoarthritis: Clinical Results and Second-Look Arthroscopic Evaluation[J]. Am J Sports Med. 2014;42(7):1558\u0026ndash;66.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSong JH, Kang C, Kim TG, et al. Perioperative axial loading computed tomography findings in varus ankle osteoarthritis: Effect of supramalleolar osteotomy on abnormal internal rotation of the talus[J]. Foot Ankle Surg. 2021;27(2):217\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStukenborg-Colsman C, Ettinger S, Claassen L, et al. Conversion osteotomy for arthrosis of the ankle joint (supramalleolar and inframalleolar)-What can be expected? Critical review of the literature[J]. Unfallchirurg. 2022;125(3):189\u0026ndash;95.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim YS, Youn HK, Kim BS, et al. Arthroscopic evaluation of persistent pain following supramalleolar osteotomy for varus ankle osteoarthritis[J]. Knee Surg Sports Traumatol Arthrosc. 2016;24(6):1860\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 5 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"SMOT, Ilizarov, external fixation, ankle osteoarthritis, varus, surgery","lastPublishedDoi":"10.21203/rs.3.rs-4115368/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4115368/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eVarus ankle osteoarthritis is a degenerative condition characterized by varus deformity of the ankle joint, severely damaging patients\u0026rsquo; quality of life. supramalleolar osteotomy (SMOT) has become one of the most commonly used joint-preserving surgeries for the treatment of varus ankle osteoarthritis. Both SMOT with Ilizarov technique and SMOT with internal fixation can be employed to correct varus deformity; however, there is limited literature comparing the efficacy of these two methods.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe retrospectively analyzed the clinical data of 52 patients (52 feet) who underwent SMOT for varus ankle osteoarthritis between August 2018 and June 2022. The patients were divided into two groups based on the surgical approach: the SMOT with Ilizarov technique group (treatment group, n\u0026thinsp;=\u0026thinsp;19, 19 feet) and the SMOT with internal fixation group (control group, n\u0026thinsp;=\u0026thinsp;33, 33 feet). Clinical evaluation parameters, including the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Ankle Osteoarthritis Score (AOS), Visual Analogue Scale (VAS), and ankle joint range of motion (ROM), were compared between the two groups. Radiographic parameters, including tibial articular surface angle (TAS), tibial lateral surface angle (TLS), talar tilt (TT), tibiocrural angle (TC), tibial medial malleolar angle (TMM), hindfoot alignment angle (HAA), and modified Takakura stage, were also compared. Furthermore, complications such as infection, delayed healing, and nonunion were recorded and compared between the two groups.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003ePreliminary results showed that both SMOT with Ilizarov technique and SMOT with internal fixation significantly improved clinical scores and radiographic parameters. All 52 patients (52 feet) were followed up for an average of 39.19\u0026thinsp;\u0026plusmn;\u0026thinsp;10.82 weeks. In the postoperative period, 50 patients achieved grade I wound healing, while 2 patients in the control group experienced wound infection. Both groups showed statistically significant improvements in AOFAS ankle-hindfoot score, AOS, VAS, and ROM at the last follow-up (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). TAS, TT, TC, TMM, HAA, and modified Takakura stage also significantly improved compared to preoperative measurements (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). At the last follow-up, no statistically significant differences were observed between the two groups in terms of AOFAS ankle-hindfoot score, AOS functional score, VAS, TAS, TLS, TT, TC, TMM, or modified Takakura stage. However, the treatment group demonstrated significantly greater improvements in AOS pain score (P\u0026thinsp;=\u0026thinsp;0.011), ROM (P\u0026thinsp;=\u0026thinsp;0.024), and HAA (P\u0026thinsp;=\u0026thinsp;0.031) compared to the control group. Correlations were observed between the changes in TT, TC, and the last follow-up AOFAS ankle-hindfoot score, VAS, and AOS pain score in the radiographic results.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis study suggests preliminarily that SMOT with Ilizarov technique is a more effective treatment option for varus ankle osteoarthritis compared to SMOT with internal fixation. For moderate to severe cases of varus ankle osteoarthritis, SMOT with Ilizarov technique provides satisfactory outcomes by correcting both bone and soft tissue deformities, achieving better restoration of ROM, superior correction of hindfoot alignment, and minimizing postoperative complications compared to SMOT with internal fixation. Additionally, it minimizes postoperative complications. Improvements in TT and TC during SMOT may lead to better clinical outcomes.\u003c/p\u003e\u003ch2\u003eTrial registration:\u003c/h2\u003e \u003cp\u003eThe registration number was ChiCTR1900020579, and date of registration was 2019-01-09.\u003c/p\u003e","manuscriptTitle":"Comparative Efficacy of SMOT with Ilizarov Technique and SMOT with Internal Fixation in Varus Ankle Osteoarthritis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-01 17:53:16","doi":"10.21203/rs.3.rs-4115368/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e263168a-40db-42b7-99d2-6148cd0edc27","owner":[],"postedDate":"April 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-04-16T07:15:00+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-01 17:53:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4115368","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4115368","identity":"rs-4115368","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}