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

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.