The Radiographic Support for Distal Tibia Medial Opening-Wedge Osteotomy with Fibular Valgization Osteotomy for Medial Ankle Osteoarthritis

Abstract

Category: Ankle; Ankle Arthritis Introduction/Purpose: Supramalleolar osteotomy (SMO) has recently been accepted as the major surgical option for treating painful asymmetric ankle arthritis. The effectivenss of additional fibular valgization osteotomy during SMO procedure is still controversial. This study aimed to evaluate radiological and clinical outcomes of medial compartment ankle osteoarthritis (OA) after SMO with fibular valgization osteotomy. Also, the study is aimed to describe the radiographic support for the SMO with additional fibular osteotomy in relieving the medial ankle pain. Methods: The study is based on 45 cases of medial compartment ankle arthritis (43 patients) with moderate to severe medial ankle pain (at least 1-year follow-up). SMO and fibular valgization oblique osteotomy was performed concomitantly in 37 ankles (82.2%). As for the functional evaluation, visual analogue scale (VAS) pain scores, American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores and patient satisfaction were evaluated. On radiographs, tibial anterior surface angles (TAS), tibial lateral surface angles (TLS), and talar tilt angles (TT) were measured and the severity of ankle OA was classified by the Takakura stage. The evaluation of the effect of fibular valgization osteotomy entailed a comparison of new radiological measurement (medial clear space gap distance and talus center migaration distance) between two groups: Group 1 (with 37 cases of SMO with fibular valgization osteotomy) and Group 2 (with 8 cases of SMO without fibular valgization osteotomy). Results: The mean VAS pain score decreased from preoperative 6.5 to postoperative 1.3, and AOFAS score significantly improved from preoperative 60.4 to 88.3 at final follow-up. 91 percent (41 ankles) of the patients were satisfied with surgery. Mean TAS improved from preoperative 83.8° to postoperative 94.9° and TLS from 78.5° to 82.0°. 23 of 30 Takakura stage IIIa cases (77%) and 3 of 7 stage IIIb cases (42%) improved to stage II after SMO at final follow-up. Mean fibular valgization osteotomy angle was 12.4°. Medial gutter space gap distance improved from preoperative 0.7mm to postoperative 2.10mm. Talus center migration distance improved from -0.53mm to 2.03mm. Both radiologic parameters showed statistically significant differences between two groups, but there was no correlation between radiologic parameters and clinical outcomes. Conclusion: SMO for the patients with painful medial compartment ankle OA achieved favorable clinical and radiological outcomes. Also, high patient satisfaction (91%) as well as the improvement of Takakura stage was observed. SMO with additional fibular valgization osteotomy yielded widening of medial gutter space and recovery of talus center. Therefore, additional fibular valgization osteotomy during SMO could be optimal surgical option for the recovery of normal ankle mechanical axis.