Radiologic Factors Affecting Ankle Pain Before and After Total Knee Arthroplasty for the Varus Osteoarthritic Knee

The aim of the present study was to evaluate the radiologic factors related to ankle pain before and after total knee arthroplasty (TKA) among patients with a varus osteoarthritic knee. Fifty-five patients (65 ankles) with a varus osteoarthritic knee who had undergone TKA and were followed up for >24 months were enrolled. For clinical assessment, the visual analog scale for pain and the American Orthopaedic Foot and Ankle Society ankle-hindfoot scale were used. For radiologic assessment, the mechanical axis deviation angle, talar tilt, tibial anterior surface angle, distal medial clear space, medial tibiotalar joint space, frontal tibial ground angle, and hindfoot alignment view angle were measured. The patients with ankle pain before TKA (11 ankles) had a larger hindfoot alignment view angle (9.2° ± 2.6°) than that of patients without ankle pain before TKA (54 ankles; 5.5° ± 4.8°; p = .007). The patients with newly developed ankle pain or experienced an aggravation of existing pain after TKA (8 ankles) had a significantly larger degree of residual varus (5.1° ± 2.1°) than did the patients without ankle pain before and after TKA or those with ankle pain before surgery. However, the severity of the pain was not different during the follow-up period (52 ankles; 1.6° ± 2.5°; p = .001). The results of the present study showed that residual varus deformity was associated with ankle pain after TKA. Surgeons should perform evaluations of the ankles of patients who complain of pain before and after TKA and should give careful attention to the correction of alignment during TKA.