Radiographic Evaluation of the Association between Foot Deformities and Ankle Medial Osteoarthritis.

BACKGROUND: Foot deformities can cause abnormal biomechanics of the ankle joint and the development of osteoarthritis. It was hypothesized that foot deformities would be related to medial ankle osteoarthritis, and this study investigated this relationship using radiographic measurements.

METHODS: Seventy-six ankles of 76 patients (32 men and 44 women; mean age, 69.0 years) with medial ankle osteoarthritis were included. Eleven radiographic measurements evaluated ankle joint orientation (tibial plafond inclination [TPI], medial distal tibial angle [MDTA], and anterior distal tibial angle [ADTA]), ankle joint incongruency (tibiotalar tilt [TT]), foot deformities (lateral talo-first metatarsal angle [Lat talo-1MT], anteroposterior talo-first metatarsal angle [AP talo-1MT], and talonavicular coverage), talar body migration (medial talar center migration [MTCM] and anterior talar center migration [ATCM]), internal rotation (IR) of the talus, and mechanical tibiofemoral angle. All were statistically analyzed using Pearson's correlation coefficients and regression analyses.

RESULTS: Ankle joint orientation to the ground (TPI, p = 0.002), increased foot arch (Lat talo-1MT, p < 0.001), and IR of the talus ( p = 0.001) were significantly associated with ankle joint incongruency (TT) in linear regression analysis. Ankle joint incongruency (TT, p = 0.003), medial talar body migration (MTCM, p = 0.042), and increased foot arch (Lat talo-1MT, p = 0.022) were significantly associated with IR of the talus in the binary logistic regression analysis. MTCM was significantly correlated with TPI ( r = 0.251, p = 0.029), TT ( r = 0.269, p = 0.019), MDTA ( r = 0.359, p = 0.001), ATCM ( r = -0.522, p < 0.001), and AP talo-1MT ( r = 0.296, p = 0.015). ATCM was significantly correlated with TPI ( r = -0.253, p = 0.027), ADTA ( r = 0.349, p = 0.002), and Lat talo-1MT ( r = -0.344, p = 0.002).

CONCLUSIONS: Ankle joint orientation, foot deformities, and talar rotation were associated with ankle joint incongruency in medial ankle osteoarthritis when evaluated radiographically. These findings need to be considered during surgical treatment for medial ankle osteoarthritis. However, the biomechanical significance of these radiographic measurements requires further investigation.