Effect of Lower-Extremity Angular Imbalance on Foot and Ankle Pain in Patients With Genu Varus Deformity.

When there is a varus knee deformity, the ankle and foot compensate. However, the association between pain and angular change in the compensatory mechanism is not well understood. Therefore, we investigated the relationship between pain and angular change of the lower extremity in genu varus patients. Standing whole-lower-leg plain radiographs of 127 legs (77 patients) with >4° of genu varum were evaluated. Pain was assessed separately at the ankle, forefoot, and hindfoot. Knee, ankle, and subtalar joint angles were measured. Patients were divided into 3 groups according to the degree of lower leg angular imbalance (group 1, mild; group 2, moderate; group 3, severe). The presence of multiple pain locations differed significantly between groups and was significantly higher in group 3 than group 1 (p = .0061). Likewise, the subtalar angle was significantly more varus in group 3 than group 1 (p = .012). In conclusion, an unbalanced lower extremity with genu varum was associated with multiple foot and ankle pain, and the subtalar joint played a primary role in compensation for genu varum deformity.