The aim of this retrospective research is to evaluate the changes in ankle alignment due to knee malalignment and relation with valgus knee osteoarthritis, further study the knee-ankle alignment after total knee arthroplasty(TKA).

This research consisted of 44 patients who had underwent primary TKA due to vaglus knee osteoarthroplasty(OA). The alignment and angles in the selected knees and ankles were measured on full-length standing anteroposterior radiographs, both pre-operatively and post-operatively. The knee alignment was estimated according to the hip-knee-ankle angle(HKA), Tibiofemoral angle(TFA), Femoral valgus angle(FVA), Femoral angle(FA), Tibial angle(TA) and Tilt angle of the knee (TAK). The ankel alignment was estimated according to Distal tibial articlar angle(DTAA), Talar tilt angle(TTA) and Tilt angle of ankle(TAA). The patients were separated into two sex-based group. The correlation between the knee and ankle parameters were estimated by the two-tailed paried t-test and Pearson's correlation tests.

The results showed that valgus knee deformity accompany with the compensatory varus ankle deformity. After TKA, with correclation of knee alignment, the parameters of knee were significantly improved, and the parameters of ankle were uniformly improved. There was correlation between changes of ankle alignment and that of knee alignment(P<0.01).

The primary TKA could correct the vaglus deformity of a knee, and improve the tilt of the ankle. Ankle alignment correlated with knee alignment both pre-operatively and post-operativly. Both knee and ankle malalignment can be stimulateously corrected following TKA.