Hindfoot alignment variation before and after totalknee arthroplasty results of a pilot study.

Limb alignment to balance the weight transmission across the knee joint is essential part of total knee replacement surgery. Conventionally the hipkneeankle (HKA) axis is considered for correction; however the weight transmission to the ground also involves the joints distal to ankle. Heel alignment will thus play and important part in weight transmission. Genu varum deformities in osteoarthrosis are associated with heel valgus deformity and we hypothesize that this deformity persists even after correction of the knee deformity after TKR.

patients with primary knee osteoarthrosis genus varus deformity >10° but <30° were included in the study. Preoperative and three months post operative scanogram and cosby's ankle radiographs are taken. The HKA and the tibi calcaneal angles were measured and compared using paired t test. Preoperative genu varum was also correlated with preoperative tibio calcaneal angle using Pearson's correlation

the mean HKA improved from a preoperative value of 16.53° (valgus) to 1.36° (valgus). The tibia calcaneal angle slightly increased postoperative from 13.16° (valgus) to 14thus the knee alignment returned to normal HKA, however the heel valgus did not change at three months post surgery. This will further lateralize the weight transmission axis.

This is a small sample, short follow up pilot study; however it does indicate that the heel valgus deformities may persist after total knee replacement. This may be needed to be considered while preoperative planning, however a longer follow up will be required to assess the complication rates and clinical result.