Evaluation of knee and hindfoot alignment before and after total knee arthroplasty: a prospective analysis

A prospective study on 100 cases was performed to evaluate the effect of total knee arthroplasty (TKA) on hindfoot alignment, and to compare knee alignment and hindfoot alignment preoperatively and postoperatively. Preoperative knee alignment ranged from 30 degrees of valgus to 13 degrees of varus. Postoperative knee alignment ranged from 14 degrees of valgus to 0 degrees. Preoperative foot alignment ranged from 22 degrees of valgus to 13 degrees of varus. Postoperative foot alignment ranged from 22 degrees of valgus to 11 degrees of varus. Preoperative knee alignment did not correlate with foot alignment (P =.182). Postoperative knee alignment and foot alignment also showed no correlation (P =.222). Preoperative and postoperative knee alignment were correlated, as expected (P =.000). Notably, hindfoot alignment was changed by knee arthroplasty, and changed in a predictable fashion (P=.000). The alignment of the foot before knee arthroplasty was the largest contributing factor to the hindfoot alignment after arthroplasty of the knee. Hindfoot alignment was changed by TKA, and changed in a predictable fashion.