The relationship between postoperative ligament balance and preoperative varus deformity in total knee arthroplasty.

We hypothesize that in knees with severe varus deformities, varus-valgus ligament imbalance tends to remain postoperatively after total knee arthroplasty. The purpose of this study was to evaluate the correlation between preoperative varus deformity and postoperative ligament balance quantitatively measured by stress radiograph using Telos SE in total knee arthroplasty. In this study, 44 knee arthroplasties in 32 patients were evaluated. We defined the angle in varus and valgus stress as "varus angle" and "valgus angle," and the sum of varus angle and valgus angle as "sum of varus-valgus angle." There was a significant correlation between preoperative lateral femoral angle and varus angle (p < 0.0001, r = 0.56), which means that postoperative ligament imbalance tends to remain in knees with preoperative varus deformities. There was a significant correlation between the postoperative period and the sum of varus-valgus angle, which suggests that knees with total knee arthroplasty have potential to increase laxity postoperatively.