Postoperative femoral component rotation and femoral anteversion after total knee arthroplasty in patients with distal femoral deformity.

Abstract

We asked whether total knee arthroplasty (TKA) in patients with distal femoral deformity (DFD) would change femoral component rotation (FCR) and investigated the correlation between DFD and femoral anteversion (FA). 75 patients were divided into two groups according to the preoperative posterior condylar angle (PCA); group A without DFD (PCA<7°), group B with DFD (PCA>7°). We evaluated the different angles on the CT scan: (1) PCA, (2) angle between the line which is perpendicular to the Whiteside's line and PCL (WLP), and (3) FA. The mean FCRs were external rotation of 0.21°+2.75° in group A and internal rotation of 4.48°+2.51° in group B (P=0.001). The mean preoperative and postoperative FAs were similar in group A but were significantly different in group B (P=0.035). DFD resulted in excessive internal rotation of the femoral component. There was a secondary decrease in FA in patients with DFD.