Large thigh girth is a relative contraindication for the subvastus approach in primary total knee arthroplasty

The purpose of this study was to determine the thigh girth cutoff limit for the subvastus approach in primary total knee arthroplasty. One hundred forty-three consecutive total knee arthroplasties were done using the subvastus approach by one surgeon. The larger the thigh girth, the higher the risk for inability to evert the patella. We found that patients with a thigh girth greater than 55 cm had 27.212 times higher risk for inability to evert the patella during the subvastus approach as compared with patients with a small thigh girth (ie, <45 cm; odds ratio = 27.212; 95% confidence interval = 4.394-168.530). If we could not evert the patella in patients with a large thigh girth, although we could slide the patella, the extensor mechanism and excessive soft tissues were obstacles to the procedure. We recommend that another approach for patients with a thigh girth greater than 55 cm be used.