Skin incision translation in total knee arthroplasty: the difference between flexion and extension

Scar location and point loading of the scar after total knee arthroplasty are common postoperative concerns for patients and physicians. A frequent problem is discomfort associated with the incision. We evaluated 40 knees to better understand the association of the tibial tubercle with the overlying skin in both flexion and extension. Our results revealed lateral translation of the skin overlying the tibial tubercle in 100% of our volunteers as the knee is flexed and the tibia internally rotates. The average amount of lateral translation measured 9.7 mm. This could have a significant impact on point loading of the scar if an anterior midline incision for total knee arthroplasty is planned in extension.