Femoral component malrotation is a common cause for persisting symptoms and revision following total knee arthroplasty (TKA). There is ongoing debate about the most appropriate use of femoral landmarks to determine rotation. The Sulcus Line (SL, See Figure 1) is a three-dimensional curve produced from multiple points along the trochlear groove. Whiteside's Line, also known as the anteroposterior axis (APA), is derived from single anterior and posterior points. The purposes of the three studies presented are to i) assess the SL in a large clinical series, ii) demonstrate the effect of parallax error on rotational landmarks, and iii) assess the accuracy of a device which transfers a geometrically corrected SL onto the distal cut surface of the femur. The first study assessed the SL using a large, single surgeon series of consecutive patients (n=200) undergoing primary TKA. The postoperative CT scans of patients were examined to determine the final rotational alignment of the femoral component. In the second study measurements were taken in a series of 3DCT reconstructions of osteoarthritic knees (n=44) comparing the rotational landmarks measured along either the mechanical axis or the coronal axis of the trochlear groove. The third study assessed the accuracy of a novel trochlear alignment guide (TAG) using cadavers (n=10)Purpose
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