Changes in the Medial and Lateral Posterior Condylar Offset in Total Knee Arthroplasty

The purpose of this study was to clarify the changes between preoperation and postoperation in each posterior condylar offset (PCO) using computed tomography (CT) and to compare them to conventional radiographic (x-ray) evaluation in total knee arthroplasty. One hundred nine knees in 97 patients were evaluated. The medial PCO was significantly larger before surgery. The lateral PCO was significantly larger after surgery. Changes in the PCO on x-ray showed no significant correlation with the changes observed in the CT-evaluated medial (R = 0.028) and lateral PCO (R = 0.190). Changes in PCO observed by x-ray did not reflect those of the medial or lateral condyles on CT. We recommend CT-based evaluation of PCO by condyle when assessing the influence of PCO on range of motion following total knee arthroplasty.