Three Dimensional CT based Virtual Patellar Resection in Female Patients undergoing Total Knee Replacement

Abstract

Background: Though rotational alignment and antero-posterior positioning of the femoral component influences patello-femoral mechanics, it is also significantly influenced by the accuracy of the patellar resection, with the resultant thickness and symmetry of the patella-implant composite

Methods: We performed virtual patellar resection with digital software using 3D-CT scans of knees from 49 patients who underwent primary TKR at our hospital, comparing two commonly used resection methods, i.e., the tendon method (TM), and the subchondral method (SCM), to determine an ideal resection plane with respect to the symmetry and thickness of the patellar remnant.

Results: The TM gave a thicker resected patella, and a less oval cut surface shape which gives better coverage for a domed prosthesis. Both methods however, gave a symmetric resection both superio-inferiorly as well as medio-laterally.

Conclusions: Though TM appears statistically better with respect to the thickness and cut surface shape, only further intra-operative studies with long-term clinical follow up may provide us with the most appropriate patellar resection method.