Three Dimensional CT-based Virtual Patellar Resection in Female Patients Undergoing Total Knee Replacement: A Comparison between Tendon and Subchondral Method

Background

Due to its small size, variable shape, and lack of distinct anatomical landmarks, osteoarthritic knees make a precise patellar resection extremely difficult.

Methods

We performed virtual patellar resection with digital software using three dimensional computed tomography scans of knees from 49 patients who underwent primary total knee replacement at our hospital. We compared 2 commonly used resection methods, the tendon method (TM) and the subchondral method, 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 superior-inferiorly, as well as mediolaterally.

Conclusions

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