Does Patellar Resurfacing in Primary Total Knee Arthroplasty Increase the Risk of Manipulation?

Patellar resurfacing in primary total knee arthroplasty (TKA) remains a controversial topic. The purpose of this study is to evaluate whether patellar resurfacing affects early complications and outcomes with a symmetric femoral component design.

Retrospective review was performed from 2015 to 2019 of all primary TKAs performed with the Klassic® Knee System (Total Joint Orthopedics, Inc., Salt Lake City, Utah) yielding a cohort of 526 patients (674 knees). Patients were compared based on whether the patella was resurfaced (391 knees, 58%) or unresurfaced (283 knees, 42%). Pre- and postoperative range of motion (ROM), University of California Los Angeles (UCLA) activity score, and Knee Society clinical (KSC), functional (KSF) and pain (KSP) scores were assessed between groups. Manipulation under anesthesia (MUA) and revisions were evaluated. The resurfaced group was significantly younger and had significantly more female patients, but they had no differences in preoperative body mass index (BMI), knee ROM, or Knee Society scores. One-year minimum follow up was available in 240 patients.

Mean follow up was seven months (range, 1 to 35 months, SD ±7 months). MUAs were performed on 12 knees (4.2%) in the unresurfaced group and 37 knees (9.5%) in the resurfaced group (p=0.01). One patient (0.3%) in the unresurfaced group underwent a revision 1.5 years after the index surgery for a patellar resurfacing and polyethylene exchange. No other revisions were performed in either group. In patients with one-year minimum follow up, there was no significant difference in ROM or clinical or functional outcomes between groups.

Patients who underwent a primary TKA with the TJO Klassic® Knee System with a resurfaced patella had a significantly higher incidence of manipulation under anesthesia than those with an unresurfaced patella. At most recent follow up, there was no significant difference in mean ROM or clinical outcome scores.