The Impact of Patellar Resurfacing on Costs and Outcomes in Primary Total Knee Arthroplasty

Introduction: Patellar resurfacing in primary total knee arthroplasty (TKA) has been debated for decades. This study aimed to evaluate cost-effectiveness and clinical outcomes of patellar resurfacing in modern TKA at a high-volume arthroplasty center. Methods: A retrospective study was conducted on 4,534 patients who underwent unilateral, elective, primary TKA from 2021 to 2024 at an urban academic institute. Patients were stratified by patellar resurfacing: resurfaced (n=3,753) or not (n=781). Baseline characteristics, operative costs [implants, anesthesia, operating room time], and postoperative outcomes (revision incidence) were collected. The median follow up was 2.0 years (1.0- 4.8). The individual cost of patellar component was adjusted for implant manufacturer and cementation out of total implant cost. Multivariable regression analysis determined added operating room time (ORT) due to patellar resurfacing, controlling for body-mass index, usage of robotics, navigation and cementation. Relative costs of added ORT and the patellar component were compared to total implant and procedure costs of patellar-resurfacing operations. Results: The patellar component accounted for an average of 7.9% of the total implant cost in patellar-resurfacing operations. Patellar-resurfacing operations had longer operative times (112.2 vs. 105.4 minutes, P<0.001), and multivariable regression determined patellar resurfacing is associated with an added 6.3 minutes of total ORT (P<0.001). The patellar component implant cost and the cost of added ORT due to resurfacing accounted for 4.5% of the total procedure cost in resurfaced group. Resurfaced group had an overall 5% higher total operative cost than the non-resurfaced group. No differences existed in length of stay (LOS), discharge disposition, or all-cause and patella-specific revision incidence. Conclusion: We found that patellar resurfacing was associated with longer operative times and greater implant and procedure costs, although there was no effect on LOS, discharge disposition, or all-cause and patella-specific revision incidence. Ultimately, the decision to resurface the patella in primary TKA should be based on patient-specific indications and clinical judgment. However, it is important to consider the additional cost associated with this procedure.