Patients undergoing total knee arthroplasty using a contemporary patella-friendly implant are unaware of any differences due to patellar resurfacing

Abstract

Purpose: Anterior knee pain after total knee arthroplasty (TKA) is often unexplained, spurring ongoing debates on the need for patellar resurfacing. It was hypothesized that a contemporary patella-friendly implant would restore patellofemoral kinematics more physiologically than outdated implants and that there would be no perceived or clinically demonstrable differences due to resurfacing of patella (RP).

Methods: This prospective bilateral randomized study was undertaken in 49 patients scheduled for the same-day bilateral TKAs. One knee was subjected at random to RP while withholding RP on the opposing side (non-RP). A recently approved single-radius femoral prosthesis featuring a deep, elongate trochlear groove with lateral tilt and a high lateral flange was implanted bilaterally in all patients. Mean follow-up duration was 5 years. Group comparisons were based on patient-reported outcomes [anterior knee pain, Forgotten Joint Score (FJS), and side preference], physician-rated results [Feller patellofemoral (PF) score], radiographic patellar position, patella-related complications, and need for reoperation.

Results: There were no differences in midterm rates of anterior knee pain (RP 8%; non-RP 4%; n.s.), FJS (all n.s.), or side preference (RP 47%; non-RP 45%; n.s.), nor did the groups differ by Feller PF score (all n.s.) or radiographic patellar position (all n.s.). No secondary resurfacings of non-RP or RP revisions were required.

Conclusions: Patients were incapable of distinguishing whether RP was done, casting doubt on its benefits. Surgeons may thus forego RP during TKA when using contemporary patella-friendly TKA implants.

Level of evidence: Therapeutic study, Level I.

Keywords: Osteoarthritis; Patella; Patella-friendly design; Patellar resurfacing; Total knee replacement.