Patellar resurfacing as a prognostic variable in total knee arthroplasty: a two‑decade retrospective cohort (2000‑2020).

BACKGROUND: The impact of patellar resurfacing (PR) on long-term outcomes following primary total knee arthroplasty (TKA) remains a topic of debate. METHODS: This study examined a retrospective cohort of 334 primary total knee arthroplasties (TKAs) performed between 2000 and 2020 at a specialized hospital. The surgeries were conducted from January 2000 to December 2020, allowing for a maximum potential follow-up period of 20 years. The primary endpoint assessed was the rate of any-cause revision. Secondary endpoints included anterior knee pain, aseptic loosening, patient-reported outcomes (Western Ontario and McMaster Universities Osteoarthritis index and Oxford Knee Score), and complications. Kaplan-Meier estimates and multivariable Cox models, adjusted for age, body mass index, and inflammatory arthropathy, were utilized. RESULTS: PR yielded an absolute risk reduction (ARR) of 83% for anterior knee pain (2.2% in the PR group vs. 85.2% in the WPR group; number needed to treat ≈ 1–2) and an ARR of 7.5% for aseptic loosening (4.4% vs. 11.9%; NNT = 14). The overall revision rates were 5.1% for PR and 6.7% for WPR, demonstrating no significant differences (hazard ratio 0.65, 95% confidence interval 0.30–1.42). CONCLUSIONS: Patellar resurfacing significantly alleviates anterior knee pain and decreases the risk of aseptic loosening without raising the overall revision rate. These findings advocate for a selective resurfacing approach targeting patellae at a higher risk of pain rather than adopting a routine or universal resurfacing strategy. TRIAL REGISTRATION: Not applicable, this study is an observational retrospective cohort; no prospective registration was required.