Leaving the Patella Unresurfaced Does Not Increase the Risk of Short-Term Revision Following Total Knee Arthroplasty: An Analysis from the American Joint Replacement Registry (AJRR)

The benefit of patellar resurfacing in total knee arthroplasty (TKA) remains uncertain, with conflicting evidence regarding associated revision rates and clinical outcomes. Although initial studies have reported higher revision rates associated with unresurfaced patellae, recent evidence questions the necessity of routine patellar resurfacing. This study aimed to evaluate the risk of revision following TKA performed with and without patellar resurfacing using data from the American Joint Replacement Registry (AJRR).

The AJRR was queried for all patients aged 65 years and older undergoing elective TKA between January 2012 and March 2020 with a minimum 2-year follow-up. Cases were linked using supplemental Centers for Medicare and Medicaid data. Cases with hybrid fixation, highly constrained implants, and revision components were excluded. Patients were categorized into two groups: those with a resurfaced patella and those without. Cumulative incidence function (CIF) curves and cause-specific Cox models were utilized to assess all-cause revision risk, adjusting for sex, age, femoral design (cruciate retaining vs. posterior stabilized), fixation type (cemented vs. cementless), and Charlson Comorbidity Index.

Of the 390,304 TKAs with minimum 2-year follow-up in our cohort, 22,829 had no patellar resurfacing performed. Adjusted hazard ratios (HRs) revealed no significant difference in all-cause revision (HR = 0.96, 95% confidence interval [CI]: 0.81–1.13, p = 0.656), revision for mechanical loosening (HR = 1.61 [0.88, 2.93], p = 0.122), or revision for infection (HR = 1.02 [0.79, 1.33], p = 0.860) associated with patellar resurfacing status.

Our study found that patients with an unresurfaced patella do not face an increased short-term revision risk following TKA. These findings challenge the necessity of routine patellar resurfacing and underscore the importance of considering other factors, such as femoral design, patient comorbidities, and implant-related variables in revision risk stratification.