Similar secondary patellar resurfacing but higher tibial revision risk with posterior stabilized versus medial pivot total knee arthroplasty: A registry analysis.

Abstract

Patellar complications are among the most frequent causes of revision after primary total knee arthroplasty (TKA). The primary study objective is to compare the rate of secondary patellar resurfacing between medial pivot (MP) and posterior stabilized (PS) designs in TKAs. Analysis of the Swiss national knee joint registry, including TKAs without patellar resurfacing at index surgery performed between 2012 and 2023. Only TKAs with MP and PS designs featuring cemented femoral and tibial components were included. Time-to-event analysis was performed using Kaplan-Meier curves and Cox proportional hazards regression. Multivariable models adjusted for age, sex and BMI. A total of 32,540 TKAs were included in the final analysis. Component revision was performed in 5.8% (<i>n</i> = 1873) of cases. The revision rate was 5.2% (<i>n</i> = 916) for MP and 6.4% (<i>n</i> = 957) for PS designs (<i>p</i> = 0.7). Secondary patellar resurfacing was the most common revision procedure, accounting for 41.8% (<i>n</i> = 383) of MP revisions and 37.7% (<i>n</i> = 361) of PS revisions. No significant difference was observed between designs for secondary patellar resurfacing (adjusted hazard ratio [HR] = 0.93; 95% confidence interval [CI] = 0.79-1.11; <i>p</i> = 0.43). PS designs showed significantly higher risk for tibial revision (unadjusted HR = 1.55; 95% CI = 1.07-2.25; <i>p</i> = 0.02, adjusted HR = 1.51; 95% CI = 0.98-2.31; <i>p</i> = 0.06). Younger age and female sex were independent risk factors for both revision types. No difference in secondary patellar resurfacing rates was observed between MP and PS designs in primary TKA. However, PS designs are associated with increased tibial revision risk compared to MP designs. Level III.