INTRODUCTION.
Although the number of total knee replacements (TKR) is rising, the uncertainty of the benefits of patella resurfacing is reflected by the split in operative practices of knee surgeons. Three surgeon cohorts include ‘always, ‘never’ and ‘selective’ resurfacers. We would like to present our findings to facilitate decision making in patella resurfacing.

METHODS.
We retrospectively reviewed joint arthroplasty database in our institution from January 2015-August 2020. All primary TKR were included and divided into two cohorts: TKR with resurfaced patella (RP) and unresurfaced patella (URP). The data was analysed for clinical outcomes, complications, revisions (patella resurfacing as a secondary procedure) and related costs.

RESULTS.
We identified 2700 TKRs (RP cohort–960 and URP–1740). Patients’ average age was 70 years (23-95), 73% females. The average follow-up was 40 months (3-69, median 43). Complication rate and mortality in RP versus URP groups were 1.2% vs 1.9% and 1.1% vs 1.4%, respectively. In URP–10 cases (0.58%) underwent patella-related procedures, while in RP group–0%. Hence, 174 TKRs needed to undergo primary resurfacing (£120/procedure; total £20,880) to avoid one secondary resurfacing procedure (£2,200/procedure). All secondary patella resurfacings were in ‘selective’ group of surgeons. Oxford Knee Score (OKS) improved from pre-operative to 1 year post-TKR from 18 to 42 and 18 to 38 in RP and URP, respectively. The post-operative OKS scores were statistically and clinically superior in RP versus URP cohort (p<0.001 and Minimal Clinically-Important Difference–4). Secondary patella resurfacing led to improvement in OKS, although failed to reach the improvement of primary RP cohort.

CONCLUSIONS.
Patella resurfacing (versus no resurfacing) was found to lead to significant improvement in functional outcomes. However, while avoiding a secondary procedure with its risks, the cost of routine patella resurfacing as a primary procedure was higher than occasional secondary resurfacing. Therefore, each case needs bespoke consideration, as clinical and financial factors need to be balanced.