Background and purpose: Whether or not to resurface the patella during primary total knee arthroplasty (TKA) remains controversial. We aimed to investigate the association between patellar resurfacing and patient-reported outcome measure (PROM) improvement 1 year postoperatively in terms of physical functioning and pain following TKA. Patients and methods: We performed an observational study using the Dutch Arthroplasty Register on prospectively collected PROM data (n = 17,224, years 2014–2019). Preoperative and 1-year PROM pain scores (NRS at rest; during activity) and physical functioning scores (KOOS-PS, OKS) were examined. Stratification was performed for cruciate-retaining (CR) and posterior-stabilized (PS) and for the 4 most frequently used TKA implants in the Netherlands (Nexgen, Genesis II, PFC/Sigma, Vanguard) using multivariable linear regression adjusting for age, ASA classification, preoperative general health (EQ VAS), and preoperative PROMs. Results: 4,525 resurfaced and 12,699 unresurfaced patellae in TKA were analyzed. Overall, no significant difference in 1-year PROM improvement was found between the 2 groups. In CR TKAs, resurfacing resulted in less improvement in KOOS-PS and OKS (adjusted difference between groups (B) –1.68, 95% confidence interval (CI) –2.86 to –0.50 and B –0.94, CI –1.57 to –0.31. Fewer improvements for patellar resurfacing in TKA were found for the Genesis TKA on NRS pain at rest (B –0.23, CI–0.40 to –0.06) and Oxford knee score (B –1.61, CI –2.24 to –0.98). Conclusion: No significant differences were found in 1-year improvement of physical functioning and pain between TKA with resurfaced and unresurfaced patellae.