The Fate of Unresurfaced Patellae in Contemporary Total Knee Arthroplasty: Early to Midterm Results

Zachary J Gunderson; Taylor G Luster; Evan R Deckard; R Michael Meneghini

doi:10.1016/j.arth.2024.01.055

The Fate of Unresurfaced Patellae in Contemporary Total Knee Arthroplasty: Early to Midterm Results

J Arthroplasty. 2024 Feb 7:S0883-5403(24)00082-2. doi: 10.1016/j.arth.2024.01.055. Online ahead of print.

Authors

Zachary J Gunderson¹, Taylor G Luster¹, Evan R Deckard², R Michael Meneghini³

Affiliations

¹ Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana.
² Indiana Joint Replacement Institute, Indianapolis, Indiana.
³ Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, Indiana; Indiana Joint Replacement Institute, Indianapolis, Indiana.

PMID: 38336307
DOI: 10.1016/j.arth.2024.01.055

Abstract

Background: Leaving the patella unresurfaced in total knee arthroplasty (TKA) has increased significantly over the past decade in the United States, likely due to modern patella-friendly implants, complications with resurfacing, and the knowledge that historical studies were scientifically confounded. This study evaluated revision-free survivorship out to 8.5 years in a cohort of contemporary primary TKAs with patella-friendly femoral components and unresurfaced patellae.

Methods: A total of 1,053 consecutive primary TKAs with unresurfaced patellae were retrospectively reviewed. A selective patellar nonresurfacing protocol was used for all cases. Kaplan-Meier survivorship estimates were calculated based on patellar revision and the latest follow-up. An aggressive lateral patellar facetectomy was performed in 78% (823 of 1,053) of cases. The cohort was 62% women and 43% American Society of Anesthesiologists physical status classification I or II with a mean age and body mass index of 65 years (range, 35 to 94) and 35 kg/m² (range, 18 to 65), respectively.

Results: A total of 4 (0.4%, 4 of 1,053) unresurfaced patellae were revised. Three were resurfaced as part of other procedures: 2 for global instability and one for aseptic loosening at a mean of 1.6 years; and one patella was resurfaced by an outside surgeon for unexplained pain. The all-cause revision-free survivorship estimate specifically related to the patella was 98.9% (95% confidence interval, 98 to 100) out to 8.5 years. No significant difference in survivorship was related to patellae with or without a lateral patellar facetectomy (99.5 versus 98.1%, P ≥ .191); however, 3 of 4 patellar revisions occurred in TKAs without a lateral patellar facetectomy (P = .035).

Conclusions: The results of this study demonstrate excellent revision-free survivorship related to unresurfaced patellae, particularly when a lateral facetectomy was performed. These early to midterm results using modern patella-friendly femoral components are promising and comparable to resurfaced patellae in the literature.

Level of evidence: IV.

Keywords: partial lateral facetectomy; patellar resurfacing; patellar retention; secondary resurfacing; survival; unresurfaced patella.