Outcomes of pyrolytic carbon humeral resurfacing hemiarthroplasty compared to best in class total shoulder arthroplasty in young patients with osteoarthritis: analysis from the Australian Orthopaedic Association National Joint Replacement Registry.

Abstract

We compared the survivorship and reasons for revision between pyrocarbon resurfacing and the best performing anatomic total shoulder arthroplasty prostheses from a large national arthroplasty registry. Pyrocarbon hemi-resurfacing and pyrocarbon hemi-arthroplasty is an emerging class of arthroplasty that demonstrates superior survivorship compared to metal hemiarthroplasty and resurfacing. However, it is unknown whether it is a superior option when compared to total shoulder arthroplasty in young patients. The study population included all primary shoulder arthroplasty procedures undertaken for osteoarthritis (OA) in patients aged < 65 years and reported to the Registry between September 2004 and December 2022. The cumulative percentage revision (CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HR) from Cox proportional hazard models adjusted for age and sex. Two cohort groups were compared; pyrolytic carbon (pyrocarbon) humeral hemi-resurfacing (PHR) and five anatomic total shoulder replacement (aTSR) prostheses combinations with the lowest CPR at 5 years, using polyethylene cemented glenoids and restricted to patients aged <65 years. There were 403 PHR with a mean age of 52.5 years and 1,952 aTSR with a mean age of 58.6 years analyzed. There were 20 (5.0%) PHR and 123 (6.3%) aTSR revised with a CPR at 10 years of 7.7% (95% Confidence Interval (CI), 4.7 - 12.4), and 9.0% (95% CI, 7.4 - 11), respectively. The PHR and aTSR revision risk did not differ. The predominant reason for revision was implant breakage (35%) for PHR, compared to loosening (33.9%) for aTSR. Pyrocarbon humeral resurfacing arthroplasty has a comparable survivorship in younger patients compared to best-in-class anatomic total shoulder arthroplasty.