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

Pyrocarbon hemi-resurfacing and pyrocarbon hemi-arthroplasty is an emerging class of arthroplasty that demonstrates superior survivorship compared with metal hemiarthroplasty and resurfacing. However, it is unknown whether it is a superior option when compared to total shoulder arthroplasty in young patients. 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. 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 (HRs) from Cox proportional hazard models adjusted for age and sex. Two cohort groups were compared: pyrolytic carbon (pyrocarbon) humeral hemi-resurfacing (PHR) and 5 anatomic total shoulder replacement (aTSA) prosthesis combinations with the lowest CPR at 5 years, using polyethylene cemented glenoids and restricted to patients aged <65 years. A total of 403 PHRs with a mean age of 52.5 years and 1,952 aTSAs with a mean age of 58.6 years were analyzed. Twenty PHRs (5.0%) and 123 aTSAs (6.3%) were 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 aTSA revision risk did not differ. The predominant reason for revision was implant breakage (35%) for PHR, compared with loosening (33.9%) for aTSA. Pyrocarbon humeral resurfacing arthroplasty has a comparable survivorship in younger patients compared with best-in-class anatomic total shoulder arthroplasty.