Stemless humeral head hemiarthroplasty for multiple indications in younger patients aged ≤ 65 years

Aims: Stemless humeral head arthroplasty (HHA) offers a treatment option for various irreversible shoulder pathologies. This study aimed to report long-term results of HHA as a hemiarthroplasty for different indications in patients aged ≤ 65 years. Methods: Patients documented in a prospectively collected local database who underwent stemless HHA with a minimum follow-up of 12 years and a maximum age at surgery of 65 years were included. In all, 88 shoulders (86 patients) were available for cumulative revision-free implant survival analysis according to the Kaplan-Meier method. The clinical evaluation included the Constant-Murley Score (CMS) and the range of movement (ROM). Radiologically, glenoid erosion and offset reconstruction parameters were assessed. Results: Kaplan-Meier analysis with a cumulative revision-free implant survival was 77.7% (95% CI 66.4 to 85.6; number at risk: 34) at 15 years. Glenoid erosion (n = 13; 14.8%) and rotator cuff defects (n = 5; 5.7%) were the causes of revision. Patients with humeral pathologies (humeral head necrosis, fracture sequelae) had a significantly higher survival rate compared to patients with glenohumeral pathologies (primary or secondary osteoarthritis) (90.8% vs 66.7% at 16.6 years; p = 0.016). In total, 25 shoulders (13 (52%) female; mean age 50 years) underwent long-term follow-up evaluation at a mean 16.6 years (12.3 to 22.0). Age- and sex-adjusted CMS showed clinically relevant improvement from preoperative (36.7%) to long-term follow-up (72.5%) (p < 0.001). ROM improved for flexion (p = 0.002), abduction (p = 0.005), and for external rotation, but without statistical significance (p = 0.051). Radiologically, the offset parameters did not change significantly after surgery; nine (43%) patients exhibited moderate-to-severe glenoid erosion at the long-term follow-up. Conclusion: Stemless HHA provides acceptable-to-good clinical long-term results with high patient satisfaction in younger patients. Humeral-sided pathologies show promising revision-free implant survival, while implant survival rates for glenohumeral conditions were lower.