gms | German Medical Science

Objectives: Short stem and stemless prostheses are becoming increasingly popular, due to technologic innovation and greater emphasis on bone preservation. These implants provide metaphyseal fixation with minimal bone resection, preserving the patient’s bone stock. Potential benefits include a lower risk of periprosthetic fracture, reduced stress shielding, lower infection rate due to faster implantation, and the potential for easier revision surgery if needed. Despite these innovations clinical data is scarce – a mere ~ 1% utilization of stemless implantsin primary RSAs (reverse shoulder arthroplasty) is reported in national arthroplasty registries. The purpose of this study was to show mid to long-term results of stemless RSA.

Methods: The study involved a cohort with cuff-tear arthropathy treated with a stemless RSA between July 2009 and July 2013 by a single surgeon. Follow-up examinations were conducted in 2014 and 2020 by two independent observers. Data collected included patient demographics, clinical scores, pain levels, satisfaction, radiographic evaluations, and post-operative complications. Statistical analysis was performed using descriptive statistics and Wilcoxon signed rank tests. The level of significance was set at P < 0.05.

Results and conclusion: Within a geriatric cohort of 37 patients, 19 patients aged 82 ± 6 were included with a mean follow up of 102 months. 74% of surgeries involved a stemless RSA on the right side, with a mean operating time of 84 ± 22 minutes. Comparison of clinical scores between 2014 and 2020 did not reveal significant differences in ASES – American Shoulder and Elbow Surgeon-Scores (86.7; 90.3) or Constant-Scores (75;76). Radiologic lucencies around the humeral component were observed in 4 patients with no clinical signs of loosening. Four complications (21%) were noted including 2 acromial stress fractures with one undergoing secondary ORIF, and 2 postoperative joint contractions, with both complications leading to significantly worse constant scores (P < 0.01) at both follow ups. No infections and no cases of revision were documented.

Ours is one of the very few studies presenting a long-term follow-up of 102 months. Constancy of scores in between medium and long-term follow-up indicate a sustained biomechanical reconstruction. Opposed to literature, we observed radiolucencies around the humeral component, their clinical significance seems negligible. Our findings suggest that stemless RSAs offer promising long-term results. Published results of stemmed designs are comparable. To underline potential benefits of stemless RSAs, such as lower infection rates and favorable outcomes in case of revisions, further investigation is required. Limitations include potential bias in radiological assessment and a modest sample size.