Are there differences between stemless and conventional stemmed shoulder prostheses in the treatment of glenohumeral osteoarthritis?

Background: Conventional stemmed anatomical shoulder prostheses are widely used in the treatment of glenohumeral osteoarthritis. The stemless shoulder prosthesis, in contrast, is a new concept, and fewer outcome studies are available. Therefore, the purpose of the study was to investigate the early functional outcome and postoperative proprioception of a stemless prosthesis in comparison with a standard stemmed anatomic shoulder prosthesis. Methods: Twelve patients (mean age 68.3 years [SD +/- 5.4]; 5 female, 7 male) with primary glenohumeral osteoarthritis of the shoulder were enrolled, who underwent total shoulder arthroplasty (TSA) with a stemless total shoulder prosthesis, Total Evolution Shoulder System (TESS (R); Biomed, France). The control group consisted of twelve (age and gender matched) patients (mean age 67.8 years; [SD +/- 7.1]; 9 female, 3 male), getting a TSA with a standard anatomic stemmed prosthesis, Aequalis (R) Shoulder (Tournier, Lyon, France). Patients were examined the day before and six months after surgery. The pre- and postoperative Constant Score (CS) was evaluated and proprioception was measured in a 3D video motion analysis study using an active angle-reproduction (AAR) test. Results: Comparing the postoperative CS, there was no significant difference between the groups treated with the TESS (R) prosthesis (48.0 +/- 13.8 points) and the Aequalis (R) prosthesis (49.3 +/- 8.6 points; p = 0.792). There was no significant difference in postoperative proprioception between the TESS (R) group (7.2 degrees [SD +/- 2.8]) and the Aequalis (R) group(8.7 degrees [SD +/- 2.7]; p = 0.196), either. Comparison of in the results of CS and AAR test pre-and postoperatively showed no significant differences between the groups. Discussion: In patients with glenohumeral osteoarthritis, treated with TSA, the functional and the proprioceptive outcome is comparable between a stemless and a standard stemmed anatomic shoulder prosthesis at early followup. Conclusion: Further follow-up is necessary regarding the long-term performance of this prosthesis.