Anatomic and Reverse Stemless Shoulder Arthroplasty: Functional and Radiological Evaluation

BACKGROUND: Stemless shoulder arthroplasty was developed to restore the glenohumeral centre of rotation without violation of the humeral shaft. It allows the preservation of humeral bone stock. Complications related to stem malalignment and periprosthetic fractures can be avoided. PATIENT AND METHODS: This is a prospective observational study that reports outcomes of 46 patients who received stemless shoulder arthroplasty “Comprehensive Nano implant ®.” The series includes Group (A): 30 anatomic and one hemiarthroplasty. Group (B): 15 reverse stemless replacement. Functional outcomes were assessed by visual analog score (VAS), satisfaction, range motion, Constant score, and American Shoulder and Elbow Score (ASES). RESULTS: The mean follow-up was 40.4 ± 12 months (range, 24 months to 60 months). Group (A): VAS and satisfaction improved by 5.3 and 67.5 points respectively. Constant score significantly improved from 28.5 ± 14.5 to 62.5 ± 23 P = <0.001. The radiological assessment showed the mean centre of rotation (COR) deviation was 2.8 ± 1.9 mm. 27% of patients have COR discrepancy of more than 4 mm. In Group (B), patients reported a significant improvement in VAS, Satisfaction, and ASES P = 0.002, 0.002, and 0.003, respectively. Complications include shoulder pain with progressive loss of movements, aseptic loosening early subscapularis rupture, glenohumeral dislocations, and humeral component migration. CONCLUSION: Anatomic Stemless total shoulder arthroplasty offers acceptable results and improvement of overall functional outcomes.