Total shoulder arthroplasty utilizing mini-stem humeral components: technique and short-term results

Throughout the field of orthopedic surgery, there has been a trend toward using smaller incisions and implants that preserve as much normal anatomy as possible. The use of bone sparing technology, such as partial and full surface replacements of the humeral head, while attractive in younger patients, does not allow the best exposure for proper glenoid replacement. Additionally, there are other situations when the use of surface replacements is contraindicated. There are also patients with an existing total elbow replacement or a humeral malunion or deformity in which a traditional long-stem component would not fit. For these reasons, a mini-stem humeral component for total shoulder arthroplasty was developed. In this study, we hypothesized that total shoulder replacement using the mini-stem humeral component could provide low complication rates and good to excellent results, as measured by postoperative Constant-Murley and UCLA shoulder scores at minimum 2 years postoperatively.

This was a retrospective review of the first 49 mini-stem shoulder replacements (47 patients) for primary osteoarthritis. There were 26 male and 23 female patients. UCLA Shoulder Score and Constant Murley Scores were obtained on all patients at a minimum of 2 years postoperatively (average 29 months; range 24-43 months). Radiographs were interpreted by a musculoskeletal radiologist. Intraoperative blood loss was documented as was postoperative pain using a visual analog pain scale.

Patients experienced over 90% good to excellent results at minimum 2 year follow up. ROM improved significantly in all parameters. Postoperative UCLA scores at final follow up averaged 27.5 while Constant-Murley scores averaged 91. Small lucent lines (<1 mm) were noted in 11 patients. Five of 49 stems were placed in varus but the postoperative result was not affected in any of these patients. One patient suffered an acute subscapularis rupture that required repair.

This is the first report to document the efficacy of mini-stemmed humeral components used during total shoulder arthroplasty. Our study group showed good to excellent results as well as improvement in range of motion at minimum 2-year follow-up. The results presented in this study are comparable to previous outcomes achieved with conventional length humeral components, and suggest that mini-stem humeral components are an effective option for total shoulder arthroplasty.