Short-stem anatomical shoulder replacement—a systematic review

Abstract

Background: In shoulder arthroplasty, there is a trend for shorter humeral implants to facilitate stem revision and preserve bone stock. This review evaluates the clinical and radiographic outcome of anatomical total shoulder replacement with uncemented humeral short stems. Methods: A systematic review was performed using PubMed and Cochrane databases. The search terms “short stem” (all) and “shoulder” (title/abstract) were used. The minimum follow-up was 20 months. The demographic data, clinical outcome (pain, range of motion, outcome scores), radiographic outcome (humeral bone adaptations, humeral loosening, glenoid loosening), risk for high radiographic bone adaptations, complications, and revision were determined. Results: Ten studies comprising 653 shoulder arthroplasties were included in the analysis. At an average follow-up of 20–64 months, the clinical parameters of pain, range of motion, and outcome scores improved significantly in all studies. The most frequent radiographic finding was calcar resorption in 15–71% of patients. High filling ratio, lack of metaphyseal porous coating, and poor bone quality were associated with high bone adaptation. The radiographic changes did not influence the clinical outcome in any study. In 13 of 653 patients (2%), humeral stem loosening was observed leading to stem revision in nine patients, with one study reporting eight of 73 patients with humeral stem loosening. The average weighted complication rate was 6% and the average weighted revision rate was 4%. Conclusion: The short- to medium-term results of uncemented anatomical short-stem shoulder arthroplasty are encouraging and the clinical results are comparable to other 3rd- and 4th-generation shoulder arthroplasties. Further studies with longer follow-up are needed to evaluate and understand why the radiographic changes occur and to prove the theory of bone-sparing revision surgeries.