Conversion of failed reverse total shoulder arthroplasty to hemiarthroplasty: Three cases of instability and three cases of glenoid loosening

Abstract

Background: Glenoid loosening and postoperative instability are common causes of failed reverse total shoulder arthroplasty (RTSA). When soft-tissue problems or large glenoid bone defect interferes with reimplantation in revision RTSA, conversion to hemiarthroplasty can be considered. We present a case series of patients who underwent conversion to hemiarthroplasty due to glenoid loosening and early instability after RTSAs, along with clinical results. Methods: A total of 72 primary RTSAs using the Aequalis prosthesis were performed at our institution from May 2009 to December 2016. Of these, five patients, including one with humeral neck fracture and absent rotator cuff and four with cuff tear arthropathy, underwent conversion to hemiarthroplasty. Another patient who had RTSA at a local clinic underwent hemiarthroplasty at our institution for unresolved postoperative anterior dislocation. The mean age of the six patients was 71.7 years (range, 62 to 76 years), and the mean follow-up period was 24.4 months (range, 18 to 30 months). Clinical assessments were conducted by using the visual analog scale (VAS), American Shoulder and Elbow Surgery (ASES) score, and University of California at Los Angeles (UCLA) shoulder score at the last follow-up. Results: The conversion to hemiarthroplasty in the six patients dramatically improved the mean VAS score (preoperative, 8.1; postoperative, 2.5), ASES score (preoperative, 22.1; postoperative, 56.5), and UCLA score (preoperative, 12; postoperative, 18.1). However, the range of motion was almost unchanged after surgery. Conclusions: Conversion to hemiarthroplasty can be a good alternative to revision RTSA in patients with serious complications (such as unresolved instability and glenoid loosening) difficult to treat with revision RTSA.