Long-term humeral complications after Grammont-style reverse shoulder arthroplasty

Abstract

Background: Recent experiences with Grammont reverse shoulder arthroplasty (RSA) have revealed some problems related to the biomechanical changes of the shoulder and humeral stem complications. We analyzed humeral complications in a long-term follow-up of a large series of RSAs, searching for correlations between these and the initial etiology, the follow-up duration, and the clinical outcomes.

Materials and methods: Preoperative and postoperative clinical and radiologic assessments of 1035 RSAs with a minimum 5-year follow-up (implanted in 7 specialized shoulder centers between 1993 and 2010) were retrospectively collected. Postoperative humeral complications, managed conservatively or surgically, were radiographically documented.

Results: Overall, a 3.3% rate of postoperative humeral complications was found in our database. We identified 17 cases (1.6%) with postoperative humeral fractures, 15 cases (1.4%) with aseptic humeral loosening, and 3 cases (0.3%) with humeral stem disassembly. The humeral complications were more frequent in RSAs implanted for tumors, fracture sequelae, and revision for failed arthroplasty.

Discussion: Humeral complications after RSA are not rare, increase with longer follow-up, and have a negative impact on functional outcomes. Postoperative humeral fractures are more frequent in elderly patients, operated on through a superior approach, and after cemented stem implantation. In the absence of associated humeral loosening, conservative treatment should be preferred. Proximal humeral bone loss (due to revisions and tumors) is the most significant risk factor for humeral loosening. Implant unscrewing was initially related to a technological problem, which has been solved, and this complication has disappeared.

Keywords: Reverse shoulder arthroplasty; clinical outcomes; complications; disassembly; fracture; humeral stem; loosening; subsidence.