Middernacht, Bart × De Wilde, Lieven Molé, Daniel Favard, Luc Debeer, Philippe #
Clinical Orthopaedics and Related Research vol:466 issue:4 pages:892-898
Implant failure is a serious complication in reverse shoulder arthroplasty. We determined the incidence of glenosphere disengagement in a cohort of 479 reverse shoulder prostheses (468 Delta IIItrade mark [DePuy International Ltd, Leeds, UK], 11 Aequalistrade mark [Tornier, Grenoble, France]). We also determined whether disengagement adversely affected clinical outcomes. The minimum followup was 12 months (mean, 28.6 months; range, 12-72 months). Disengagement of the glenosphere occurred in 16 of 479 shoulders (3.2%). In 13 patients, the disengagement was partial (clear step-off between the baseplate and the glenosphere) and was not associated with a poor functional outcome with this short-term followup. In three patients, the disengagement led to a fracture of the central screw, leading to a complete disengagement of the glenosphere from the baseplate, necessitating revision in two; the third refused revision. Partial disengagement was seen in five of 11 Aequalistrade mark prostheses (45.4%) and eight of 468 Delta IIItrade mark prostheses (1.7%). The three total disengagements with central screw breakage all occurred in Delta IIItrade mark prostheses. We believe differences in the type of locking screws may explain the differences observed between the two types of reverse prostheses. Level of Evidence: Level III, retrospective study. See the Guidelines for Authors for a complete description of levels of evidence.