Dissociation of the glenoid component in the Macnab/English total shoulder arthroplasty

Three episodes of mechanical glenoid component failure in two patients are presented. The glenoid component that failed is a two-piece polyethylene metal-backed design, with a snap-fip interlock of the polyethylene insert. The mode of failure with this design should caution both orthopaedic surgeons and implant manufacturers that mechanical dissociation of a snap-fit glenoid liner can occur, and that discretion is advised in their design, fabrication, and use.