Fracture of a reverse total shoulder arthroplasty retentive liner

Reverse shoulder arthroplasty may be indicated in shoulders that cannot be effectively managed by conventional reconstruction procedures. Reported complications include instability, infection, hematoma, scapular notching, and premature component loosening. To our knowledge, however, fracture of a humeral component polyethylene inlay has not been described. A 72-year-old man presented with unstable, painful shoulders after undergoing unsuccessful open repairs and acromioplasties at an outside institution for bilateral massive rotator cuff tears. We performed a left reversed shoulder arthroplasty with a 36-mm glenosphere and a +9-mm polyethylene liner. In the operating room under general anesthesia with chemical paralysis and an interscalene block, his shoulder was stable. The patient required revision with a metal 9-mm lateralizer following an atraumatic dislocation 4 weeks postoperatively. Four weeks following the revision, the patient again presented with a dislocated left shoulder without antecedent trauma. During this second revision, the +6-mm standard polyethylene liner was replaced with a +6-mm lateral retentive polyethylene liner. A third revision surgery was performed after the patient experienced 2 more dislocations with minor activity. Intraoperatively, a fracture of the previously placed +6-mm retentive polyethylene liner was noted. This article may represent a case of dramatic scapular impingement by the humeral components. More subtle forms of scapular notching are common and may suggest significant long-term problems. Many reverse shoulder prostheses are being refined or modified in an attempt to eliminate or reduce the scapular notching phenomenon.