Strategies for the planning of complex shoulder arthroplasty: Use of a custom-made glenoid component in reverse shoulder arthroplasty for a neglected posterior fracture dislocation of the shoulder with malunited scapula fractures and severe eccentric glenoid bone loss.

Glenoid bone loss associated with abnormal glenoid morphology can be encountered in complex primary and revision reverse shoulder arthroplasty. Strategies to deal with this include allografts, augments and custom-made prostheses. We describe a unique case of a long-standing neglected posterior fracture dislocation of the shoulder with severe glenoid bone loss and retroversion. The patient also had malunited acromial and scapula fractures and an associated rotator cuff tear. The primary challenges were access to the shoulder joint due to the malunited fractures, reconstruction of the dysplastic glenoid and providing joint stability. A reverse shoulder replacement was planned using a custom-made glenoid component and patient-specific instrumentation (PSI). The custom base plate was manufactured based on the pre-operative computerised tomography (CT) scan and conformed to the native glenoid. A post-operative CT scan confirmed adequate positioning of the implants. 30 months following surgery, there was a significant improvement in pain and range of motion with an Oxford Shoulder Score (OSS) of 39/48, compared to a pre-operative score of 12/48. Plain radiographs did not show any evidence of loosening or osteolysis. This case report highlights the approach for planning a complex reverse shoulder arthroplasty and the use of custom-made prostheses and PSI in such scenarios.