Use of reverse stemless shoulder arthroplasty in a patient with multiple hereditary exostosis

Introduction: Multiple hereditary exostosis (MHE) is the formation of benign, cartilage-capped bony outgrowths predominantly extending from the metaphysis of long bones that presents with reduction in growth, deformity, restricted motion, short stature and premature osteoarthritis.

Aim: To review the clinical and radiological results of a stemless reverse shoulder arthroplasty in a case of MHE.

Case: 81-year-old, right hand dominant short-statured retired male engineer with long standing shoulder pain and restricted movements on the background of an old proximal humeral fracture managed conservatively.The radiographs revealed osteoarthritis and a mal-united proximal humerus fracture on the background of MHE with 3 plane bone deformity and a lack of medullary canal.

Results: The patient underwent a stemless reverse shoulder arthroplasty. At 6 months post operatively the patient had recovered well with a range of movement including: forward flexion 110°, external rotation 20° and abduction of 80°. Internal rotation remained limited to buttocks. Improved ADLIER, Subjective shoulder value and Constant Murley score compared to pre-operative figures.

Conclusion: The stemless humeral component relies on metaphyseal impaction for stability. When the humeral canal is malformed or in presence of malunited distal fractures, it circumvents the need of navigating a deformed diaphysis with encouraging postoperative results.