Fashioning Osteochondral Allograft for Humeral Head Defects in Reverse Hill-Sachs Lesions - A Proposed Surgical Technique.

Introduction: Posterior glenohumeral joint dislocations with associated bony lesions are challenging to treat; namely, reverse Hill-Sachs's lesions increase humeral head excursion predisposing to recurrent dislocations. To add to the complexity of management, posterior shoulder dislocations are often missed on plain radiographs, leading to chronicity in presentation. Case Report: We describe here our technique in our case series of three patients. Case I, 32 years, gentleman, presented 3 days after injury. He had a locked posterior dislocation of shoulder which he sustained while he fell asleep and hit a glass table. Shoulder was not reducible in emergency department. Reverse Hill- Sachs's lesion involved 40% of humeral head. Case II, a 54- years- old gentleman, a keen gym trainer . Following sudden withdrawal of diazepam, he woke up lying on the floor and started experiencing shoulder pain. He presented a week following the injury. The dislocated shoulder could not be reduced in emergency department. Bony defect involved 50% of humeral head. Case III, 45 years gentleman who fell off from bike, presented on the same day to the emergency department. The dislocated shoulder was reduced. Defect size was 40% of humeral head.A thorough physical and radiological examination was performed to evaluate the lesion. Delto-pectoral approach was utilized for surgical exposure. Once fully assessed, the lesion is outlined and an oscillating saw is used to create uniform edges - - a regular "orange slice"- shaped defect. The prepared defect size is measured. Calcium phosphate cement is used to fill the defect and form a mould that represents the dimensions of allograft required to recreate the native sphericity of the humeral head. This mould then acts as a reference when fashioning the osteochondral femoral allograft to make sure this fits the defect anatomically. Once the graft is prepared, it is placed into the defect in the correct orientation and fixed in situ using headless screws. We utilized the same technique in all our patients. Conclusion: Reconstruction with osteochondral allograft is a promising technique to help shoulder surgeons achieve good outcomes for these patients. We propose a novel technique for fashioning allograft to anatomically fill the defects from bone loss, aiming to restores the native sphericity of the humeral head.