This cadaveric biomechanical study tests whether a posterior acromial bone graft (the Scapinelli technique) restores posterior shoulder stability when the acromion is high and flat. Eight shoulders with normal glenoid anatomy were tested across moderate malalignment, severe malalignment, each augmented with a graft, and corrective osteotomy. Force, displacement, and acromiohumeral contact pressure were measured in load-and-shift and jerk test positions.
When a patient has posterior instability driven by a high, flat acromion rather than glenoid retroversion or bone loss, this study says you can address the acromion directly. The posterior acromial bone graft extends the acromion's natural buttress, and in this model it matched or beat corrective osteotomy while being technically simpler.
That matters because conventional approaches fail often: up to 35% for capsulolabral repair, up to 73% for open posterior bone block, up to 33% for glenoid osteotomy. Acromial morphology is a structural driver those procedures never address.
Know the caveat: in a dysplastic acromion whose posterolateral corner sits medial to the humeral head, the graft cannot buttress effectively and osteotomy may still be needed. This is cadaveric, single-graft-size, normal-glenoid data with n=8. It validates the biomechanical concept but does not yet establish clinical indications.
This cadaveric biomechanical study tests whether a posterior acromial bone graft (the Scapinelli technique) restores posterior shoulder stability when the acromion is high and flat. Eight shoulders with normal glenoid anatomy were tested across moderate malalignment, severe malalignment, each augmented with a graft, and corrective osteotomy. Force, displacement, and acromiohumeral contact pressure were measured in load-and-shift and jerk test positions.
When a patient has posterior instability driven by a high, flat acromion rather than glenoid retroversion or bone loss, this study says you can address the acromion directly. The posterior acromial bone graft extends the acromion's natural buttress, and in this model it matched or beat corrective osteotomy while being technically simpler.
That matters because conventional approaches fail often: up to 35% for capsulolabral repair, up to 73% for open posterior bone block, up to 33% for glenoid osteotomy. Acromial morphology is a structural driver those procedures never address.
Know the caveat: in a dysplastic acromion whose posterolateral corner sits medial to the humeral head, the graft cannot buttress effectively and osteotomy may still be needed. This is cadaveric, single-graft-size, normal-glenoid data with n=8. It validates the biomechanical concept but does not yet establish clinical indications.