Os acromiale is failure of acromial ossification during development that may lead to pain and dysfunction. Prevalence rates of os acromiale in the general population range from approximately 1% to 15%, and these nonunions are associated with subacromial impingement and rotator cuff tears. The etiology of os acromiale is not fully understood; however, studies hypothesize that a genetic disposition leads to anomalous development and ossification or that mechanical strain and overloading across the acromion during development leads to aberrant formation. Clinically, patients with os acromiale may report pain or symptoms caused by two general mechanisms. Nonanatomic downsloping of the os acromiale may lead to subacromial impingement and rotator cuff pathology. Instability at the site of failed ossification may lead to inflammation at the nonunion site and pain directly over the os acromiale.

This video demonstrates internal fixation of os acromiale via cannulated screws and tension band wiring. The video discusses the anatomy and pathogenesis of os acromiale and details treatment options for patients with symptoms. The video provides a review of the literature and recent data on treatment outcomes. The video discusses the case presentation of a 25-year-old man with symptomatic os acromiale after shoulder arthroscopy, and reviews the indications for surgical management. Initially, the os acromiale is débrided from the subacromial space arthroscopically, followed by superior débridement through a strap incision. The two fragments are fixed with cannulated screws, and demineralized bone graft is placed in the void. Tension band wiring is performed to achieve final fixation. The surgical technique, postoperative protocol, and pearls and pitfalls are discussed. Excellent closure of the os acromiale was maintained at short-term follow up, with substantial improvement in pain and dysfunction. Cannulated screw fixation and tension band wiring is a successful treatment option for the management of symptomatic os acromiale. Careful review of the indications for surgical management is necessary to avoid treatment of patients with asymptomatic nonunions. Internal fixation of os acromiale via cannulated screws and tension band wiring results in good clinical outcomes and appropriate bony healing.