Treatment of coracoid process fractures combined with acromioclavicular joint dislocation using clavicular hook plate

The injury mechanism of acromioclavicular (AC) dislocation combined with coracoid process (CP) fracture is not clear, and there is no consensus on its treatment. This study was performed to evaluate the diagnosis of CP fractures combined with AC dislocation and the effectiveness of operative treatment using a clavicular hook plate.Eighteen patients with CP fractures combined with AC dislocation were treated with a clavicular hook plate from May 2012 to June 2021. The patients comprised 10 male and 8 female patients with an average age of 38 years (range, 16-54 years). The injury was caused by falling in 15 patients, traffic accidents in 2 patients, and falling from a height in 1 patient. The Eyres type of CP fracture was type II in 1 patient, type III in 11 patients, type IV in 3 patients, and type V in 3 patients. The Ogawa type of CP fracture was type I in 17 patients and type II in 1 patient. The Rockwood type of AC dislocation was type V in 1 patient, variation type III in 15 patients, and variation type V in 2 patients. The interval from injury to the operation was 3 days (range, 1-7 days). Postoperative complications and CP fracture healing were recorded. Functional assessment at the last follow-up was performed by an independent reviewer using the Constant score and visual analog scale score.All 18 patients were followed up for a mean period of 49 months (range, 12-123 months). Nine patients had acromion osteolysis and 3 patients had CP fracture nonunion (Eyres type II, III, and V in 1 patient each); however, no patients developed shoulder pain, incision infection, limitation of shoulder movement, clinical symptoms of subcoracoid impingement, or AC dislocation relapse. At the last follow-up, the mean Constant score was 99 (range, 94-100).The possibility of CP fracture should be considered in patients with AC dislocation to avoid a missed diagnosis. Fixation with a clavicular hook plate is a feasible treatment for CP fracture combined with AC dislocation and provides a satisfactory outcome. CP fracture healing may be related to the fracture morphology.