Clinical significance for new type of coracoid process fractures associated with acromioclavicular dislocation on CT three-dimensional reconstruction

Abstract

To observe the computerized tomography (CT) imaging manifestations of coracoid process fractures associated with acromioclavicular(AC) joint dislocation and make classification and summary, and explore a new classification of coracoid process fracture combined with acromioclavicular joint dislocation. The medical records of patients with the acute traumatic coracoid process fractures associated with AC joint dislocation who had undergone surgical management with clavicular hook plate fixation between May 2012 and June 2021 were retrospectively reviewed. Patients with fractures or dislocations of other parts of the ipsilateral upper limb, which affect the treatment and prognosis, or with chronic shoulder diseases on the affected side, which affect the function of the shoulder joint, were excluded. Eighteen patients were enrolled, including 10 males and 8 females, aged from 16 to 54 years old at the time of injury. The causes of injury were fall in 15 cases, traffic accident in 2 cases, and high fall in 1 case. The time from injury to operation ranged from 1 to 7 days. The morphology of coracoid process fracture and its corresponding relationship with scapula were observed on CT three-dimensional reconstruction images, and the reduction of coracoid process fracture was observed. The results were classified according to different manifestations and outcomes. A total of 18 patients with 18 shoulders were included according to the Inclusion and exclusion criteria. Three manifestations of coracoid process fracture associated with acromioclavicular joint dislocation were observed on CT three-dimensional reconstruction images. One case was typeⅠ(avulsion fracture, coracoid process shape remained general intact), and the coracoid process fracture failed to self-reduction after AC joint reduction and fixation;Fifteen patients with type Ⅱ(hinged fracture, in which one side of the coracoid process fracture remained attached to the scapula or was less displaced than the other side of the fracture) had spontaneous reduction after AC joint reduction and fixation, even 7 of them had coracoid process fracture anatomical reduction;In 2 cases of type Ⅲ (translational fracture, coracoid process fracture with approximately parallel profile), coracoid process fracture failed to self-reduce after AC joint reduction and fixation. The new type of coracoid process fractures associated with acromioclavicular dislocation on CT three-dimensional reconstruction provides an overview of the injury involvement of coracoid process fracture associated with AC joint dislocation, better understand of the nature of the disease, and a reference for clinical diagnosis, treatment and prognosis to the surgeon. Based on the fact that most coracoid fractures especially hinged fractures have spontaneous reduction after AC joint reduction and fixation, we believe that simple fixation of the AC joint is feasible and satisfactory for coracoid process fractures with acromioclavicular joint dislocation, and no surgical intervention is required for coracoid process fractures.