RadiopaediaAcromioclavicular Joint Injury

This deep-dive into acromioclavicular joint injuries unpacks everything a physician needs to know about these prevalent injuries.

Acromioclavicular joint (ACJ) injuries, mostly traumatic, can occur across all ages but are more frequent in males aged 20-40, often related to contact sports. Patients usually present with vague shoulder pain and swelling, but visible deformity is rare. Two mechanisms contribute to ACJ injuries: direct, resulting from a direct blow or fall onto the shoulder, and indirect, arising from a fall onto an outstretched hand or elbow.

Imaging is crucial for diagnosis. The Rockwood system, among others, categorizes these injuries into six types. Plain radiographs, including an axillary view, generally suffice for accurate grading. However, in certain scenarios, CT or MRI might be necessary. In case of an injury suspicion with initial normal radiographs or contemplating surgical intervention on a type III injury, additional weight-bearing stress views can be beneficial.

Indications of ACJ injury on a plain radiograph may include soft tissue swelling, acromioclavicular joint widening, increased coracoclavicular distance, and superior displacement of the distal clavicle. The treatment choice hinges largely on the patient’s age, lifestyle, and injury type. Conservative management typically applies to types I and II injuries, surgical treatment to types IV, V, and VI, and type III injuries undergo varied treatment.

Moreover, post-injury complications may lead to osteoarthritis. Surgical complications can include hardware migration and infection. It is critical to analyze several features such as soft tissue swelling, degree and direction of subluxation of the clavicle, any fractures present, and glenohumeral joint alignment. Also, inspect the image periphery to ensure no rib fracture, pneumothorax, or incidental lung, mediastinal, or osseous lesion is present.