Acromioclavicular joint (ACJ) injuries
What is it?
The acromioclavicular joint (ACJ) is the area where your collarbone meets your shoulder blade. An ACJ injury, therefore, is any break in a bone that makes up the shoulder joint, such as the proximal humerus (top of the arm), the clavicle (collarbone), or scapula (shoulder blade). The latter acts as a strut between the sternum (breastbone) and scapula, keeping the arm to the side of the body.
Why does it occur?
A direct blow sustained during a fall, during contact sports, or as a result of being in a road traffic accident, are sufficient to cause fracture in these bones. A less traumatic impact may cause injury in older patients who may have weaker and less robust bones.
Scapula fractures are much less common due, to the protection of the chest wall and surrounding muscles. As a result, this fracture will be as a result only of a high energy trauma.
What are the symptoms?
Severe pain, swelling and difficulty in moving the arm are the most common symptoms of such an injury. Depending on which bone is affected, a deformity may be evident, with surrounding bruising and a grinding sensation when attempts are made to move the arm.
How is it diagnosed?
In addition to taking a history and a physical examination, your surgeon will take radiographs of the shoulder to accurately determine the diagnosis. Occasionally a CT scan or MRI will be needed, in order to obtain a more detailed view of the fracture pattern, and to plan the best course of treatment.
How is it treated?
Plenty of rest, painkillers and refraining from activities which aggravate the pain and loss of function. If these have no effect we would suggest a steroid injection into the joint, which can help with relieving pain. Steroid injections mask pain, and work for 3 to 12 months, but some patients receive no benefit, in which case surgery is considered.
Pain in the ACJ is due to the ends of the bones making contact with each other, so surgery would involve the removal of a portion of the end of the collarbone. The AC joint is one of the few joints in the body that you can live without a portion of the bone making up the joint. Surgery is usually done via a small incision or several small incisions using an arthroscopic (keyhole) technique.
The One Orthopaedics team specialists
Consultant Orthopaedic Surgeon FRCS (Tr&Orth), Shoulder, Elbow, Hand and Wrist