The main joint in the shoulder is the glenohumeral joint, which allows for a lot of the motion in the shoulder. The acromioclavicular joint, or AC joint, is just above the glenohumeral joint. The AC joint is formed by the meeting of the distal clavicle and the acromion, and it is responsible for a lot of the stability in the shoulder. Injuries to the AC joint are common in a lot of sports, especially those that require overhead movements, are played on a very hard surface, or involve rough physical contact. Listed below are three common AC joint injuries.
1. AC Joint Separation
If the ligaments that hold the AC joint together are torn, it can cause the bones to separate. This is caused by trauma to the shoulder, which can occur from a sudden impact like a tackle or by landing on an outstretched arm. Symptoms of AC joint separation include swelling, bruising, pain, and a noticeable loss in range of motion. As the bones shift, bumps on the shoulder may be visible. Conservative treatment begins with rest and immobilization. Your doctor may prescribe anti-inflammatory medication. Physical therapy exercises can help to restore strength the previous range of mobility, but if the tear is very severe, surgery may be needed.
2. AC Joint Arthritis
If the tissue in the AC joint begins to deteriorate, it is called AC joint arthritis or AC joint arthrosis. This degeneration is caused by overuse of the shoulder, commonly from repetitive overhead motions, or as a result of injury. Symptoms of AC joint arthritis include pain over or in front of the joint and arm movement accompanied by popping or clicking. Rest, cortisone injections, and non-steroidal anti-inflammatory medication may be prescribed by your doctor. Use of an immobilizing device like a brace or splint and adherence to a regimen of physical therapy may be used to treat this condition. If the degeneration is very severe, surgery may be necessary.
3. AC Joint Fractures
If the distal clavice or the acromion is fractured by a sudden impact, it can cause damage to the cartilage in the AC joint. This can contribute to AC joint arthritis down the road, but it can also cause pain and mobility issues. AC joint fractures are common in sports, particularly cycling, where the surface landed on is likely to be very hard. Diagnosis of a fracture is confirmed with an X-ray and treated with immobilization of the affected area for a set amount of time. If the fracture is accompanied by impingement syndrome or if bone shards are present, surgery may be needed. Physical therapy and rehabilitation exercises are very important in recovering from a fracture. Range-of-motion exercises and strengthening exercises can help you heal properly, so you're able to return to previous activities. If a fracture heals incorrectly, it can cause pain and mobility problems down the road.