You don’t realize how often you raise your arms overhead during everyday activities until you can’t do it anymore. Pain and loss of function are no strangers to people with arthritis. One place this arthritis occurs is the acromioclavicular (AC) joint.
The AC joint is located at the end of the collarbone (clavicle) in front of the shoulder. The AC joint is formed by the clavicle and acromion. The acromion is a piece of bone that starts in the back as part of the shoulder blade and curves to form a bony roof over the shoulder.
When the arm is raised overhead, the top (head) of the humerus bone in the arm slides and glides in the socket to allow smooth motion. The humeral head normally drops down as the arm is raised up to avoid hitting the acromion. Changes from arthritis, pain, and muscle weakness may keep the humerus from dropping. If the head of the humerus doesn’t drop down in the socket, the bone comes up against the acromion, pinching the tissues in between. This condition is called subacromial impingement.
In this study, patients with both AC arthritis and subacromial impingement had surgery to repair the problem. The doctor removed about one-quarter of an inch (1 cm) from the clavicle at the AC joint. A special tool was used to burr away the bone from the front on the underside. This approach avoids damage to the nearby cartilage and soft tissues. The authors think this is the key to good results.
Patients in this study did have good results. They had pain relief and increased motion and function. They also reported improved work function that lasted for years after the operation. Patients who were involved in sports said that their athletic performance was improved, too.
The authors conclude that patients who are held back by a combination of AC arthritis and subacromial impingement can get help. Resecting the end of the clavicle takes the pressure off the AC joint to help avoid the pain of impingement.