What is AC Joint Arthroplasty?
Acromioclavicular (AC) joint arthroplasty, also known as the Mumford procedure or distal clavicle resection, is a surgical procedure performed to mainly treat osteoarthritis of the AC joint or AC joint arthrosis. The procedure involves removal of less than a centimeter of the end of the clavicle nearest to the acromion along with some reshaping of the AC joint to enable pain-free motion of the joint.
Osteoarthritis of the AC joint is a degenerative joint condition defined by loss of cartilage or wear and tear of the smooth, white articular cartilage covering the ends of bones that enable smooth movement of the bones and joints without friction. Wear and tear of the AC joint can occur over time as you age or with repetitive stress activities that affect the AC joint. It is more common in individuals involved in overhead sports activities such as tennis; construction workers; weight lifters; and gym enthusiasts who engage in excessive bench presses and military presses.
Anatomy of the AC Joint
The AC joint is situated at the end of the shoulder where the scapula (shoulder blade) and clavicle (collarbone) join together at a position on the upper section of the scapula called the acromion. The scapula and clavicle bones are held together by ligaments. The joint is enveloped by a group of ligaments called acromioclavicular ligaments to design a capsule that encloses the joint. The shoulder is stabilized by another group of ligaments termed as the coracoclavicular ligaments that hold the clavicle in position by joining it to a bony projection on the surface of the clavicle known as the coracoid process. The joint has a plate of cartilage between 2 bones that help in joint movement. The AC joint enables motion to occur between the scapula and the clavicle as you move your shoulder.
Indications for AC Joint Arthroplasty
Some of the common indications for AC joint arthroplasty include:
- Symptomatic AC joint osteoarthritis
- Impingement of the rotator cuff secondary to arthritic or degenerative changes in the AC joint, such as bone spurs triggering secondary impingement
- AC joint osteolysis or distal clavicular osteolysis, also known as weightlifter’s shoulder; a condition marked by a series of tiny fractures down the end of the clavicle
- Symptoms that interfere with your daily activities, work, and sports and are not responsive to conservative treatment measures for a minimum of six months
