Acromioclavcular joint injuries
The joint between the outer end of the collar bone (clavicle) and shoulder blade (scapula) is called the acromioclavicular joint.
The joint can be injured by a fall on to the point of the shoulder that can disrupt the joint and tear the ligaments which hold the joint in place. This allows the outer end of the collar bone to become prominent beneath the skin which can be seen and felt as a step or bump.
Symptoms of Acromioclavcular joint injuries
Symptoms and signs of an acromioclavicular joint injury are pain over the cape of the shoulder and the arm feels unsupported. There is loss of shoulder movement and prominence of the outer end of the clavicle.
Treatment of Acromioclavcular joint injuries
Mild degrees of damage (subluxation) to the joint are managed simply by resting the arm in a sling for several weeks, and taking analgesia and anti-inflammatory medication. Physiotherapy may be helpful to regain shoulder movement. The pain from the injury often improves in 4-6 weeks but the prominence of the outer end of the clavicle remains but normally does not cause any problem.
When should surgery be considered for an acromioclavicular joint injury?
Surgery should be considered for more severe injuries to the joint (dislocation) in patients with physically demanding occupations. The ligament can be reconstructed soon after the injury and the clavicle held back in place using a variety of techniques which either utilise a screw passed between the clavicle and the scapula, a special “hook” plate that is secured to the upper surface of the clavicle and hooks beneath the scapula or a specially designed “tightrope” suture that holds the clavicle in place.
Late reconstruction of the ligament is also possible by utilising one of the other shoulder ligaments to take over the function of the torn ligaments or by using a synthetic graft.