The acromioclavicular (AC) joint is where the collar bone (clavicle) joins onto a bony outcrop of the shoulder blade (scapula). The joint’s stability is provided by the joint’s capsule; the AC ligaments and the coracoclavicular ligaments.
AC joint injuries are classified into three basic levels of severity:
- One: Sprain of the capsule and the AC ligament
- Two: Sprain or complete tear of the AC ligaments with sprain to the coracoclavicular ligaments
- Three: Complete tear of the AC and coracoclavicular ligaments
Fall or trauma on the point of the shoulder.
Signs and Symptoms
- Type One: Pain on touching AC joint and with bringing arm across the body (horizontal flexion)
- Type Two: As above with the addition of a step deformity that can be felt
- Type Three: As above with a step deformity that can easily be seen
Types 1 and 2:
- Avoid lifting, sport and manual labor
- Apply ice, compression and sling for pain relief
- Perform elbow, wrist and finger exercises regularly
- Movement exercises such as fingers up the wall and movement with a broom.
- Pendulum exercises
- Progress movement exercises
- When pain is decreased strengthening exercises of the muscles around the shoulder (rotator cuff)
- Return to lifting, sports and manual labor when there is no pain on touching the shoulder and full movement has returned
- Taping on return to sport
Patients with type 3 injuries should discuss possible operative procedures. Non-operative treatment is usually appropriate for inactive and non laboring patients.