Anatomy

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

Causes

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

Home Treatments

Types 1 and 2:

First phase

• 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

Second phase

• 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

Type 3:

Patients with type 3 injuries should discuss possible operative procedures. Non-operative treatment is usually appropriate for inactive and non laboring patients.