ACJ Dislocation
The AC or acromio-clavicular joint is the joint between the clavicle (collar bone) and scapula (shoulder blade). It is commonly injured by falling and landing on the point of the shoulder, or landing on an outstretched hand.
There are three ligaments which keep the clavicle attached to the scapula. These are called the acromio-clavicular ligament, the trapezoid ligament and the conoid ligament (see figure below). Together the trapezoid and conoid ligament are called the coracoclaviclular ligaments as they both originate on the coracoid process.
Injuries to the AC joint are graded according to the degree of ligament damage and the amount/direction of the clavicle displacement. Standard practice is to treat Grades 1-3 with physiotherapy and shoulder strengthening, while ACJ injuries of Grade 4-6 typically receive surgery. In some cases Type 3 injuries that do not respond to therapy are managed surgically.
Causes of ACJ Injury
- The injury usually occurs during a fall directly on the point of the shoulder / acromion.
Presentation:
Usually after a fall, sports injury.
Pain and swelling over the ACJ – may present with shoulder drooping and inability to lift arm above head. Examination of skin overlying the collar bone. Check for any nerve or vascular damage.
Diagnosis:
A plain X-ray is used to diagnose the fracture. Sometimes a CT scan may be ordered to assess any other injuries around shoulder.
Treatment:
This depends on patient factors and the degree of displacement.
Vast majority of ACJ injuries are treated non-operatively with short term immobilization.
Non Operative Treatment
- Immobilization. A sling is recommended, keeping the arm immobilized for a few days till it becomes comfortable and the amount of time varies on the degree of displacement, discomfort, age of the patient, and other medical conditions.
- Pain control. Regular non-steroidal anti-inflammatory drugs, including ibuprofen, and/or other pain medications during the healing process.
- Range-of-motion exercises. Gentle range-of-motion exercises may begin as soon as possible and comfortable after the injury.
- Physical therapy. Physical therapy can start 2 to 3 weeks after the injury occurs.
Surgical Treatment Recommended if:
- Nonsurgical treatment does not relieve symptoms.
- Significantly displaced Joint.
- Floating shoulder.
- Patient Choice.
Surgery is performed ‘ACJ Stabilization’ using an open technique and most commonly an artificial ligament is used to stabilize the collar bone onto the coracoid bone. Sometime a keyhole procedure may be undertaken.