Acromioclavicular(AC) joint injuries

Netcare Sunninghill Hospital
Tel: 011 257 2179

Sandton MediClinic Hospital
Tel: 011 463 8830 | 011 463 8833

Acromioclavicular

joint injuries

Normal anatomy of the shoulder

The shoulder is made up of three bones: The upper arm bone (humerus), the shoulder blade (scapula), and the collarbone (clavicle).

The shoulder is a ball-and-socket joint: the ball, or head, of the humerus fits into a shallow socket (glenoid) in your shoulder blade.

The rotator cuff is a group of four muscles that come together as tendons to form a covering around the head of the humerus. The rotator cuff attaches the humerus to the shoulder blade and helps to lift and rotate your arm. The rotator cuff also helps to secure the humeral head within the shoulder socket.

There is a lubricating sac called a bursa between the rotator cuff and the bone on top of your shoulder (acromion). The bursa allows the rotator cuff tendons to glide freely when you move your arm.

The Acromioclavicular (AC) joint is located at the tip of the shoulder where the acromion portion of the shoulder blade (scapula) and collarbone (clavicle) join together. The AC joint is not as mobile as the large main shoulder joint and only moves when your arm is overhead or across the chest (adducted). The joint is partly filled with a thick pad of cartilage, known as the meniscus, which allows the joint to move. The AC joint is stabilised by its capsule and additional ligaments called the coraco-clavicular ligaments and acromio-clavicular ligaments.

The Acromioclavicular Joint is usually injured by a direct fall onto the point of the shoulder. The shoulder blade (scapula) is forced downwards and the clavicle (collarbone) forced upwards damaging the ligaments and joint capsule. The degree of damage to the
joint is traditionally classified by the joint displacement and injury to the ligaments which support the AC joint.

Treatment:

Traditionally the grade of the injury determines the treatment, however the evidence for this is poor. Nowadays, we treat according to the symptoms – i.e. pain and functional limitations – with guidance from the literature around the relevance of the grade of injury.

Considerations for surgery:

1. 1. Most people with ACJ injuries can cope, unless an overhead worker or a high
    demand athlete.
  2. The long-term outcomes are similar with or without surgery
  3. Traditional techniques carry a failure rate of approximately 20%

The main goals of treatment, whether surgical or nonsurgical, are to achieve a pain-free shoulder with full range of motion, normal strength and no limitations in activities. The demands on the shoulder will differ from patient to patient, and these demands should be
taken into account during the initial evaluation.

Type I and 2:

Most types I and 2 AC joint separations are treated non-surgically. 27% of conservatively treated types I and 2 AC joint separations may require further surgery at 26 months after injury (Mouhsine et al).

Type 3:

Type 3 injuries are usually evaluated on a case-by-case basis, taking into account hand dominance, occupation, heavy labor, sporting requirements, scapulothoracic dysfunction, and the risk for re-injury. In a review of 1172 patients, 88% who were treated operatively and 87% who were treated non-operatively had satisfactory outcomes. In this study some patients needed further surgery (59% operative versus 6% nonoperative). Pain and range of motion were not significantly affected by the decision to have surgery or not.

Type 4, 5 & 6:

Complete AC joint injuries (types 4, 5, and 6) are usually treated surgically because of the significant morbidity associated with persistently dislocated joints and severe soft tissue disruption. The shoulder presents with a severe step-off deformity due to downward displacement of the arm and shoulder blade (scapula) and upward displacement of the
collarbone.
For unstable AC Joints and symptomatic complete dislocations (Grade 4, 5 & 6) injuries the collarbone and shoulder blade need to be re-aligned and fixed in place

Surgical technique:

ACJ ligament reconstruction can be done as either an ‘open’ surgical technique or through a ‘keyhole’ arthroscopic technique. There are numerous different methods described to fix or reconstruct the ACJ ligaments. The newest and most commonly used techniques involve using an artificial ‘ligament’ which is then passed between parts of the shoulder blade in the front and the collarbone. This artificial ligament supports the joint while scar tissue forms in place of the damaged ligaments.

ACJ Arthritis

Arthritis of the AC joint is a degenerative disease of the acromioclavicular joint between the collarbone (Clavicle) and the acromion part of the shoulder blade (scapula). Arthritis may be due to normal age related wear and tear of the cartilage within a joint, or it may occur due to a previous injury or infection within the joint. This results in a loss of cartilage and over time the joint can wear out. Arthritic joints become larger, and develop bony spurs around the joint. As with arthritis of other joints in the body there is often pain
and swelling in the joint but it may also be completely painless.

Causes:

The principal cause of AC joint arthritis is overuse. As a person uses his/her arm and shoulder, stress is placed on the joint. This stress produces wear and tear on the cartilage, the cartilage becomes worn over time, and eventually arthritis of the joint may
occur. Another cause is an old injury to the AC joint, such as ACJ Dislocation. Any activity that can put pressure on the joint, either normal or excessive, may eventually cause the arthritis condition.

Persons who must use their arms for extended periods of time are susceptible to AC joint arthritis. Constant overhead lifting, such as is engaged in by weightlifters or construction workers who work overhead can increase the risk of arthritis. Other susceptible
individuals are athletes participating in contact sports or engaging in any activity which may result in a fall on the end of the shoulder. Any blunt force to the shoulder in the course of work, household activities or accident may cause, over time, arthritis of the AC
joint.

Treatment:

1. 1. 1. 1. Rest
      2. Physiotherapy – to prevent any further stiffness and regain range of motion
      3. Painkillers and anti-inflammatories
      4. Injections into the painful joint – this usually provides good temporary relief.
      5. Surgery

Surgical management

Required for advanced disease, with pain not controlled with injections or analgesia. Surgery usually involves removal of the AC joint.

For more information please read the booklet below

Netcare Sunninghill Hospital
Tel: 011 257 2179

Mediclinic Sandton Hospital
Tel: 011 463 8830
or 011 463 8833