AC Joint disorders

Common Conditions of the Shoulder

Acromioclavicular Joint (ACJ) Disorders

Anatomy

SLAP Lesion
Acromioclavicular Joint (ACJ) Disorders

This joint is located at the end of the clavicle (collar bone) at the top of the shoulder. There are two common conditions affecting this joint.

  1. Dislocation / Subluxation
  2. Arthritis

Dislocation

Dislocation of the joint usually occurs following a fall onto the hand or elbow or onto the point of the shoulder. More commonly the joint partially dislocates, this is known as a subluxation.

What are the signs and symptoms?

Severe pain is felt over the shoulder and any attempt to lift the arm up or carry anything makes this worse. A bump may be felt over the top of the shoulder. This is usually very tender.

How is the diagnosis made?

The doctor will listen to the description of events and examine the shoulder. X-Rays will also be taken. Occasionally the patient will be asked to carry a weight in the affected hand during the X-Ray. This is designed to stress the joint and make the dislocation more obvious.

What is the initial treatment?

The joint can sustain a range of inuries from a sprain (which hurts but with little deformity) to a full dislocation (which hurts more and has an obvious deformity). The sprains and the majority of dislocations require only a sling to rest the joint for a few days followed by exercises to recover the range of movement. It takes about 6 weeks for the discomfort to settle and a bump will always remain but otherwise they heal well. Rarely the severe dislocations will require surgery to put the joint back together and to repair the torn ligaments. This fortunately is uncommon.

Some of the acute dislocations benefit from stabilisation, particularly in the very thin, the heavyset and overhead athletes who find that the lose power.

More commonly the injuries ar treated conservatively and only the few which become symptomatic require surgery.

Acromioclavicular Joint stabilisation surgery

Arthritis

As with arthritis in other joints of the body this is something which usually affects older people but this is not absolute. Previous injury does not necessarily mean that arthritis will develop.

What are the signs and symptoms?

Pain is felt in the region of the joint. This is usually a dull pain at night, which is made worse by lying on that side. Sharp pain is felt when reaching overhead, particularly at the top of the reach. Symptoms of rotator cuff impingement may also be experienced.

How is the diagnosis made?

The doctor will listen to the description of events and examine the shoulder. X-Rays will also be taken to exclude the shoulder joint as a cause of the problem. Injections of local anaesthetic into the tissues near the joint (the sub-acromial bursa) or the joint itself may be used.

What is the initial treatment?

The initial treatment depends on the symptoms. If the symptoms are purely related to the ACJ an injection of steroid may be beneficial. This may be repeated several times if necessary.

If the symptoms are from both the rotator cuff and the ACJ then steroid injections may be used for both of these sites.

What if the initial treatment fails?

If the symptoms do not improve then it may be necessary to surgically remove the joint. This can be done either through a standard "open" operation or using the arthroscope.

AC Joint Excision