The AC Joint or acromioclavicular joint is the joint between the outer end of the clavicle (collar bone) and the acromion (tip of the shoulder blade).
What do you mean by AC Joint arthritis?
This means arthritis of joint between the outer end of the clavicle and the acromion. The common types of arthritis which can affect the AC Joint are:
Post Injury Arthritis
What is osteoarthritis?
This is the “wear and tear” arthritis that one generally sees with age. It is a degenerative joint disease and the most common type of arthritis seen in the AC joint. As a person ages, the water content of the cartilage (which covers the bone surfaces in the joint) decreases and the cartilage becomes less resilient. It thus becomes susceptible to break down. Breakdown products released from the cartilage can cause inflammation in the joint. Bones spurs or “osteophytes” can form on the margin of the AC joint. These changes together with the inflammation can result in significant pain.
What is rheumatoid arthritis?
This is a generalised condition resulting in inflammation of the joint lining (synovium). This can occur at all ages and tends to affect multiple joints in the body. Symptomatic rheumatoid arthritis of the shoulder is typically seen between the ages of 35 and 55 years and is more common in women. Such patients often have associated arthritis of the hand and elbow.
What is Post-injury arthritis?
Post injury arthritis or post-traumatic arthritis is the type of osteoarthritis that occurs following an injury such as a partial dislocation or fracture of the outer end of the collar bone. Such injuries can result in irregularity of the AC joint surface. As a result this increases the wear and resulting in premature arthritis.
What are the symptoms of AC Joint arthritis?
The main symptom of AC Joint arthritis is pain in the shoulder in middle aged persons particularly those involved in physical professions or sports involving overhead use of the arms. The pain is usually felt over the top of the shoulder and tends to be worse on moving the arm above shoulder level for example when reaching up to get something of the top shelf of a cupboard. As the disease progresses there may be significant pain at rest and at night. Limitation of movement in the shoulder or stiffness may result due to pain.
How is AC Joint arthritis diagnosed?
The history and physical examination usually gives the orthopaedic surgeon enough information to make the diagnosis. This is confirmed by taking x-rays of the AC Joint. Narrowing of the joint and bone spurs may be seen. If there is any doubt about the source of the pain, then a local anaesthetic injection into the joint may be performed. If the injection relieves the pain, it will confirm that the AC joint is the pain source.
How is AC joint arthritis treated?
Treatment depends upon a number of factors such as previous treatment, age, general health, and degree of pain and disability. The initial treatment of AC jointarthritis is usually non-surgical. This may include:
Modification of activities to avoid provoking pain.
Anti-inflammatory tablets and painkillers.
If nonsurgical treatment is not successful in adequately reducing pain then surgery may be indicated.
What are the surgical treatments available for shoulder arthritis?
The surgical treatment is excision of the AC joint as a daycase. This can be done either arthroscopically or by open surgery:
Keyhole (arthroscopic) surgery: this involves excising a few millimetres of bone from either side of the joint and any degenerate tissue from within the joint.
Open surgery this involves doing the same procedure by making a 4-5cm incision over the top of the joint.
What is the recovery time?
The shoulder does not need to be immobilized in a sling. Exercises are started straight away. Physiotherapy commences within days and return to work for sedentary occupations is usually within 1-2 weeks. It may take 3 months to return to sports etc. The success rate for relief of pain is about 90%.