Distal clavicle osteolysis / Weight lifters shoulder
The Acromioclavicular Joint (ACJ) is a small joint made up of the acromion bone, which is part of your shoulder blade, and the outer end of your clavicle (collar bone). It is easily palpated with your finger as it lies 1 – 2 cm from the top outer edge of your shoulder. Because of its location, problems with the joint can give rise to pain in both the shoulder and neck.
Acromioclavicular joint, or distal clavicle, osteolysis is an unusual condition in which the outer end of the clavicle (distal clavicle) undergoes multiple minor stress fractures secondary to repetitive injuries. As a consequence of these injuries, the bone is eroded at a faster rate than it can be repaired and as a result, bone erosion or ‘osteolysis’ occurs. This results in the loss of bone form the distal clavicle.
Causes & Risk factors
The Acromioclavicular joint undergoes significant loading when undertaking lifting activities at or above, shoulder height. Distal clavicle osteolysis usually affects patients under the age of 40 years old, with those undertaking overhead sporting activities on a repeated basis especially prone to this type of condition. In particular, weightlifters, avid gym goers, rugby payers and overhead workers such as builders and plasters are particularly prone to developing this condition.
The diagnosis is essentially made on clinical grounds. Pain is often most noticeable when the arm is raised above shoulder height and when the arm is taken across the front of the body thus compressing the Acromioclavicular Joint. The ACJ is also often very painful to palpation.
X-rays can be used to demonstrate the loss of the distal clavicle. This undergoes erosion and therefore the bone of the distal clavicle is often lost secondary to erosion or osteolysis. The use of ultrasound or MRI scans can be used to further investigate the shoulder where a significant degree of oedema (swelling) within the distal clavicle is often noted.
There are a number of different techniques to address the pain from ACJ osteoarthritis:
- Conservative treatment comprising of rest, activity modification and the use of anti-inflammatory medications.
- Physiotherapy; this can be used to improve the range of painful movement to the shoulder however its successfulness is often dependant on the degree of pain already experienced and if rest and activity modification has also been undertaken.
- Injection treatments; the space between the acromion and the distal clavicle can be injected with local anaesthetic and Cortisol. The anti-inflammatory component of the injection can reduce swelling and pain and can be used in conjunction with physiotherapy to aid recovery. However, it may only provide temporary relief and is also dependant on the shoulder being rested so that aggravating activities are avoided.
- Arthroscopic distal clavicle excision; If the pain is resistant to non-operative treatments then surgery is often necessary. The aim of the surgery is to arthroscopically remove any degenerative tissue within the joint, as well as a small amount of the distal clavicle that might be further irritating the joint. This ‘key-hole’ procedure is performed through three small incisions.