Acromioclavicular joint injuries
The acromioclavicular joint is the joint between the clavicle and the shoulder blade and is found approximately 2 inches in from the outer point of the shoulder.
Injury to the acromioclavicular joint often happens during a fall onto an outstretched hand or on to the point of the shoulder. Direct impact often happens in contact sports and the most common sport is rugby. The shearing force produced in the acromioclavicular joint produces either ligament damage or a separation of the joint which can result in the appearance of a lump over the top of the shoulder. The most common symptoms include pain at the tip of the shoulder, the shoulder movement limited by pain and shoulder stiffness.
In the short term it is important to use ice over the affected area and to avoid further sport. Physiotherapy can be helpful and also local steroid injection into the inflamed ligaments. For particularly severe or persistent cases it can be helpful to X-ray the joint to determine the extent of separation or mal positioning subluxation and the most difficult cases may be referred to an upper limb surgeon.