Distal Clavicle Excision is a procedure used to treat impingement in the shoulder. Shoulder impingement is a painful condition in which the space between structures in a joint narrows, causing parts to rub or pinch that normally would not, which is very painful for the patient. This procedure treats impingement in the acromioclavicular (AC) joint to return the patient to pain-free mobility. The acromioclavicular (AC) joint, which is where the clavicle meets the acromion, sits above the bursa and rotator cuff tendons. Impingement in the AC joint can occur alone or at the same time as impingement in other parts of the shoulder. The AC joint is important in terms of mobility of the shoulder, so damage in the joint can be very painful for the patient. Damage can be caused by trauma, or it can be caused by osteoarthritis, or degenerative joint disease, which can occur in almost any joint in the body. Shoulder osteoarthritis occurs when the cartilage acting as a cushion between the bones in the shoulder joint deteriorates, which can occur from natural degeneration, trauma, injury, or infection. Symptoms of impingement vary, but include inflammation, pain, and limited range of motion. In some cases, there will be acute shoulder pain when raising the arms over the head, laying on the affected shoulder, or reaching backwards.