The acromion or roof of the shoulder joins with the clavicle (collarbone) and a tough ligament in the front of the shoulder (coracoacromial ligament) to form an arch over the rotator cuff. Four small muscle tendon units blend together to form a ‘cuff’ over the ball of the upper arm bone (humerus) and assist you in rotating your arm, thus, the term “rotator cuff”. The rotator cuff muscle and tendons pass beneath the acromioclavicular or “AC” joint. The AC joint may be injured, or damaged over time often due to repetitive lifting activities. Painful degenerative arthritis of that small joint may result from chronic pushing, pulling, and overhead lifting activities and is often termed, “weightlifter’s shoulder”. The arthritic process may result in the formation of relatively large spurs, which can insult the underlying rotator cuff tendons (‘impingement’). Exam reveals painful overhead motion of the shoulder as well as tenderness at the AC joint, which is often very prominent. X-rays show the extent of spur formation and arthritis that is present. Ice, non-steroidal anti-inflammatories, injections and physical therapy may be effective in managing the symptoms for a time. When conservative measures fail, arthroscopic surgery is often indicated. During an outpatient procedure, a shaver and burr can be alternately introduced through tiny incisions and used to remove spurs, and when necessary, a 1/3 inch segment of the end of the clavicle to relieve the pain due to the arthritic surfaces rubbing against each other. A sling is worn for 3 – 5 days, after which range-of-motion exercises are initiated. After 4 – 6 weeks, muscle strengthening begins. Full recovery requires 3 to occasionally 4 months.