The Morrison study shows that the outcome of impingement symptoms varies with patient characteristics. Younger patients ( 20 years or less) and patients between 41 and 60 years of age, fared better than those who were in the 21 to 40 years age group. This may be related to the peak incidence of work, job requirements, sports and hobby related activities, that may place greater demands on the shoulder. However, patients who were older than sixty years of age had the "poorest results". It is known that the rotator cuff and adjacent structures undergo degenerative changes with ageing.
Surgery may be used to treat a rotator cuff disorder if the injury is very bad or if nonsurgical treatment has failed to improve shoulder strength and movement sufficiently. Subacromial smoothing involves shaving bone or removing growths on the upper point of the shoulder blade ( acromion ). It removes damaged tendon and bursa from the joint . The surgeon may also remove small amounts of bone from the underside of the acromion and the acromioclavicular joint (acromioplasty). The goal is to take away roughness while keeping as much of the normal supporting structures as possible. This surgery creates more room in the subacromial space. With more space, the rotator cuff tendon is not pinched or irritated and can glide smoothly beneath the acromion.