Shoulder Replacement

About Shoulder Replacement

Shoulder replacement, or shoulder arthroplasty, replaces the damaged surfaces of the glenohumeral joint. Anatomic total shoulder arthroplasty replaces the humeral head with a metal ball and resurfaces the glenoid socket with a plastic component, reproducing the normal anatomy; it requires a functioning rotator cuff and is mainly used for osteoarthritis. Reverse total shoulder arthroplasty swaps the ball and socket, placing a ball on the glenoid and a cup on the humerus. This changes the mechanics of the joint so that the deltoid muscle can raise the arm without a functioning rotator cuff, making it the treatment of choice for rotator cuff tear arthropathy, massive irreparable cuff tears and many complex fractures of the upper humerus in older adults. The reverse design was developed by the French surgeon Paul Grammont in the 1980s and has become widely used. Hemiarthroplasty, replacing only the humeral head, is used less often than in the past. The number of shoulder replacements has increased substantially in recent decades. After surgery the arm is protected in a sling for a period, followed by gradually progressive rehabilitation. Pain relief is usually good, and range of motion after reverse arthroplasty is functional though more limited in some directions. Complications include instability and dislocation, infection, fracture around the implant, nerve injury, loosening of components and scapular notching, a radiographic finding of wear on the shoulder blade beneath the reverse implant that often causes no symptoms.