Shoulder replacement surgery, or shoulder arthroplasty, is generally performed for two reasons: shoulder fractures and shoulder arthritis. If you or your family member are considering this intervention, what are the basics you need to understand?
Modern shoulder replacement surgery originated in the early 1970’s in New York under the teaching of Dr. Charles Neer, and became a widespread option in the 1980’s. The clinical success of this procedure has progressively increased its popularity, with a 300% increase in total shoulder arthroplasty (TSA) procedures in the US between 1993 and 2007, and an estimated 10% further increase annually. Current techniques attempt to reproduce the normal anatomy of the shoulder by replacing the glenohumeral (shoulder) joint with an artificial shoulder made out of metal and plastic. The main shoulder joint is composed of the humeral head (ball-like end of the humerus/upper arm bone) and the glenoid (socket-like extension of the scapula /shoulder blade). Ordinarily, the glenoid and humeral head are covered with articular cartilage, the white smooth tissue that allows joints to articulate and glide smoothly and efficiently. When this tissue wears out or is destroyed through trauma or disease, dysfunction manifested as stiffness and pain results. When severe glenohumeral arthritis is present, X-rays will show complete loss of joint space, bone spurs, and deformity. Initial treatment focuses on decreasing pain with anti-inflammatory medication, cortisone injections, and activity modification, while maintaining strength and mobility through physical therapy or a home exercise program. When these measures are ineffective, surgical intervention with a shoulder replacement may be appropriate.
The procedure itself involves making an incision on the front of the shoulder, dividing overlying muscles, releasing scar tissue to restore flexibility, and replacing the humeral head with an artificial cobalt chrome ball and the glenoid with a polyethylene (plastic) socket. The muscles are repaired and mobility exercises begin immediately after surgery. When performed for fractures, the surgery is more complex, and the goal is to reconstruct the fractured portion of the ball (proximal humerus) around a new implant. This is termed a hemi-arthroplasty, because only the ball, not the socket (glenoid) is replaced. In patients who have irreparable tears in the rotator cuff muscle associated with arthritis, a reverse shoulder arthroplasty, where the ball is converted into a socket and the socket into a ball, is a newer option which often functions better than a traditional shoulder replacement. This is sometimes employed in fracture management in an attempt to improve overhead elevation, which is often difficult to achieve after a fracture.
The results of shoulder replacement surgery for arthritis are excellent, with 90-95% of patients achieving significant improvements in flexibility and strength, and most replacements remaining functional 20 years after surgery. For the treatment of fractures, the results are significantly worse. This is primarily because most patients have a functional shoulder pre-injury, and expectations are to reproduce normal function post-operatively. This is rarely the case, but function is generally much better than it would be with non-operative treatment. Reverse shoulder arthroplasty is a great option for rotator cuff-deficient patients, with most experiencing significant improvement in active shoulder mobility. However, the long term survival of reverse arthroplasty is inferior to standard arthroplasty, and the complication rate is significantly higher.
If you are considering one of these options for your shoulder, be sure that you have pursued the appropriate non-surgical interventions first. If this is the case, and your shoulder dysfunction is significant enough, in your opinion, to warrant a major surgery to alleviate it, then you may be confident in the fact that most shoulder replacements have excellent functional results and long-term survival. There is a cure to your pain.