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Replacement Surgery What is Shoulder Replacement Surgery? (“Shoulder Arthroplasty”) According to the American Academy of Orthopaedic Surgeons, about 4 million people in the United States seek medical care each year for shoulder problems. These conditions range from injuries such as dislocations and fractures to chronic debilitating diseases like arthritis. Shoulder replacement surgery, or “shoulder arthroplasty,” has been available to patients with severe, chronic, debilitating arthritis since the early 1960s. Like other joint replacement surgeries, it is designed to remove diseased portions of bone and joint and replace them with a combination of metal and plastic components, thereby reducing the friction caused by disease and improving range of motion, eliminating the associated pain. Shoulder replacement surgery cannot create a “normal” joint, in place of an arthritic one, but it can allow you to have a greater range of motion without pain, and allow you to return to a more normal schedule of activities. The shoulder joint is a ball and socket joint. The top of the humerus, or upper arm bone, widens and forms the head of the humerus (ball). This head then fits into a shallow socket of the scapula or shoulder blade called the glenoid fossa (socket). During motion, the humeral head moves in the glenoid fossa, providing a wide range of motion. Because of the fit between these two bones, however, very little surface area of the bones are actually in contact at any given moment. The stability of the joint primarily relies on the joint capsule, and a set of short muscles that wrap around the shoulder, keeping the humerus from slipping out of the socket. There are four muscles that come together to form a flat tendon known as the rotator cuff. The tendons of the rotator cuff help stabilize the shoulder by connecting the humerus to the scapula. The primary muscle for power movement of the shoulder is the large deltoid muscle which creates the bulk of muscle about the shoulder. A layer of cartilage covers the head of the humerus as well as the surface of the glenoid fossa of the scapula. In a healthy joint, this cartilage protects the bones against friction during movement. In addition, a cartilage rim surrounds the periphery of the glenoid fossae and provides a slightly deeper socket for the humeral head to rest in. The joint “capsule” is filled with synovial fluid, which also aids in reducing friction. In a normal shoulder, these parts all work together to provide stability during an incredible range of motion. The cartilage-covered surfaces of bone are smooth and shiny, allowing each to move against the other with minimal friction. When any of these shoulder surfaces become diseased, however, the normally smooth surface becomes rough, causing friction and pain. Arthritis causes the cartilage to break down, causing the bones to rub against each other. When this happens, scar tissue and bone spurs may also develop, which leads to further pain and stiffness. Reasons for Shoulder Replacement Surgery? Many different conditions can affect the shoulder and lead to a discussion regarding total shoulder replacement. Some of these conditions include rheumatoid arthritis, osteoarthritis, rotator cuff arthropathy, avascular necrosis, fractures of the shoulder region or a failed shoulder prosthesis (from a previous joint replacement). The most common reason, however, is arthritis. Because arthritis causes the cartilage to break down, it can be the cause of many different associated problems such as the formation of scar tissue. Surgical Procedure for Shoulder Replacement Surgery? First, the surgeon will make an incision along the front of the shoulder, diagonally from the clavicle (the collarbone) to the middle of the upper arm bone. This allows the surgeon to gain access to most of the joint and to perform the procedure without causing damage to the large deltoid muscle of the shoulder. The subscapularis muscle tendon is the only muscle that has to be released from the humerus so that the surgeon will have access to the shoulder joint. Scar tissue and bone spurs can then be removed. Then, bones must be prepared to accept the prosthetic parts. The humerus is cut and reshaped, and the prosthesis is placed in the bone. The humeral head component consists of a smooth metal ball attached to a stem that is inserted down into the humerus. The humeral prosthesis may be a one-piece unit or it may be of two separate parts. The humeral prosthesis comes in many different sizes so that it can be selectively fitted for the different size and shapes of the patient’s humeri. The prosthesis may be secured with bone cement or with the use of the patient’s own bone. If the glenoid fossa is smooth and non-eroded, the surgeon may elect to only insert the humeral prosthesis and this is known as a Hemiarthroplasty shoulder replacement. However, if the glenoid fossa of the scapula is flattened and eroded, then the surgeon will likely reshape the glenoid and then insert the plastic glenoid prosthesis and this is then known as a total shoulder replacement. These new parts will slide smoothly against each other, eliminating the friction and associated pain in the shoulder. Finally, the subscapularis tendon is firmly repaired back to the humerus with heavy sutures. Since the surgery has been done with only the detachment and repair of the subscapularis tendon the rehabilitation program can begin within a day or two of the surgery. Rehabilitation of Shoulder Replacement Surgery? You will be instructed in a graduated rehabilitation program which will first restore motion to the shoulder. At 4-6 weeks you will begin a progressive strengthening program. A successful shoulder replacement can mean a return to activity that you may have given up because of pain, but only after a long recovery process that will require a great deal of work and rehabilitation. If you are not committed to doing daily exercises for your shoulder, than your shoulder will have limited motion even after the surgery. By taking part in an intense rehabilitation, you can expect your new shoulder to have greatly improved motion and very little pain after 6 months. Possible Complications of Shoulder Replacement Surgery? With any surgery, there are potential risks. For shoulder replacement surgery, these include:
A successful shoulder replacement can mean a return to activity that you may have given up because of pain, but only after a long recovery process that will require a great deal of work and rehabilitation. The information provided herein is not intended to be a substitute for professional medical advice. You should not use this information to diagnose or treat a health problem or disease without consulting a licensed physician. © 2000 DynoMed.com, LLC, Indianapolis, IN |