JOINT REPLACEMENT SURGERY (KNEE, SHOULDER & HIP)

Joint replacement consists of replacing painful, arthritic, worn or cancerous parts of the joint with artificial surfaces shaped in such a way as to allow joint movement.

Arthroplasty is a procedure of orthopedic surgery, in which the arthritic or dysfunctional joint surface is replaced with something better or by remodelling or realigning the joint by osteotomy or some other procedure.

1. 1. KNEE JOINT REPLACEMENT (TOTAL & PARTIAL):
   A total knee replacement is a surgical procedure whereby the diseased knee joint is replaced with artificial material. The knee is a hinge joint which provides motion at the point where the thigh meets the lower leg. The thigh bone (or femur) abuts the large bone of the lower leg (tibia) at the knee joint. During a total knee replacement, the end of the femur bone is removed and replaced with a metal shell. The end of the lower leg bone (tibia) is also removed and replaced with a channeled plastic piece with a metal stem. Depending on the condition of the kneecap portion of the knee joint, a plastic "button" may also be added under the kneecap surface. The posterior cruciate ligament is a tissue that normally stabilizes each side of the knee joint so that the lower leg cannot slide backward in relation to the thigh bone. In total knee replacement surgery, this ligament is retained, sacrificed, or substituted by a polyethylene post. Each of these various designs of total knee replacement has its benefits and risks. 

1. 2. TOTAL HIP REPLACEMENT: Total hip replacement (THR) is a surgical procedure that relieves pain from most kinds of hip arthritis, improving the quality of life for the large majority of patients who undergo the operation. Patients commonly undergo THR after non-operative treatments (such as activity modifications, medications for pain or inflammation, or use of a cane) have failed to provide relief from arthritis symptoms. Most scientific studies that have followed patients for more than 10 years have found "success rates" of 90 percent or more following traditional THR. Distilled to its essentials, THR involves surgically removing the arthritic parts of the joint (cartilage and bone), replacing the "ball and socket" part of the joint with artificial components made from metal alloys, and placing high-performance bearing surface between the metal parts. Most commonly, the bearing surface is made from a very durable polyethylene plastic, but other materials (including ceramics, newer plastics, or metals) have been used. Patients typically spend a few days in the hospital after the procedure (5 to 10 days is most typical), and some patients benefit from a short inpatient stay in a rehabilitation facility after that to help transition back to living independently at home. Most patients will walk with a walker or crutches for 4 to 6 weeks, most will use a cane for another 4 to 6 weeks after that; after that, the large majority of patients are able to walk freely. A bewildering number of different implant designs, bearing surface materials, and surgical approaches have been tried to achieve one seemingly straightforward goal: improving the quality of life for patients who have hip arthritis. As with any important life decision, it makes good sense to get educated on those issues as they pertain to your hip.

3. SHOULDER REPLACEMENT: Shoulder replacement surgery is an option for treatment of severe arthritis of the shoulder joint. Arthritis is a condition that affects the cartilage of the joints. As the cartilage lining wears away, the protective lining between the bones is lost--when this happens, painful bone-on-bone arthritis develops. Severe shoulder arthritis is quite painful, and can cause restriction of motion. While this may be tolerated with some medications and lifestyle adjustments, there may come a time when surgical treatment is necessary. Total shoulder replacement surgery alleviates pain by replacing the damaged bone and cartilage with a metal and plastic implant. The shoulder joint is a ball-and-socket joint, much like the hip joint. The ball is the top of the arm bone (the humerus), and the socket is within the shoulder blade (scapula). This joint allows people an enormous range of motion at the shoulder. When shoulder replacement surgery is performed, the ball is removed from the top of the humerus and replaced with a metal implant. This is shaped like a half-moon and attached to a stem inserted down the center of the arm bone. The socket portion of the joint is shaved clean and replaced with a plastic socket that is cemented into the scapula. 

4. ELBOW REPLACEMENT: Elbow replacement is surgery to replace the bones of the elbow joint with artificial joint parts. The common reason for doing an elbow replacement is pain that affects the activities of daily living. This is followed by instability of the elbow and ankylosis (fusion) of the elbow. The underlying disorders that cause the above problems are Rheumatoid Arthritis, Osteoarthritis, post-traumatic arthritis and other inflammatory conditions. The elbow joint is approached from the back. A skin incision is made and the tissues are carefully dissected out. A nerve called as the ulnar nerve, is identified, dissected and secured. The muscle tendon complex at the back is carefully reflected off the bone, to approach the actual joint. The joint surface is prepared and the two components, the humeral component and the ulnar component, are inserted and linked together with a coupling. The elbow implant consists of two metal stems that are connected by a metal locking pin. This pin passes through the ends of both stems, which are lined with a strong plastic material, serving as a bearing that allows the elbow to bend. The stems are inserted into each of the two prepared canals. A special kind of cement for bones is first injected into the canals to help hold the stems in place. When the cement is hard, the two implant parts are brought together and the pin is inserted to connect them.

HIP RESURFACING

Hip resurfacing is a surgical procedure (a form of arthroplasty) which has been developed as an intervention alternative to total hip replacement (THR). The potential advantages of hip resurfacing include less bone removal (bone preservation), a potentially lower number of hip dislocations due to a relatively larger femoral head size, and possibly easier revision surgery for a subsequent total hip replacement device because a surgeon will have more bone stock available to work with. The potential disadvantages of hip resurfacing are femoral neck fractures (rate of 0-4%), aseptic loosening, and metal wear.