Joint reconstruction involves rebuilding the architecture of a joint to restore its proper function and to reduce a patient’s pain. Some forms of joint reconstruction include total hip replacement, total knee replacement, ACL (anterior cruciate ligament) reconstruction, and chondroplasty.
The hip is a ball-and-socket joint, in which the “ball” is the femoral head—the upper end of the thighbone or femur. It fits into the acetabulum, or “socket,” in the large pelvis bone. Cartilage lines the joint to cushion the ends of the bones and allow them to glide more easily. Conditions such as osteoarthritis and rheumatoid arthritis can interfere with the proper functioning of the hip joint.
In total hip replacement, physicians replace the damaged bone and cartilage with prosthetic components. They remove the damaged femoral head and place a metal stem into the hollow center of the femur. They then use a metal or ceramic ball to replace the femoral head. They replace the damaged cartilage lining the acetabulum with a metal socket, holding it in place with screws or cement. Surgeons then place a plastic, ceramic, or metal spacer between the prosthetic ball-and-socket surfaces to provide a smoothly gliding surface.
Recently, some surgeons have begun to perform so-called minimally invasive hip replacement involving smaller incisions and shorter recoveries. The ideal candidate for this type of procedure has a normal body weight, is 50 years old or younger, and is generally healthy.
The knee joint comprises the lower portion of the femur; the upper end of the tibia, or shin bone; and the patella, or kneecap. Total knee replacement involves resurfacing the bones. Physicians replace the damaged cartilage at the ends of the femur and the tibia, as well as a small amount of underlying bone, with metal components that re-create the surface of the bone. In some cases, they resurface the underside of the patella with a plastic disk. They insert a plastic spacer between the metal pieces to create a smoother surface.
Another type of knee reconstruction involves rebuilding the ACL in the center of the knee. A torn ACL can allow the knee to collapse during activity. ACL reconstruction involves an “autograft” using tissue from the patient’s body or an “allograft” using tissue from a donor. To reconstruct the ACL, surgeons remove the torn ligament, make tunnels in the bone, pass the transplanted tissue through these tunnels, and then attach the new ligament to the bones.
In some cases, the cartilage of the knee is damaged. Cartilage cannot repair itself, so it requires surgical repair. Chondroplasty involves reshaping the knee’s surface and removing any damaged pieces of cartilage by cutting, scraping, or lasering it away. In some cases, surgeons can perform chondroplasty arthroscopically using tiny incisions.