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A knee replacement (also called knee arthroplasty) might be more accurately termed a knee “resurfacing” because only the surface of the bones are actually replaced.
Knee Replacement Surgery Procedure
There are four basic steps to a knee replacement procedure.
- Prepare the bone. The damaged cartilage surfaces at the ends of the femur and tibia are removed along with a small amount of underlying bone.
- Position the metal implants. The removed cartilage and bone is replaced with metal components that recreate the surface of the joint. These metal parts may be cemented or “press-fit” into the bone.
- Resurface the patella. The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button. Some surgeons do not resurface the patella, depending upon the case.
- Insert a spacer. A medical-grade plastic spacer is inserted between the metal components to create a smooth gliding surface.
Reasons to Have Knee Replacement Surgery
The most common cause of chronic knee pain and disability is arthritis. Although there are many types of arthritis, most knee pain is caused by just three types: osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis. Osteoarthritis, a degenerative joint disease that affects mostly middle-aged and older adults, may cause the breakdown of joint cartilage and adjacent bone in the knees. Rheumatoid arthritis occurs when the immune system, the body’s normal defenses, attacks the synovial membrane causing inflammation. This can result in pain, stiffness, swelling, and loss of function. Traumatic arthritis, arthritis due to injury, may cause damage to the cartilage of the knee. These injuries can happen immediately like in a car crash or accumulated damage over time from an old injury (sports for example). 1