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What Are Artificial Knees
The knee is the largest joint in the body. The knee is made up of the:
- Femur (lower end of the thighbone).
- Tibia (shin bone). The femur rotates on the upper end of the tibia.
- Patella (knee cap), which slides in a groove on the end of the femur.
- Large ligaments, which attach to the femur and tibia to provide stability.
- The long thigh muscles, which give the knee strength.
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The surfaces where these three bones meet are covered with articular cartilage. This smooth substance cushions the bones and permits them to move easily. All remaining surfaces of the knee are covered by a smooth tissue liner called the synovial membrane. This membrane releases a special fluid that lubricates the knee. The fluid greatly reduces friction.
Normally, all of these components work in harmony. But disease or injury can disrupt this harmony. The result can be pain, muscle weakness, and reduced function. |
Materials used for resurfacing of the joint are strong and durable. They produce as little friction as possible. But an artificial knee is not as good as a normal knee. The main long-term problem for artificial knee recipients is loosening, which occurs because the cement crumbles or the bone melts away from the cement. These problems may require repeat knee replacement surgery.
For recipients of a Zimmer NexGen CR-Flex knee, this "long term" problem can occur early. In some cases, loosening occurs after just a year. This early loosening in NexGen CR-Flex knees seems to be occurring at an unusually high rate.
