Knee Revision

The knee is made up of four bones. The femur or thighbone is the bone connecting the hip to the knee. The tibia or shinbone connects the knee to the ankle. The patella (kneecap) is the small bone in front of the knee and rides on the knee joint as the knee bends. The fibula is a shorter and thinner bone running parallel to the tibia on its outside. The joint acts like a hinge but with some rotation.

The knee is a synovial joint, which means it is lined by synovium. The synovium produces fluid lubricating and nourishing the inside of the joint. Articular cartilage is the smooth surfaces at the end of the femur and tibia. It is the damage to this surface which causes arthritis.

Why does a knee need to be revised?

• Pain is the primary reason for revision. Usually the cause is clear but not always. Those knees without an obvious cause for pain, in general, do not do as well after surgery.

• Plastic (polyethylene) wear. This is one of the easier revisions where only the plastic insert is changed.

• Instability which means the knee is not stable and may be giving way or not feel safe when you walk.

• Loosening of either the femoral, tibial or patella component. This usually presents as pain but may be asymptomatic. It is for this reason why you must have your joint followed up for life as there can be changes on X-ray that indicate that the knee should be revised despite having any symptoms.

• Infection-usually presents as pain but may present as swelling or an acute fever.

• Osteolysis (bone loss). This can occur due to particles being released into the knee joint which result in bone being destroyed.

• Stiffness-this is difficult to improve with revision but can be helped with the right indications.