How do total knee replacements work?

Posted on 16 October 2014

Dr Peter Smith, orthopaedic surgeon at Mediclinic Milnerton, explains how total knee replacements work.

The diseased cartilage is replaced and bone deformity or loss corrected. The cartilage of the femur (the long thigh bone) is replaced by a cobalt chrome prosthesis. ‘The fit is achieved by cutting guides to restore the correct alignment and the femur is sized to match the patient’s anatomy,’ says Dr Smith. ‘The prosthesis is then fixed to the knee with cement that serves as grit. The height of the tibia (the shorter shin bone) is restored with a cobalt chrome base plate, which is cemented to the tibia with a plastic insert. The insert is locked into the base plate with a special locking mechanism.’

What should a patient do afterwards to ensure maximum recovery?
You’ll need to control swelling and pain by resting your leg frequently, applying ice to the knee and raising the leg, Dr Smith says. However, you can resume activity within pain limits as soon as possible. ‘Physiotherapy is very important in the first three months. This will help restore function, strength and motion in the leg.’

Will a knee replacement last forever?
Great strides have been made in knee-replacement surgery since the procedure was first performed and a new knee can last up to 20 years. However, there is no guarantee a prosthesis won’t wear out which is why younger people with knee trouble are encouraged to seek other methods of treatment before a knee replacement is considered.

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Published in Expert Articles

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