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A partial knee replacement only replaces the joint surfaces in one compartment of the knee. We use it most commonly on the medial (inner) side. The artificial knee is made of metal components that are secured to the bone using special bone cement or uncemented. A mobile bearing made of polyethylene is inserted between the fixed metal components and acts as the gliding surface.


Partial knee replacement is an excellent solution for the pain caused by arthritis in one compartment of the joint. In the first instance though you should try to manage your pain with lifestyle changes, exercise and medication. You can find further advice on this here. If you still cannot walk as much as you would like because of pain or cannot sleep the time has come to consider surgery.

The NJR decision support tool can help you get an idea of what you can expect from the surgery.


  • Preparing for your operation

    • We need to make sure you are as fit and prepared as possible to minimise the risk of complications and to ensure a speedy and smooth recovery. You will have a pre-assessment to identify any correctable abnormalities such as high blood pressure, anaemia​ and diabetes. We advise that you stop smoking and try to loose weight if applicable. If you are obese you may need a total knee replacement instead of a partial. If your BMI is 40 or more we may have to postpone your surgery until you can loose some weight.

    • We will ask you to take part in a joint replacement class which is run by our physiotherapists. This is an invaluable resource to prepare you for your joint replacement journey from pre-surgery exercises to rehabilitation afterwards.

  • Surgical procedure

    • Knee replacement requires a general or spinal anaesthetic and the consultant carrying this out will discuss with you which one is best considering your circumstances and preferences.

    • During surgery an 8-10 cm cut is made over the front of the knee and the joint is exposed. The damaged joint surfaces are removed, the bone is ​prepared for the artificial components which are fixed with or without bone cement. The mobile bearing is then inserted. To conclude the operation the soft tissues and the skin are carefully closed. Learn more.

  • Recovery

    • We aim to get you back on your feet and walking on the day of your operation. We will keep you comfortable using the least possible amount of pain medication. Our physiotherapists will guide you through the process of how to get in and out of bed and use any walking aid you may require. All being well you can go home after one night in hospital.
      We will give you an exercise program for home and our physiotherapists will assess your progress regularly. You can walk and use your knee as you are comfortable.


  • Partial vs Total knee replacement. A partial knee replacement is a smaller operation carried out through a smaller incision so you will have less pain, bleeding, swelling and a quicker recovery. The knee feels more natural and you are likely to have better range of movement. If you need revision surgery later this is usually straight forward. This may be the case If the arthritis progresses in the remaining parts of the knee. 

  • Pain relief. The knee joint is more painful than the hip and takes longer to settle down. You need to exercise the knee gently so the inflammation and swelling can gradually subside.

  • Range of movement improves within a few weeks.

  • Your mobility should improve gradually and if there are no other limiting conditions you should be able to walk a few miles after 6 weeks.

  • Correction of bowed knee. The surgery should improve the overall alignment of the knee.


  • Fracture of the thigh bone or the shin may occur during surgery or later such as after a fall. 

  • Persistent pain can occur and sometimes does not settle completely even after months of rehabilitation.

  • Infection is a major complication which may require further surgery.

  • Significant bleeding is uncommon.

  • Nerve injury is rare. 

  • Blood clots can form in the deep veins of the leg or cause a blockage of the arteries of the lung. 

  • A sensitive scar usually improves over time.

  • Serious anaesthetic complications are rare.

The overall benefit of surgery should far outweigh the risks, but it is important that you understand these in detail so you can make an informed decision. Learn more.

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