Total Knee Replacement surgery

Total Knee Replacement is a proven procedure to address significant pain associated with knee arthritis.

In earlier stages of knee arthritis pain killers, anti-inflammatory medications, physiotherapy and steroid injection can help in pain relief. A knee arthroscopy (key hole surgery) at times can help with pain and mechanical symptoms like locking and giving way. Total knee replacement can relieve pain associated with advanced arthritis and help improve mobility.

Type of anaesthesia for total knee replacement

The surgical procedure is usually carried out under a regional anaesthetic (spinal anaesthetic where your legs are numb for the duration of the operation) and sedation. The procedure can be carried out under a general anaesthetic (where you are asleep). The appropriate anaesthetic is chosen after pre operative assessment and discussion with the anaesthetist. You are made comfortable during the surgery and are not in any pain.

What happens during knee replacement surgery?

Antibiotics are given prior to starting the procedure to reduce the risk of infection. The surgery is carried out under a tourniquet to limit the bleeding during your knee replacement surgery. A cut is made over the front of the knee to expose the arthritic knee.  The arthritic bearing surfaces of the femur (thigh bone) and tibia (shin bone) are removed and metallic alloy components are fitted onto the ends of the bones using bone cement. A polyethylene (plastic) bearing sits between the metallic components. A polyethylene bearing is sometimes placed on the underside of the kneecap depending on the wear of the knee cap. At the end of your knee replacement surgery the skin is closed with metal clips. Local anaesthetic is infiltrated in and around your knee to ensure good pain relief following the procedure.

What happens after knee replacement surgery?

Following your knee replacement surgery, you are made comfortable with pain killers as needed.  Once you have recovered from the anaesthetic, physiotherapists will help you with your walking and knee exercises. You are given walking aids like crutches to help with your early mobilisation. Your knee is x-rayed after the operation to confirm accurate placement of the knee replacement. You should be able to go home within a couple of days of your knee replacement surgery.

What happens after discharge from the hospital?

You need to continue with the exercises to improve the bend in your new knee and to regain the strength in your muscles around the knee. You need to continue with application of ice packs to the knee to reduce the swelling. Two weeks following the surgery your skin clips are removed.  It takes around six to eight weeks for the knee to settle down following the surgery. You will be reviewed in clinic at eight weeks following your knee surgery to ensure you are making good progress.

What can I expect from my knee replacement surgery?

Following your knee replacement surgery, you will be able to carry on with all your daily activities. Though you may not be able to bend the knee fully, you should get good bend with minimal restriction. You may initially find it difficult to kneel but this should improve with time. Exercises and activities causing repetitive impact on the knee should be avoided to reduce the possibility of loosening or wear of the knee replacement. The knee replacement should last for about 15 years in 90% of the patients.

What are the risks of undergoing total knee replacement?

The significant and common risks are as follows:

  • Infection (around 1%): every effort is undertaken to avoid infection by performing the knee surgery in sterile conditions (laminar air flow theatre) and by giving antibiotics around the time of operation.  Despite this infection can still rarely occur.  Infection usually manifests by the incision becoming red, hot and painful, with possible discharge of fluid.  If this infection is superficial (not going deep to the joint) this can usually be treated with antibiotics and an operation to wash the wound. A change of plastic bearing may be needed at times. In case of deep infection, which is fortunately rare, the artificial knee may need to be removed and replaced at a later date after the infection has been controlled.
  • Bleeding: minimised by use of tourniquet during the surgery. Blood transfusion is kept on standby and may be required in the post-operative period.
  • Deep vein thrombosis and pulmonary embolus: deep vein thrombosis (DVT) is a blood clot in the veins of the leg.  The blood clot can go into the general circulation and go to the lungs, which is termed as a pulmonary embolus.  To reduce the risk of DVT you will be given blood thinners as well as stockings on your legs.  One of the best ways to prevent a DVT is to get the calf muscles working by ankle exercises and keeping yourself well hydrated.
  • Swelling: swelling in and around your knee can take few weeks to settle down.
  • Stiffness: The knee can stiffen due to scar tissue on the front of the knee following the knee replacement surgery. Manipulation of the knee under anaesthetic may be needed at times to address significant stiffness.
  • Persistent pain: can occur in 10% of knee replacements due to scar tissue and overactivity of nerves around the knee. This may need input from pain clinic.
  • Loosening, wear and need for revision knee replacement: most knee replacements are expected to last for about 15 years or more.  If there is loosening of the components or wearing of the polyethylene component of the knee replacement the knee may need to be changed (revised).
  • Rare complications include nerve and blood vessel damage, fracture.