What is total knee replacement surgery?

Total knee replacement surgery is the replacement of both sides of a knee joint that is worn out or diseased.

The affected areas are replaced with artificial material fitted onto the surfaces of the femur (thigh bone) and tibia (top of the lower leg).

Causes and needs for surgery

There are many reasons that someone may need to undergo total knee replacement surgery. For the majority of patients, this is due to the joint being damaged by osteoarthritis or rheumatoid arthritis.

You should speak with your doctor if you are experiencing increasing joint pain and stiffness and decreasing daily function, especially if it results in sleep disturbance. Your surgeon will help you understand your options and decide whether surgery is the most appropriate treatment.

The operation

Prior to surgery, your the anaesthetist will discuss your options for anaesthesia.

An incision is made at the front of the knee, splitting muscles in order to work on the joint. Once accessible, the end of the femur closest to the knee is reshaped, removing the worn surface, and resurfaced with a metal prosthesis. The same removal and replacement is done to the tibia closest to the knee. Between the two metal prostheses is a plastic liner. If the knee cap also needs replacing, a plastic button may be inserted under the knee cap surface. Once completed, the incisions are closed and sealed. The procedure typically takes around 45 minutes.

Complications and risks

There are low rates of complications for patients receiving total knee replacements. Medications and exercises are prescribed to reduce risks after surgery. Complications include infection, blood clots, delayed healing, pain, swelling and stiffness.

Infection around the new knee implant is rare, with fewer than 1% of patients affected, but this is serious and may require more surgery. Precautions are taken to reduce the risk of infection.

Small blood clots are quite common after total knee replacement surgery. Major, life threatening blood clots are very rare, with 0.1% of patients experiencing this. Blood thinning medication may result in bruising and occasional wound ooze.

Knee pain and stiffness are expected after surgery, especially during the initial stage of rehabilitation.

Preparation and recovery

Excess body weight puts increased risk on the knee, with potential loosening of the joint during the recovery period. If a patient’s weight is greater than 90kg, weight loss precautions may be considered when preparing for the surgery.

Post-surgery, patients will generally spend between 3-5 days in hospital. A urinary catheter may be needed in the early stages of recovery until the patient is mobile. Physiotherapy is an extremely important part of the recovery process and can begin immediately after surgery, depending on the patient’s progress. Pain, stiffness and discomfort are expected during the initial stages of physiotherapy. Most patients are able to walk without assistance within 4-6 weeks after the surgery. Physiotherapy is required for 4-6 months.

Our Results

We welcome you to view our live reported feedback from patients who have received knee replacements at The Joint Studio. . To compare feedback against the broader industry average, please open the latest report on patient outcomes by the New Zealand Joint Registry.