Introduction

Knee arthritis is a common cause of pain and immobility.  The most common cause is osteoarthritis, generally known as a wear and tear of the joint. It commonly occurs in people above 60 years of age.  In the younger population it can be due to trauma or inflammatory joint disease (such as rheumatoid arthritis). 

Total knee replacement

The knee joint is a hinged joint, but with some freedom of movement.  In knee replacement surgery, the knee is replaced with two or three components.  The thigh bone (femur) is capped by a metal component.  The shin bone (tibia) is covered with a metal component covered by a plastic (polyethylene) insert, which allows the smooth hinged movement of the knee metal components. 

The knee cap (patella) may be replaced with a plastic (polyethylene) component which glides over the metal femoral component. 

Before Surgery

Dr Stavrou will undertake a number of tests to ensure that you are suitable to undergo surgery.  You will require a prior meeting with your anaesthetist for further assessment.  Anti-inflammatory medications such as Aspirin, Brufen, Voltaren, etc. should be stopped 10 days before surgery.  If you are taking any blood thinners, for example, Warfarin, Plavix or Iscover, stopping these should be discussed Dr Stavrou.  It is ideal if smoking can be ceased prior to surgery.  

It is also advisable to prepare circumstances at home prior to your surgery, as there will be a period of recovery and rehabilitation following your surgery.  Arranging for family and friends to assist you in the home setting is highly recommended. You should ensure that there is adequate clearance in the home to enable you to use a walking stick or walking frame.

It is important that you organise family and friends to assist you with transport, as you will not be able to drive for at least 6 weeks.

Surgery

Surgery requires a general or spinal anaesthetic. On the first day after surgery, the staff will assist you with standing up and you will commence walking.  Further exercises will be introduced with the assistance of your physiotherapist.  Once you are independently mobile, you are able to be discharged from the hospital.   This is usually around 4 to 6 days from your surgery. 

Occasionally, patients do require a longer course of rehabilitation and this can be undertaken at a rehabilitation centre.  Most patients are independently mobile with the aid of a walking frame or two walking sticks on discharge from hospital.

After Surgery

You will require blood thinners to lessen the risk of blood clots, even after discharge from hospital.

It is important to maintain mobility once you are discharged from hospital.  Most people return to low impact activities such as walking, golfing, bowling and swimming at 3 months following their surgery.   High impact activities, such as jogging or running are not allowed.  Whilst your knee has been replaced, it is artificial, and like all materials will fail under excessive use.  

Driving is usually resumed when comfortable, particularly when you are able to brake in an emergency, usually at the 6 to 8 week mark following surgery. 

There should be no kneeling or squatting and you may have trouble climbing stairs.  Most patients will be able to achieve 90 degrees of flexion (bending of the knee) to allow for sitting comfortably.

Returning to work can be dependant upon the activities of your employment, but is usually resumed at anywhere between 4 weeks to 3 months following surgery.

Physiotherapy

Physiotherapy usually takes place within the hospital. Outpatient physiotherapy is recommended, this may include hydrotherapy (pool exercises) once your wound has healed.

Risks of Surgery

Risks include bleeding, requirement for blood transfusion, infection, wound healing problems, stiffness, limp, blood clots (deep vein thrombosis and pulmonary embolism), damage to nerves and blood vessels.

All joint replacements will wear out as time goes on, but about 90% of joint replacements will last for up to 15 years.  Failure from loosening and wear increases with the level of activity.  Failure of your knee replacement may require replacement with a new prosthesis (revision surgery).