Knee Replacement

The knee is essentially madeup of four bones.The femur of thighbone connecting the hip to the knee. The tibia or shinbone connects the knee to the ankle. The patella (kneecap) is the small bone in front of the knee and rides on the knee joint as the knee bends. The fibula is a shorter and thinner bone running parallel to the tibia on its outside. The Joint acts like hinge but with some rotation.

The knee is a synovial joint, which means it is lined by synovium. The synovium produces fluid lubricating and nourshing the inside of the joint.

Articular cartilage is the smooth surfaces at the end of the femur and tibia. It is the damage to this surface which causes arthritis.


Risks and complications

   > As with any major surgery there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery       outweigh the potential disadvantages.

   >  It is important that you are informed of these risks before the surgery takes place.

Complications can be medical (general) or local complications specific to the knee.

Medical complications include those of the anesthetic and your general well being. Almost any medical condition can occur so this list is not complete.
Complications include:

  •    > Allergic reactions to medications

  •    > Blood loss requiring transfusion with its low risk of disease transmission

  •    > Heart attacks, strokes, kidney failure, pneumonia, bladder infections

  •    > Complications from nerve blocks such as infection or nerve damage

  •    > Serious medical problems can lead to ongoing health concerns, prolonged hospitalization or rarely death.

Local complications

Stiffness in the knee
Ideally your knee should bend beyond 100 degrees but on occasion the knee may not bend as well as expected. Sometimes manipulations are required; this means going to theatre and under anesthetic the knee is bent for you.

Wound irritation or breakdown
The operation will always cut some skin nerves so you will inevitably have some numbness around the wound. This does not affect the function of your joint. You can also get some aching around the scar. Vitamin E cream and massaging can help reduce this.

Occasionally you can get reactions to the sutures or a wound breakdown which may require antibiotics or rarely further surgery.

Infection can occur with any operation. In the knee this can be superficial or deep. Infection rates are approximately 1%. If it occurs, it can be treated with antibiotics but may require further surgery. Very rarely your knee prosthesis may need to be removed to eradicate the infection.

Blood clots (Deep Venous Thrombosis)
These can form in the calf muscles and can travel to the lung (Pulmonary embolism). These can occasionally be serious and even life threatening. If you get calf pain or shortness of breath at any stage you should notify your surgeon.

Damage to nerves or blood vessels
Also rare but can lead to weakness and loss of sensation in part of the leg. Damage to blood vessels may require further surgery if bleeding is ongoing.

The plastic liner eventually wears out over time, usually 10 to 15 years, and may need to be changed.

Cosmetic Appearance
The knee may look different than it was because it is put into the correct alignment to allow proper function.

An extremely rare condition where the ends of the knee joint lose contact with each other or the plastic insert can lose contact with the tibia(shinbone) or the femur (thigh bone).

Patella problems
Patella (knee cap) can dislocate. That is, it moves out of place and it can break or loosen.

Ligament injuries
There are a number of ligaments surrounding the knee. These ligaments can be torn during surgery or break or stretch out any time afterwards. Surgery may be required to correct this problem.

Fractures or breaks in the bone can occur during surgery or afterwards if you fall. To fix these you may require surgery.

Although every effort has been made to explain the complications there will be complications that may not have been specifically mentioned. A good knowledge of this operation will make the stress of undertaking the operation easier for you to bear.

The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages. It is important that you are informed of these risks before the surgery.

You must not proceed until you are confident that you understand this procedure, particularly the complications.


We hope that you have found this information helpful.

Surgery exists as a method of correcting a problem and improving a patient's condition which is everyone's goal.