Partial knee replacement

This article will tell you more about partial knee replacement also known as UKA or Microplasty.

Less Pain, Faster Recovery, More Natural Motion.

Arthritis

Healthy joints are covered by a layer of cartilage which is a tough, lubricating tissue that provides smooth, pain-free motion to your joints. Arthritis or ‘joint inflammation’, can be an extremely painful and difficult condition to manage.

When arthritis develops, the cartilage becomes thinner, and eventually wears away down to the bone. Without cartilage, walking is painful and in some cases impossible.

What is Osteoarthritis?

Osteoarthritis or “wear-and-tear” arthritis, is a condition where the surface of the joint is damaged and the surrounding bone grows thicker, resulting in bone against bone friction. This friction can cause severe pain and eventually loss of movement.

Symptoms of osteoarthritis can include:

Painful joints, especially after activity or periods of inactivity
Joint stiffness
Joint swelling
Loss of movement in the joint

What is Total Knee replacement?

The knee joint is one of the largest and most complex joints in the body. It consists of three parts which move and work together to ensure smooth motion and function.

The knee is made up of the lower end of the thigh bone which rotates on the upper end of the shin bone and the kneecap which slides in a groove on the end of the femur. Four large ligaments attached to the femur and the tibia provide stability.

Total Knee Replacement removes the entire surface of the knee joint and replaces that surface with artificial parts. A Total Knee Replacement will consist of the following components:

The femoral component: a metal component on the end of the thigh bone
The tibial component: a metal and plastic liner on the upper end of the shin bone
If needed: a plastic button on the kneecap

What is Partial Knee Replacement?

In the early stages of osteoarthritis, often only one side of the knee is damaged. This is usually the inner side of the knee but, although less common, arthritis can also affect the outer side of the knee.

By having a Partial Knee Replacement before the disease progresses, you may be able to prevent osteoarthritis from spreading, and avoid having to undergo a Total Knee Replacement.

A Partial Knee Replacement, also known as a uni-compartmental knee replacement or Microplasty and will replace only the damaged side of the knee preserving the undamaged cartilage. This will result in a smaller incision, keeping the four natural ligaments and an artificial joint which functions more like the natural knee movement.

Ligament Preservation

By undergoing a Partial Knee Replacement the soft tissues, ACL (Anterior Cruciate Ligament) and PCL (Posterior Cruciate Ligament), are kept intact and are not removed. These ligaments help provide stability, balance, and maintain your natural movement after surgery.

Uni-compartmental Knee Replacement

Depending on how much of your knee is affected by arthritis, surgeons can sometimes perform a partial knee replacement (also known as a unicompartmental knee replacement, UKR) as opposed to a total knee replacement (TKR). In most cases, the clinical team can say whether a UKR is possible before your surgery.

However, the final decision whether to perform a UKR or a TKR is made at the time of your surgery when the surgeon inspects the knee joint surfaces and ligaments.

If you are suitable for UKR, there are a number of potential benefits. These are:

Medical complications are minimised
There is less blood loss during surgery and hence less chance of requiring a blood transfusion
UKR is performed through a smaller incision with less soft tissue disruption
Recovery is faster
Patients often have a very good range of movement in their knee after surgery
We see very high levels of satisfaction in patients who have had this procedure.

What are the risks of surgery?

All operations involve an element of risk. Risks you should be aware of before and after your operation include:

Medical problems
InfectionHospital-acquired blood clots
Ongoing Pain

Stiffness: There is less than 1% risk that the knee joint remains stiff due to scar tissue.

Bleeding
Nerve/Vessel/Tendon damage
Dislocation of bearing
Need for revision/re-do surgery