Knee Replacement

What is a total knee replacement?

Knee replacement surgery, also known as arthroplasty, is generally regarded as an effective treatment for end-stage knee arthritis. It results in an improved knee function and significantly relieves severe pain caused by degenerative joint diseases. All knee replacement procedures are generally divided into 2 major groups, depending on whether the knee is replaced totally or partially. When trying to better understand the mechanism behind total knee arthroplasty, knowing the anatomic complexity of a knee is useful . The knee is often compared to a hinge which allows the knee joint to flex, extend and allow limited rotation of the lower leg.

Structurally it resembles three separate joints: a slightly rounded end of the thigh bone forms 2 separate articulations with a slightly hollow end of the shinbone which has the mobile kneecap on top. The most common indication for total knee replacement is severe osteo-arthritis that affects all surfaces of these synergic joints and causes pain which is unresponsive to medical management.

• During the procedure, the patella is laterally dislocated and the knee is exposed in flexion.
  The affected joint tissue is surgically removed and replaced by a knee prosthesis which consists of three separate components.
• The end of a thigh bone is replaced with a femoral component made out of a metal plate which corresponds to the natural shape of the bone.
• The tibial component, which consists of a metal tray covered with a layer of plastic that moves against the surface of the femoral segment, replaces the top surface of the lower leg bone.
• Patella component covers the back part of the kneecap and is made out of plastic for it to glide over the front of the knee. Due to this reason the patient is advised not to kneel on the operated knee as the plastic covering of the patella may resurface.

These significant structural changes are directly responsible for the main complaint after knee replacement surgery, which is stiffness and a lingering sensation of a foreign body placed inside the joint. All in all, a total knee replacement is one of the most successful examples of innovative surgery and has resulted in substantial quality-of-life gains for people with severe joint problems.

What is a partial knee replacement?

In comparison to a total knee arthroplasty, partial knee replacement may be defined as a less invasive surgical approach for patients with only moderate knee joint diseases. A great majority of degenerative joint diseases primarily affect the medial compartment of the knee joint. This is because a fibrous cartilage between the surfaces of the medial tibio-femoral articulation, also known as a medial meniscus, is relatively thinner and experiences greater pressure whilst walking etc. The damaged component of the knee is replaced using the same method as in the total knee arthroplasty but without affecting the healthy parts of the joint. However, as flawless as partial knee replacement may sound, its biggest potential drawback is incomplete pain relief. The success of the surgery depends entirely on choosing the right candidate and carefully evaluating the extent of disease.

Preparation for surgery

Careful preparation for knee replacement surgery is an important part of the procedure itself as it determines the success of the surgery and the quality of post-op recovery.

Hospitalisation and what to expect during the first days after surgery

After the surgery a patient is expected to stay in the clinic for 2 to 3 days. If a patient underwent general anesthesia, it is absolutely normal to experience some mild side effects on the first day after the procedure. On the following day a postoperative patient is encouraged to start moving and walking with a walker or crutches. In the beginning, it requires a lot of will and effort to start walking again, but it will pay off in the form of faster recovery. Upon discharge from the hospital, a patient should be able to take short walks, bend one’s knee up to 90 degrees and climb up and down a few steps with some extra help.

The importance of physiotherapy

It could be said that half of the success of a knee replacement surgery depends on the post-op physical therapy. A physiotherapy exercise routine may be either home-based or monitored by the health professionals in rehabilitation facilities. Studies have shown that light to moderate regular exercises show short-term improvements in the patients’ physical function, whereas more intensive ones have positive long-term outcomes. In order for a certain therapeutic approach to give good results, the right combination of physiotherapy methods should be selected for each individual patient.