KNEE REPLACEMENT

Knee Replacement Surgery:

Knee arthritis is very prevalent to our country as compared to the western population. It’s because of our social and cultural habits. Knee replacement surgery is done for the painful, arthritic knee joint. It’s all about pain management and quality of life.
The knee is the largest and complex joint in the body. The knee joint is important for walking and most of our day to day activities. The knee joint is formed between the lower end of the femur (thigh bone), the upper end of Tibia (Leg bone) and patella. The ends of all these bones are covered by a cushion called cartilage so that movement occurs between the soft cartilages over the other soft cartilage.
There are smooth discs in between the bones known as menisci. These act as “shock absorbers” of the joint.
Two inside and two outside strong ligaments hold the bones together and provide stability. Quadriceps and hamstring muscle group give the knee strength. Inside the joint, there is a membrane called as a synovial membrane.

Arthritis:

Arthritis is of many types:

1. Osteoarthritis – This is usually the most common type in India. It’s degenerative arthritis because of wear and tear of the cartilage. Arthritis sets in when the cartilage over the bone ends get eroded and the eburnation bone starts rubbing against the bone giving rise to pain.

2. Secondary/Post-Traumatic Arthritis – This is because of the previous injuries leading to fractures and ligament tears. It’s mechanical type and causes being the weight bearing forces passes in an abnormal fashion. Because of the abnormal stresses and forces there occurs the accelerated wear and tear leading to the arthritis

3. Rheumatoid And Seronegative Spondyloarthropathies – This is the primary inflammatory type. The primary pathology lies within the synovial membrane. The pathologic membrane damages the cartilage leading to pain and arthritis.

Clinical Features

1. Pain

The main feature of arthritis is a pain. Pain occurs every time when there are movement and weight bearing. The eburnation bone ends rubs over each other every time there with the movement.

Difficulty and pain in getting up from the chair
Pain on squatting down, kneeling
Pain while climbing up and down the stairs
Pain and difficulty on long-standing

2. Deformity

Bowing of the leg and knee joint. Varus is more common deformity in India as compared to Valgus, which is more common in the western world.

Total Knee Replacement

Knee replacement is the surgery where this degenerated and eroded bone ends are cut with minimum thickness and are replaced by metal and poly. Thus a new joint is formed between the poly and metal.
There are different types of the Endoprosthesis used for the surgery. Following are the types according to the design-

1. All Poly-
Where the tibial component is all polyethene. It can be done where the bone stock is good. There is the advantage of avoiding one source of friction between the metal base plate and polyethene. Secondly, it’s cheaper. But results are not good if done in osteoporotic bones.

2. Metal Back –
This is by enlarging largest done type.

3. High-Flexion Knee –

Design modifications are done so that patient may get maximum knee bending postoperatively. Of course, the amount of knee bending you get after surgery depends mainly on the knee bending range patient has before surgery and amount and quality of physiotherapy done after surgery.

4. Improved Material – Continuous research is going on for the invention of the bearing material which will last longer. Presently we do have different combinations of material used for the bearing surfaces. Many companies have come up with latest designs, which will give the feeling of the natural knee joint to the patients.

Complications Of Surgery

Knee replacement is a major surgery and not without complications and risks. There can be complications during the surgery, in an early postoperative period and late postoperative period. Of course, every single precaution to avoid it is the key but it’s important to be aware of it and to seek timely medical attention

Infection:

One of the dreadful complications is an infection. Its incidence is low and average percentage is less than two. It can be acute, (can occur while in the hospital or after you go home). Or it can be late or secondary (infection spread through the bloodstream from any other focus in your body).
We take maximum preventive measure for that. It starts from your preoperative preparation. A thorough checkup is done to rule out any infection focus in yourbody. Even dental caries, ear infections, skin infection or urine infections can be a serious concern.
A patient is at high risk for infection when the immunity is at compromise, like a patient on immunosuppressant, steroid, or low protein and albumin levels. Rheumatoid patients, anaemic patients are also at little higher risk.
In the operation room, we take enough precautions. This operation should be done in the state of art operation room (which has a laminar flow system). Operation team wears disposable gowns and space suits. Prophylactic antibiotics are used.
If unfortunately, the infection spreads in the surgical site then within two weeks re-exploration, lavage, exchange of poly and intravenous antibiotics can help.
Deep vein thrombosis:
Blood clots may form in the leg and calf veins. It can be dangerous if the clot gets dislodge and travel to lungs.
We take enough precautions to prevent this:
Early weight bearing and calf exercises are started on the same day.
Mechanical compression devices are given along with. We also use a blood thinner injections/tablets for about 2 to 3 weeks.
Anti-embolic stockings are given to the patient for use up to 6 weeks after the surgery.
Other complications:
Superficial/cutaneous nerve damage:
Cutaneous nerves supplying the skin over the incision site are usually damaged. They are very insignificant but may cause numbness around the wound for some time. Of course, it does not affect your course of physiotherapy after the surgery.

Deep vein thrombosis:

Blood clots may form in the leg and calf veins. It can be dangerous if the clot gets dislodge and travel to lungs.
We take enough precautions to prevent this:
Early weight bearing and calf exercises are started on the same day.
Mechanical compression devices are given along with. We also use a blood thinner injections/tablets for about 2 to 3 weeks.
Anti-embolic stockings are given to the patient for use up to 6 weeks after the surgery

Other complications:

Superficial/cutaneous nerve damage:

Cutaneous nerves supplying the skin over the incision site are usually damaged. They are very insignificant but may cause numbness around the wound for some time. Of course, it does not affect your course of physiotherapy after the surgery.