Need a new knee?

Walking is difficult and climbing up and down the stairs so excruciating that Rose literally crawls on all fours. Knee pain, like for many women not only in Sri Lanka but also Asia, has been her karume.
"Knee pain is most often due to osteoarthritis," says Consultant Orthopaedic Surgeon Dr. Ananda Perera of the Sri Jayewardenepura General Hospital who has performed 1,000 knee joint replacement operations at his unit, explaining that many other hospitals are also doing the same around the country.

Why does osteoarthritis affect the knee more so than any other joint, in Sri Lankan women? It does affect other joints such as the hip as well but Asians including Lankans are more prone to knee osteoarthritis because of the common "squatting habit" in the toilets, in contrast with western patients who have hip damage, he points out.

Arthritis manifests itself in different forms but osteoarthritis is widespread and the "primary" cause of knee damage is this, with the onset being associated with ageing and the wear and tear of the articular cartilage, MediScene understands.

It is like the brake-lining in the brakes set of a vehicle wearing off, says Dr. Perera explaining that the articular cartilage is the smooth, glistening white tissue that covers the surface of all diarthrodial joints like the knee and the hip. It is essential for the movement of one bone against another, with the ability of bearing large loads.

The "secondary" cause as the name indicates may be due to the mal-union or mal-alignment (not setting the normal way) of the knee when a fracture caused by arthritis heals.

The disease progression of rheumatoid and gout arthritis, the other types, could also destroy the articular cartilage resulting in a painful knee.

• Who is most vulnerable?

Elderly women with medical problems other than osteoarthritis, says Dr. Perera, adding that obesity or overweight and ageing, with a family history of arthritis could make women more vulnerable. Food does not seem to have a link with osteoarthritis.

The symptoms would be knee pain and swelling of the area, with the joint getting deformed as the disease progresses. "Bowing or angulation of the knee will be evident and walking becomes difficult. One or both knee joints can get affected, with one being more acute than the other," says Dr. Perera.

But, cautions this Orthopaedic Surgeon, doctors have to be certain that the pain in the knee is actually generated from the knee itself and not from a hip affected by osteoarthritis. Therefore, investigation of the hip is also vital.

• What Orthopaedic Surgeons would look for:

• Fluid in the knee joint. "Such lubricating fluid is in fact produced as a protective mechanism by the affected knee against the articular cartilage wear-and-tear. Just a serous fluid may indicate the early stages but if there is blood it would be more advanced," he says.
• Extent of deformity and destruction of the joint, the various measurements of which would give a pointer whether surgery is necessary.
• How badly a person's day-to-day activity such as the distance she can walk without pain; whether she needs a walking aid;

whether going up and down the stairs is difficult (the climbing down being more so); whether there is "rest pain" when in bed, watching TV or reading the newspaper; and whether there is a restriction of usual activities like gardening, cooking and marketing.

Dr. Ananda Perera

Stressing that not all patients with knee problems need surgery he recommends other regimens to reduce the pain.

• Weight reduction and changes in diet to support that
• Change of patterns of day-to-day living. Dr. Perera cites the case of a patient whose bedroom is upstairs but the kitchen downstairs and says that she should come down in the morning and attend to all the work, going up again only to sleep. Numerous trips up the stairs should be avoided to reduce the strain, he says.
• Other physical activities such as gentle exercise including walking, cycling or swimming (hydrotherapy) to improve muscle strength and joint functioning.
• Physiotherapy - short-wave, diathermy (use of high frequency electric current to produce heat to either cut or destroy tissue), ultrasound therapy, infra-red light or physiotherapy exercises to help reduce the pain.
• Drugs not only to reduce inflammation (anti-inflammatory) but also to rejuvenate the cartilage. The rejuvenating drugs include glucosamine and chondroitin sulphates.

There are also other disease-specific drugs such as intra-articular injections for rheumatoid and gout arthritis generated knee pain. However, warns Dr. Perera, these injections should be used sparingly, otherwise they could aggravate cartilage wear-and-tear.

Replacing the wear and tear

Three types of operations are performed in knee replacement surgery :

• Alignment Correction Osteotomy is done in the early stages of osteoarthritis where there is a mal-alignment of the knee. Here the knee bone is cut to correct the alignment.
• Arthrodesis used to be performed in the olden days in advanced osteoarthritis which has badly damaged the articular cartilage. Under this procedure, rarely performed now, the damaged cartilage was removed and a bone-to-bone fusion done. "The operation eases the pain but leaves behind a 'stiff joint' which doesn't function as a joint," says Dr. Perera.
• The most common surgery now is knee arthroplasty where the damaged parts are removed and replaced by an artificial joint (prosthesis). The prosthesis is made up of metal (titanium or stainless steel) and special high-grade plastic components (polyethylene) allowing the joint to function normally. Sometimes one or both knee joints are replaced during surgery but in young patients there may only be a need to replace part of a joint. This is called uni-compartment joint replacement.

The surgery lasting about 1-1 ½ hours is usually done under spinal anaesthesia or depending on a patient's need, general anaesthesia. The second day after surgery the patient will be made to walk with a walking frame and physiotherapy will be commenced. As physiotherapy is essential in the recovery process, the patient has to be in hospital for two weeks. The results of knee joint replacement therapy are remarkable, MediScene understands, with Rose's mobility being testament to this.

Meanwhile, hip, shoulder and elbow replacement surgery is also performed at Sri Jayewardenepura Hospital, adds Dr. Perera.