The knee is a "hinge type" joint which is formed by two bones held together by flexible ligaments. The bones are the femur (thigh bone) and the tibia (skin bone). The knee cap (patella) also forms part of the knee joint. It glides over the end of the femur as the knee bends.
The moving parts of a normal knee are covered with a layer of articular cartilage.
An x-ray of the knee normally shows space (the "joint space") between the femur and the tibia.
Keeping Fit With An Arhritic Knee
A recent study suggests that people with knee arthritis may fare better if they force themselves to remain as active as possible, even if the exercise cause some pain. Take pain medicine as necessary before exercising.
There is no evidence that being active will cause a more rapid deterioration of your arthrtic knee. Being active is important for your general health and mental well being. It also keeps your muscles strong, and this will speed your recovery after surgery.
Walking a treadmill or jogging will usually aggravate knee pain. The best all around exercise for you is swimming. The water relieves the stress on your knee.Bicycling (stationary or mobile) is also well tolerated. If you do not have access to an exercise bike or a pool, then walk as much as you can.
Diseases Of Knee Joint
There are number of conditions which can cause arthritis of the knee. The term "Arthritis" literally means inflammation of a joint. Osteoarthritis mainly damages the joint cartilage, but there is often some inflammation as well. The cause of knee osteoarthritis is not known. It is thought to be simply a process of "wear and tear" in most cases.
Rheumatoid Arthritis (R.A.) starts in the synovium and is mainly "inflammatory". It eventually destroys the joint cartilage. Bone next to the cartilage is also damaged, making it very soft.
Symptoms Of Knee Diseases
Arthritis pain coming from the knee joint may be felt in the front, the back, or the sides of the knee. Not all "knee pain" necessarily comes from the knee joint itself. Hip pain frequently radiates down the thigh to the knee.
Sometimes knee pain is so prominent in patients with hip disease that the patient (and sometimes even the physician) can be fooled into thinking that the problem is in the knee when in fact the problem is in the hip!
Other knee symptoms include catching, giving way (buckling), locking, swelling, a painful limp, creaking and a decreased distance the patient can walk because of pain.
The movement that is possible in the knee joint will gradually becomes less; the knee may not straighten out all the way or may not bend fully, or both. The leg may become increasingly "bow-legged" or "knock- kneed" with time.
At night the knee pain may awaken the patient when he or she turns over while sleeping.
Total Knee Replacement Surgery
In actual fact, this procedure is more akin to dentistry and a better term would be knee Resurfacing.
A thin layer of bone is removed from the damaged surface of the femur (thigh bone) using special instruments which remove the correct thickness of bone. The removed bone is then replaced by a thin layer of metal, approximately the same thickness as the bone which was removed. In a similar fashion the upper end of the tibia (skin bone) is removed and is replaced with a wafer of plastic.
The back part of the knee cap (patella) may also be resurfaced with a piece of plastic. The three parts are attached to the bone by means of a "bone cement" (methylmethacrylate). After the knee has been replaced, the metal "cap" covering the end of the tibia, preventing bone from rubbing on bone and giving relief from pain.
The plastic is high density polythylene a material which has a very low wear-rate and a very low frictional resistance when rubbing against the highly polished metal surface.
Other Surgical Treatment Alternatives
- Unicompartmental Knee Replacement : Each knee actually has two "compartments"- an inner and an outer compartment.Not infrequently one compartment will be severely affected by arthritis while the other may be almost normal. In these circumstances you may best be served by having only the "bad" compartment replaced (called a "unicompartmental knee replacement" or a "uni"). The advantages of uni include a better range of motion, quicker recovery and somewhat more lenient long -term restrictions.
- Arthroscopic Surgery :Mild to moderate cases of knee arthritis frequently benefit from an arthroscopic "clean-out". But the benefits are usually temporary.
- Synovectomy : Is mainly of benefit in selected cases of rheumatoid arthritis. Unfortunately, the synovium can grow back and the arthritis can then progress.
- Osteotomy : Osteotomy of the knee is usually reserved for younger patients who have mild disease and bow legs, and who can still straighten their knee completely.
- Knee Fusion : This is a procedure in which the femur bone is made to fuse to the tibial bone. This results in a permanent and complete stiffness of the knee joint.
Knee arthritis is not a life-threatening condition : the procedure is "elective". There are possible complications associated with knee replacement surgery. The decision to have the operation is a highly personal matter, and only you can make that decision.
- If your disability is great enough, the potential benefits are worth the risk. If your arthritis is responding to conservative measures, and you can still walk long distances without a cane, you don't need a knee replacement.
- Once you have knee arthritis it will never get better.
- The rate of further deterioration varies greatly from person to person.
- You will never need a knee replacement if you are willing to live with the pain.
- More than 96% of patients who have had a knee replacement operation have no major complications.
