KNEE ARTHRITIS

In the normal knee joint the ends of the bones are covered with articular cartilage. This surface has special characteristics that make it an ideal joint surface. The articular cartilage needs to be distinguished from the meniscus, commonly called “the cartilage” The meniscus lies around the margins of the joint and fills in the gap between the rounded end of the femur and the relatively flat surface of the tibia.

Osteoarthritis is a condition where the articular cartilage breaks down and is essentially worn away leaving the underlying bone exposed. On an X-ray this appears as a loss of the space between bones.

There are many factors that can contribute to the development of osteoarthritis. Some individuals probably have a genetic predisposition to the condition, as it does seem to run in some families. Females are more at risk of developing osteoarthritis than males. Obesity is a very important contributory factor as the biomechanics of the knee are such that the effect of extra weight is magnified in the knee joint. Injuries to the knee can also contribute to the development of osteoarthritis. The treatment of osteoarthritis depends on the severity of the condition, the symptoms, the lifestyle of the individual, as well as their age and general health. In general, treatment can be divided into non-surgical and surgical options. As a basic principle it is always better to try all non-surgical options before proceeding down a surgical path.

NON-SURGICAL TREATMENT

Non-surgical treatment starts with ensuring that there is adequate strength in the muscles around the knee and getting one's weight back to a normal level. Obviously it can be difficult for many patients with osteoarthritis of the knee to exercise because of their pain. However, riding an exercise bike is a good way of strengthening the knee and will help in efforts to lose weight. However, dietary intake also needs to be modified and it may be helpful to seek specific advice from a dietician. 

Using simple painkillers can be a very effective way of relieving symptoms and improving function. Paracetamol should be the mainstay of pain relief.  The total dose should not exceed 4 grams per day (8 standard 500mg tablets). This will help get over morning stiffness and pain and relieve night pain, two of the most troublesome symptoms of osteoarthritis.

Anti-inflammatory medications can also provide good relief of symptoms, both pain and swelling. However, they can all be associated with significant side-effects including indigestion and stomach ulcers, aggravation of high blood pressure and heart disease, and impairment of kidney function. They should therefore not be used indiscriminately and preferably only for short-term benefit. If your knee causes you most difficulty with activities such as golf or tennis, one strategy is to take anti-inflammatory medication on the day you are playing sport and perhaps the following day but then not again until you play sport the next time.

There are a number of so-called nutraceutical preparations that have become very popular. These include glucosamine, chondroitin sulphate, fish oil and green-lipped mussel extract (Lyprinol). Some individuals find that they get good relief from these types of preparations but it is difficult to predict who will respond positively to them. At present there is little in the way of good quality scientific evidence to support their use. Fortunately they do not seem to have any significant side effects, so there is little harm in trying them. It would seem logical to try only one at a time. If it is unclear whether the preparation is helping, then it is probably worth taking it for 2 to 3 months and then ceasing it. If your symptoms do not deteriorate once you stop taking the preparation then there is little reason to recommence it. There is no convincing evidence to suggest that one formulation of glucosamine is better than another, or whether the addition of chondroitin sulphate provides an additional benefit.

SURGICAL OPTIONS

Knee Replacement involves cutting the bone ends and applying a metal or polyethylene component to the surface. Usually both sides of the joint are replaced. One can either replace all parts of the knee, which is a total knee replacement or just one part of the knee, which is a partial replacement. Partial replacement can only be used for certain patterns of osteoarthritis. Replacement procedures are only compatible with low impact sporting activities. Golf, social or doubles tennis, cycling, and snow skiing are reasonable whereas running, basketball, netball, or any type of football should not be considered, because of the risk of premature wear and loosening of the prosthesis.