Osteoarthritis of the knee is a common condition where the articular cartilage breaks down and essentially wears away, leaving the underlying bone exposed.
Many factors can contribute to the development of osteoarthritis. The risk increases with age and females are more likely to develop the condition than males, although it isn’t understood why.
Some people may have a hereditary disposition to the disease. Obesity is another important contributory factor given the effect that extra weight has on the knee joint.
Prior knee injuries including damage to the meniscus or articular surface, or a tear of the anterior cruciate ligament, could also contribute to its development.
Symptoms often develop slowly and worsen over time. They can include:
The knee is the largest and most complex joint in the body. It is formed by the two large bones of the lower limb, the femur (thigh bone) and the tibia (shin bone). The patella, or kneecap, articulates with the femur at the front of the knee and the fibula joins with the tibia on the outer side of the knee.
The ends of the bones are covered with a type of gristle called articular cartilage, which is designed as a bearing surface. The knee also comprises ligaments, tendons and muscles, which control movement, and meniscus, discs that act as shock absorbers when the bones move.
Treatment depends on the severity of the disease and can range from quadriceps strengthening exercises to surgical procedures. Riding an exercise bike is a good way to strengthen the quadriceps muscle while burning calories, which can help in efforts to lose weight. Dietary intake may also need to be modified.
Simple painkillers such as paracetamol can help relieve morning stiffness and night pain. Other options include anti-inflammatories, nutraceuticals such as fish oil or glucosamine, or cortisone or viscosupplement injections. While these options provide pain relief, they will not affect the progression of osteoarthritis in the long term.
Surgery options include an arthroscopy, realignment procedures and joint replacement.
An arthroscopy is a small and simple procedure where a small camera on a tube, called an arthroscope, is inserted into the knee joint through a small incision. The camera is connected to a monitor to guide the surgeon using thin instruments. The procedure is often used to diagnose issues without the need for open surgery and can enable the removal of unstable articular cartilage and fragments floating in the joint.
Realignment procedures, or osteotomies, involve cutting the tibia or femur bone and changing the overall alignment of the leg with the aim being to take weight off the part of the knee that is affected by osteoarthritis.
Replacement involves shaping or cutting the bone ends and applying a metal or polyethylene component to the surface. A total knee replacement replaces all parts of the knee while a partial replacement may replace just one part.
Joint replacement is generally a last resort option as the patient will then be limited to low impact physical activity due to the risk of premature wear and loosening of the prosthesis.