Joint pain affects 15% of the population worldwide. Up to two-thirds of joint pain is due to osteoarthritis. Local figures however, are more alarming. Results of a recent survey on knee pain showed that 50% of Singapore residents suffering from knee pain at some point in their lives. In addition, 73% of the population is at risk of developing osteoarthritis of the knee.
The Normal Knee
The normal knee is lined by smooth cartilage. The function of this cartilage lining the knee joint is to provide shock absorption, even distribution of forces across the knee as well as to provide a smooth gliding surface for movement at the joint. Cartilage is composed of cartilage cells, water and specialised proteins.
The Osteoarthritic Knee
In a knee affected by osteoarthritis, the cartilage lining the joint surface is thinned, roughened and even cracked. In addition, the composition of the cartilage is also altered such that it is more susceptible to damage. Cartilage of this nature has obviously lost its ability to perform its key functions of absorbing shock and providing a smooth, even gliding surface during joint movement.
In addition to changes in the cartilage, the bone underlying the cartilage also undergoes changes (cyst formation and growth of bone spurs). In the long run, as the disease process progresses, other than joint pain, the knee also becomes progressively stiffer and deformed.
Initial Treatment for Osteoarthritic Knee
The predominant symptom which sufferers of knee osteoarthritis experience is pain. This pain is worsened by walking and stair-climbing. It affects quality of life as the sufferer is limited in the activities he/she can participate in.
Based on the local survey, our population suffers for an average of 13 months before seeking treatment for knee pain secondary to osteoarthritis. Initial treatment of knee osteoarthritis is as follows –
Medications used commonly include anti-inflammatories and paracetamol. These medications help with the pain of osteoarthritis. Results from the use of supplements such as glucosamine and chondroitin are mixed. However, as they rarely cause any harm, these supplements can be used in initial treatment of osteoarthritis.
Physiotherapy and Exercise
Physiotherapy serves to improve the flexibility of the joint as well as to strengthen the muscles controlling the movement of the knee. This improves function. In addition, exercises such as swimming and walking also helps with mobility and strength. At the same time, weight-loss goals can also be achieved. High-impact exercises should be avoided.
Viscosupplementation for Initial Knee Osteoarthritis
Joint fluid has an important role to play in lubrication and function of the knee. In osteoarthritis, the concentration of hyaluronic acid in the fluid is reduced. Viscosupplementation is the process in which hyaluronic acid is injected into the arthritic joint. Beyond simple mechanical lubrication, this fluid also has anti-inflammatory and analgesic (painkilling) properties. It also stimulates the knee to produce its own hyaluronic acid in greater quantities. This method of treatment is associated with better outcomes in early arthritis as compared to late stage arthritis.
Surgery for Late Stage Knee Osteoarthritis
In late knee osteoarthritis, when other measures have not been effective in alleviating pain and improving quality of life and function, surgery is necessary. Knee replacement is commonly performed surgery and is associated with excellent results in term of pain relief and improvement of function. In general, the patient is able to walk the very day after the procedure and is able to walk without the assistance of walking aids by six weeks.
While knee pain is a common condition, it is prudent to seek a professional opinion if it lasts beyond a week or two. The result of treating osteoarthritis in early stages is usually better than seeking treatment once it has reached an advanced stage.