Arthritis is accepted by most people as an inevitable consequence of the aging process.  With the remarkable improvements in health care, nutrition, and hygiene that have occurred in the last seventy years, people in First World countries are living longer than ever before.  This means that conditions which develop insidiously over a long life span, like arthritis and joint degeneration, were not seen on a large scale until recent years.  I often say tell clients who are in their 40s or 50s that many middle-aged people develop knee problems because the shelf life of a human knee is approximately 40 years - the same as life expectancy used to be!

The incidence of osteoarthritis of the knee has also been influenced by participation in sports, as this condition often develops secondary to traumatic injuries such as ligament tears.  The proliferation of young women in the 1980s in injury-producing sports which were previously not widely available to females, such as basketball, soccer, softball, volleyball, and distance running, led to a dramatic increase in the number of women in the early 2000s being diagnosed with knee osteoarthritis.  This is not to say that women should not participate in sports - in general, all athletes should take care to avoid traumatic injuries as this can commence a cascade of degeneration which is not completely understood.

Osteoarthritis results from a degeneration of fluid inside joints, called synovial fluid, which acts a lubricant for the moving parts of joint, called articulating surfaces.  Synovial fluid plays much the same role in your joints that oil does in a car engine.  When this fluid decreases in quality and quantity, the articular cartilage which covers bones degenerates.  Cartilage does not contain pain receptors, and for this reason protects the bones inside joints.  When cartilage wears away, surfaces of bones – which do contain pain receptors - begin to rub together.  This leads to a wearing away of these surfaces, creating pain and loss of mobility. Some people are more likely to develop osteoarthritis than others.  Risk factors include:

• Being overweight.  Being overweight leads to excessive force on the articular cartilage, specifically of the knee and hip.
• Altered gait.  This leads to asymmetrical loading of joints, which increases the risk of joint degeration.
• Structural factors such as being bow-legged (varus) or knock-kneed (valgus).  This leads to mis-alignment of the knee joint, which can cause arthritis to develop over the course of many years.  Exercises to correct muscular imbalances that occur due to these factors can be highly beneficial.
• Surgery on a joint involved in the exercise program.  The initial injury requiring surgical intervention in the vast majority of cases alters the structural integrity of the joint.  In addition, it used to be common for surgery to be performed on the knee for certain conditions that are best treated conservatively – in these cases, the surgery itself can be a catalyst the ensuing degeneration.
• Discomfort and/or tightness the day following physical activity.  The breakdown of cartilage leads to the release of chemicals that irritate the synovial cells.  This leads to an increased production of synovial fluid that causes tightness, discomfort and sometimes swelling 10-14 hours after the offending activity.  This is called chemical synovitis, and is a main cause of the progression of osteoarthritis.
• Risky exercises.  For example, deep squats put tremendous pressure on the underside the patella (kneecap) and are to be avoided.

Exercise Specialist Recommendations: People with osteoarthritis usually self-limit their physical activity.  This is a mistake, because an appropriately designed exercise program can halt the progression of the condition, as well as restore function and mobility.  Moreover, limiting physical activity leads to the development of secondary problems such as cardiovascular disease, diabetes and hypertension.  Most adults with OA have low aerobic capacity, at least in part owing to this inclination. Studies have demonstrated quite conclusively that a regular exercise program that involves cardiovascular exercise, strength training, and stretching, can create marked improvements in functional capacity, pain, and disability.

• Get professional guidance!  It is critical that an exercise program is designed properly to avoid further joint damage. This can be a physiotherapist, chiropractor, or a medical exercise specialist like myself who has experience treating your specific condition.
• Exercise can hurt when when OA is present - pain when exercising is acceptable, as long as it is not worsened during the exercise session or after.  Follow the 2-hour pain rule - if pain in increased two hours later, the exercise program may need to be adjusted.  If you are stiff and sore the day after - more than usual - this is a sign that chemical synovitis is present.
• Be aware that being physically active can mitigate the deleterious effects of OA - many people with OA are able to function with minimal or zero pain owing to excellent strength and mobility from regular, appropriate exercise.  In fact, 20% of the people with the worst knees on MRI scans actually have no pain at all - revealing that the processes that create pain are not as simple as we once thought.
• Strengthen the lower body.  Restoring strength to the muscles that stabilize the hip and knee will remove pressure by providing stabilization so that the joint can function properly.  Excessive movement within a joint is usually caused directly by weakness in the surrounding muscles.  While the best case scenario is to maintain a high degree of strength through out the lifespan, thus avoiding the excessive movement that wears down joints, benefits can still be had later in the process of degeneration.
• Do an extended warm up.  A long warm up – 10 minutes – of low level cardiovascular activity will ensure joint lubrication and increased elasticity of tissues.
• Split up exercise sessions into smaller segments.  Multiple, shorter sessions per day may reduce joint pain.  As fitness level increases, longer sessions can be incorporated.
• Try swimming or aqua-therapy.  Exercising in the water may be the best option for individuals who cannot tolerate land-based activities.
• Think of the future!  Doing risky exercises may not cause pain now, but may later on.  Deep squats and certain repeated overhead motions can compromise your joints in the future.
• If you are experiencing a great deal of pain and it is interfering with your ability to exercise, consider speaking to your physician to discuss appropriate anti-inflammatory medication.  When used judiciously, non-steroidal anti-inflammatory medications (NSAIDS) can enable you to stay active, and therefore stay strong.  As stronger muscles take the burden off of compromised joints, finding tools to continue to exercise is important, even if the route that has to be taken is pharmacological.  As well, NSAIDS can be taken to manage inflammation that occurs after the exercise session, enabling a person to remain active in the face of joint degeneration. 

The most important advice I can offer is to commit to prevention.  Staying strong and flexible throughout the lifespan results in fewer problems as we age.