Knee Kinesiography

Properly target risk factors to halt knee osteoarthritis

Whether you’re a new fitness enthusiast or a seasoned athlete, most will feel or experience knee pain. The question that should be asked is the following ‘Is this the sign of the beginning of knee osteoarthritis?’

Osteoarthritis is one of the most prevalent and disabling chronic diseases in Canada, and it places a heavy burden on health services. It affects one in ten Canadians. Of these, 40% of osteoarthritis cases are related to the hip or knee joints.

For the knee to work well, the surface of the bones forming the joint is covered with cartilage; an elastic fabric that allows fluid movement between the bones while acting as a shock absorber when the knee must support the weight of the body. Osteoarthritis consists of an irreversible degradation of this cartilage, which then becomes increasingly thin and irregular, which causes progressive friction of the bones against each other. For example, osteoarthritis of the knee can affect the surfaces between the femur and the tibia or between the femur and the patella.

The most common symptoms reported and experienced by patients with knee osteoarthritis are:

  • Knee discomfort following changes in temperature (for example, in the fall or spring when the temperature is particularly wet);
  • Joint stiffness in the morning or after a period of immobility that decreases after a few minutes of movement (usually less than 30 minutes);
  • Crackling/cracking in the knee during flexion;
  • Progressive loss of knee flexibility;
  • Sensitivity to touch or when light pressure is exerted;
  • Pain manifesting during motion when the knee is loaded and relieved by rest;
  • Occasional pain affecting sleep.

There are multiple factors which can cause this “wear and tear” of the cartilage, involving both biological, mechanical and structural factors. Some risk factors are non-modifiable, such as hereditary predisposition (history of osteoarthritis in the family), age (more than 50 years in men and 40 years in women) or the presence of past knee trauma (for example, a meniscal/ ligamentous lesion or a fracture of the femur, tibia, fibula or patella). There are, however, other risk factors that can be used to slow down the progression of the knee osteoarthritis. You can control your symptoms and increase your participation in your daily activities and sports. The factor that are said to be modifiable or influenceable are the following:

  • The alignment of your legs, either in varus (knees facing outwards) or valgus (knees facing inwards). Misalignment increases pressure on specific regions of the knee that are not necessarily able to receive this pressure.
  • The three-dimensional movements performed by your knee during various daily activities (knee biomechanics). Poor biomechanics shifts the loads absorbed by the knee to areas of the cartilage that are more prone to deterioration.
  • Repeated impact on the knees; whether resulting from work or sport.
  • Obesity (Body Mass Index (BMI)> 25, click here to measure your BMI). Excess weight drastically increases the load on your knees.
  • Physical inactivity. This leads to a decrease in muscle tone and a reduction in the supply of blood and oxygen to the cartilage, which promotes muscle stiffness and maintains pain.

So, what about runners? The scientific literature tells us that the knee absorbs between 3 and 8 times the weight of the runner with each impact on the ground. However, although repeated loading on the joint is considered a risk factor for osteoarthritis, there is controversy about the predisposition to develop knee osteoarthritis in runners. In fact, there are almost an equal number of studies arguing each side as to wether or not running increases the incidence of knee osteoarthritis. There is still no scientific evidence to explain why some runners develop osteoarthritis and others do not. One certainty remains, however, that a targeted intervention at the level of the risk factors mentioned above remains the best way to slow the progression of osteoarthritis.

The Arthritis Society of Canada website currently offers a multitude of general information and tips to familiarize yourself with osteoarthritis and the means available to treat it. It can be discussed with your doctor who can guide you to the most appropriate solutions for your situation. Remember, being actively involved in your treatment plan improves the success rate of your interventions.

By : Alexandre Fuentes, Ph. D. – Marc Therien, M. Sc – Dr Robert Pontbriand, M.D. – Degree in Sports Medecine – Nathaly Gaudrault, Ph. D. – University of Sherbrooke – Scholl of Rehabilitation -Faculty of Medecine and Life Sciences

Referneces :Image taken from Mon Partenaire SantéCheng Y, et al. 2000.Spector TD et al. 1996.Chakravarty EF et al. 2008.Sohn RS and Micheli LJ 1985.Kujala UM et al. 1995.