Does being overweight cause osteoarthritis?

Lower back pain is only second to the common cold for missed works days in the United States. Eighty-five percent of people in the industrialized world will have an episode of debilitating back pain in their life. Many of these sufferers have symptoms related to osteoarthritis of the spine. According to the Arthritis Foundation, forty six million people in the United States are affected by osteoarthritis (OA).

The Arthritis Foundation defines OA as:
Osteoarthritis, a degenerative joint disease in which the cartilage that covers the ends of bones in the joint deteriorates, causing pain and loss of movement as bone begins to rub against bone. It is the most prevalent form of arthritis.

The hips, knees and shoulders are also common areas of OA along with the spine. When these joints are painful they will interfere with many exercise programs. Since the hips and knees are load bearing joints for walking, standing, etc., they assume a larger percentage of the impact forces during any upright activity. Reviewing any of the literature on osteoarthritis (OA), you will inevitably see being overweight and obesity commonly listed as “causes” of OA.

From a biomechanical standpoint, I do not believe that excess body weight causes OA. I do believe additional body weight can magnify other mechanical factors leading to OA. If we think about the cartilage as wearing out on the bones, the misconception is that it is the entire bone. Instead it is often an area on the bone that is subject to excessive friction relative to the other parts. I often describe this to my clients as a “hot spot” in the joint. If you apply more pressure to that spot (i.e. more body weight), it will certainly be more sensitive than if less weight were applied. Reducing a person’s body weight does reduce the pressure on the hot spot, but it does not reduce the hot spot itself.

The overweight person often says “I can’t exercise because it hurts”. We say, “It hurts because you don’t exercise”. The caveat here is first defining the type of exercise we are referring to. Far too many people who don’t exercise lump all forms of exercise into one big category. And if you speak to any fitness professional, we can break exercise into multiple categories. These can include but are not limited to:

• Corrective exercise
• Flexibility exercise
• Mobility exercise
• Restorative exercise
• Strength training
• Aerobic conditioning
• Metabolic conditioning
• Sport specific exercise
• Mind/body exercise

For us, proper exercise would refer to a program that first influenced how the body moves. This would incorporate a corrective exercise program that improved joint mechanics to better distribute the forces in the joint. This also does not take away the hot spot but it does reduce the pressure on it and improves the overall function of the joint. This in turn reduces the pain and slows the progression of further degeneration.

Let’s use the knees for example. In our example the person has genu valgum (“knocked knees”). This may in part be congenital. But it is also a result of muscle and soft issue influences on the knee joints. The valgus position of the knee increases the pressure on the outer knee and decreases pressure on the inner knee. Therefore, the forces that should be shared on the inner and outer knee are much greater on the outer knee. This often results in accelerated degeneration to the inner aspect of the knee while the outer aspect remains normal or closer to normal.
valgus knee stress
(Illustration credit: Ajit Chaudhari, PhD, Assistant Professor, Dept. of Orthopaedics Ohio State University)

Common imbalances associated with genu valgum are tightness of the hip ADDuctors and iliotibial band. In addition, the hip ABductors are weak relative to the adductors and do not resist the pull of the femur toward the midline of the body which leads to the valgus position of the knee. In many cases the foot and ankle are involved as well.

Addressing the body’s movement patterns through the muscles and connective tissue you improve the joint mechanics and decrease the stresses that precede and/or perpetuate the degeneration. Both sides of the knee joint now “share” the forces a little more thus removing some pressure from the “hot spot”.

This will allow the overweight individual to get all the other benefits associated with the exercise experience including:

• strength
• increasing energy
• improving sleep
• controlling weight
• decreasing depression
• improving self-esteem.
• combating osteoporosis
• reducing the risk of heart disease

Osteoarthritis is a degenerative process and the result of long term wear and tear. A strategy of ice and medications only douses the fire but never touches the fuel. And as long as you are moving the way you have always moved, the fuel will continue to build up. Changing the way you move through corrective exercises can cut off the fuel line to that fire.

See how Function First’s corrective exercise program can help you by clicking here.

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3 Responses to “Does being overweight cause osteoarthritis?”

  1. Rick Kaselj says:

    Anothony,

    Another great article.

    Excellent point about knocked kneed and the change of force on the internal knee structures.

    Rick Kaselj of ExercisesForInjuries.com

    .

  2. Janelle says:

    Great article. As a physical therapist I see how both excess body weight and limited strength can impact joints.

    For specific treatment recommendations for osteoarthritis, visit:

    http://www.joint-pain-solutions.com/osteoarthritis-treatment.html

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