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For Articular Cartilage Injury, a Holistic Approach Is Best

Bert R. Mandelbaum, MD, DHL (Hon)


February 19, 2016

A Surgeon's Holistic Approach

After years of treating knee injuries, I've come to a realization about articular cartilage: You've got to understand the whole knee. It's not enough to master arthroscopy. You must also understand the knee as an organ, its biomechanics, its extracellular matrix, and its molecular structure. This holistic understanding gives you multiple opportunities to make a more accurate diagnosis and develop the most effective treatment.

Let's start with biomechanics. I often find that I can treat cartilage injuries by addressing the way the patient moves. First, I look at dose, frequency, and adaptation to exercise in light of endocrinologist Hans Selye's general adaptation syndrome, a theory of stress that held: Too little or too much is not optimal.[1]

The Right Amount of Exercise

The human body evolved for pursuit of hunting. Our ancestors didn't catch their prey by sprinting. Animals like deer and antelope can run fast for a short time. Human beings can run slowly for a long time. Our ancestors could keep up a slow jog for many miles without stopping and had the intelligence for tracking. They just kept going until their prey dropped from exhaustion.[2]

Having evolved for the physical demands of hunting, our knees work best when we do a lot of walking or running at a clip of 10-15 minutes per mile. The knee joint gets stronger with that kind of exercise. Chondrocytes just love load-bearing, oscillatory forces, which stimulate them to produce glycosaminoglycans. These glycoproteins make up part of the normal fiber and structure of the joint in general, and specifically give cartilage its resilience and pliability.[3]

Too much exercise can have the opposite effect. People who increase their regimens too much or too suddenly can exceed the rate at which their connective tissue can recover from the wear and tear.

Orthopedist Ilkka Kiviranta, MD, PhD, of the University of Helsinki in Finland, put dogs on a treadmill and made them run up to 40 km per day. In the dogs' lateral condyles, the deformation rate of cartilage increased by 16% compared with that of dogs that lived in cages.[4]

So I urge my patients to stay in a healthy exercise zone. I recommend cyclical progression: Every increase of two tenths of a mile is followed by a decrease of one tenth in the next run. So if you start running 3.0 miles, do 2.9 the next time. Then 3.1, then 3.0, then 3.2, then 3.1, then 3.3, and so on.

Risk Factors for Injury

That kind of progression becomes more important with age. In young people, the cartilage is amazingly pliable and adaptable. In older people, it's more brittle and the balance of hormones is less favorable. Menopause and eating disorders can also weaken cartilage.[5]

The risk of injury increases dramatically if there is any instability or misalignment. An abnormal gait can dramatically increase the forces on the cartilage.[6]

And many athletes are totally unaware that they have these problems. Some of them don't even seem to know they have knees until they start hurting. So I talk to them about what the joint is designed to perform.

When you've got a cartilage injury, the first intervention I consider is time; sometimes rest alone will take care of the problem. Then I talk to them about nutrition. For example, I may recommend glucosamine and chondroitin sulfate supplements. In someone who is overweight, I emphasize the importance of weight loss because obesity is associated with progressive breakdown of cartilage and arthritis.[7]

In designing a program that helps people return to sports, I favor comprehensive cross-training. I look at the possibility of training with altered weightbearing using an antigravity treadmill, a bicycle, swimming, or an elliptical trainer. I often prescribe exercises for the upper body and the core, as well as exercises that build neuromuscular control and strength.

But treatments may also include a reduced training schedule, correction of hyperpronation, or advising patients to replace worn-out shoes that are no longer capable of absorbing forces.


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