|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.
Bert R. Mandelbaum MD DHL (Hon), Medscape Orthopedics February 19, 2016
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.
|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.
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.
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.
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.
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.
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.
Sometimes patients have already injured their cartilage so badly by the time they come to me that improving their biomechanics won’t fix it.
So the next step is to assess the damage. Using MRI, I grade the articular cartilage defect by diameter and depth, using the Outerbridge Classification for Grading Chondral Lesions of the Knee Arthroscopically or the International Cartilage Repair Society Cartilage Lesion Classification System.
The knee can’t send a text or email; it communicates with pain and swelling. So I ask my patients about these symptoms and about the extent of their disability. I situate these patient-reported outcomes on a scale. If you’re training and competing and your knee swells every 2-3 weeks, it’s very different from “I can’t run at all.”
I also need to know how that disability is affecting the patient’s life. Is this a marathon runner who is competing as part of his or her career? A collegiate athlete? Or a recreational runner?
My mind keeps coming back to the question, How can I return this athlete to sport? Medicine and technology are important, but sports are at the beginning and the end of the work we do with athletes.
In most cases, timing is everything. Recovery from articular cartilage resurfacing surgery usually takes 6-12 months. Sometimes it takes even more time to fully return to sport. So if it’s January and the patient is training for the Los Angeles Marathon in February, I don’t schedule an operation right away. There’s a 100% chance the patient won’t have recovered in time to compete.
Instead, I might try a performance-enhancing adjuvant such as injections of hyaluronic acid, platelet-rich plasma (PRP), stem cells, or some combination. Then the patient might have a 50% chance of being able to compete. The choice of which of these adjuvants can be used may depend on the patient’s insurance coverage and ability to pay for them. I try to stay on top of this quickly evolving field and make sure that I don’t over-promise and underperform.
A lot depends as well on what the patient has already tried that has succeeded or failed. Patients who have tried everything else without success may benefit from surgery. I’ll describe my approach to that in my next column.
Source Medscape Orthopedics
Mandelbaum on Grafts, Biologics, and Rehab in ACL Repair in Medscape Orthopedics