Preserving and protecting knee cartilage
Why are some cartilage injuries of the knee easily repairable while others are not? In order to answer that question, we have to start by understanding what type of cartilage lives in the knee.
Preserving and protecting knee cartilage
Why are some cartilage injuries of the knee easily repairable while others are not? In order to answer that question, we have to start by understanding what type of cartilage lives in the knee. There are actually two different cartilage structures in the knee. The first is articular cartilage (the joint surface) and the second is the meniscus (the cushion between the bone.)
Articular cartilage is the slippery structure that covers the ends of bones in all the joints in the body, allowing them to move smoothly. And it’s good at what it does… in fact, articular cartilage is 100 times more slippery than ice sliding over ice!
The meniscus on the other hand is a C-shaped structure in the knee, which acts as a shock absorber. There are actually two menisci in each knee, one on the inner side of the knee and the other on the outer side. The meniscus is not attached to bone like articular cartilage, but rather it sits in the knee between the thigh bone and the shin bone. Whether walking, running, or jumping, the meniscus absorbs and evenly distributes forces throughout knee.
When we tear the meniscus, it can no longer do its job of protecting the surfaces of the knee, which can eventually lead to arthritis. As orthopedic surgeons, we do everything we can to repair or preserve as much of the meniscus as possible.
There is often confusion with regard to injuries to articular cartilage versus the meniscus. In general, when we hear of an athlete having a “tear” of cartilage in the knee, this refers to the meniscus. On the other hand, the terms “cartilage defect” or “arthritis” refer to an injury or degeneration of the articular cartilage.
Most knee arthroscopy in athletes involves tears of the meniscus. A tear of the meniscus can be treated surgically in one of two ways: sewing it back together, or removing the torn portion of the meniscus, known as a meniscectomy.
So why not just repair all of them? Menisci have a poor blood supply and often will not heal. Generally speaking, tears in younger patients in areas with “reasonable” blood supply will heal and can be repaired. Interestingly, repairs require more recovery time than meniscectomies because repairs need time to heal. That is why some athletes undergoing a knee scope for a torn meniscus are back in a few weeks while others are out for months.
I remember receiving a late night call the day prior to a collegiate baseball player’s knee arthroscopy whereupon his father (a medical professional) urged me to ‘trim’ rather than repair the meniscus to get his son back to play quicker. I still see the father and jokingly remind him that I would not have wanted him to be my son’s orthopedic surgeon.
Injuries to the articular cartilage are more complicated and difficult to treat because the body does not heal or re-grow this type cartilage on its own. It is different than a fractured bone or a skin laceration. To further complicate matters, there are many athletes who are living with articular cartilage wear and tear and don’t even know it. A study of knee MRIs in NBA players in 2005 showed 50 percent of players with joint surface abnormalities. These players had no symptoms!
For those who are symptomatic and unresponsive to medications, therapy and injections, there are surgeries aimed at restoring or replacing the injured and missing cartilage. These include procedures like microfracture, cartilage transfer, and cartilage implantation. These surgeries are for small defects in the articular cartilage and do not work for widespread arthritis. Much work is being done in orthopedics to improve the treatment of these injuries to articular cartilage because, despite our best efforts, these surgeries do not always fix the problem. These injuries can often be debilitating or career ending. (e.g. Jeff Ruland, Greg Oden)
So there you have it… everything you need to know about cartilage in the knee! Just remember, it’s like tires on your car—treat them well and don’t wear them out.
-By David Rubenstein, M.D., Lankenau Medical Center
Doc - any suggestions on chondormalcia of the right knee? 33 year old male, rest and PT did not help. I've had a round of orthovisc injections with limited success. I'm unable to run, have trouble going up and down stairs and generally am limited. Seems that surgical options are limited and are mostly ineffective. Any thoughts?— mrbelding- I tore my meniscus while in high school, about six years ago. I ignored the problem for several months, which ended up being a mistake. Got it repaired, as I was young and an athlete. The recovery took months, I couldn't run for close to half a year, but then it was good as new.
Unfortunately, the repair wasn't 100% successful, and I tore it again around a year later. This time, the surgeon trimmed away the offending piece. Recovery was a piece of cake, I could walk and bend my knee immediately after the surgery. They didn't even give me crutches. However, I do still get some pain in my knee during/following vigerous activity. Hopefully it won't continue to get worse, as I'm only 23 years old.— davidj209 - Chondromalacia in my mid-30's... Learned to roller skate (before blades) to strengthen legs. Torn ACL in mid-40's... told I had 'severe' osteoarthritis. Bone spur removed at 50... described as 'bone on bone'. Torn meniscus in mid-50s... informed that I have 'stage 4' osteoarthritis. Still playing full court b'ball (with guys younger than half my age) three times a week. What keeps me going? Glucosamine, Chondroitin, MSM & Hyaluronic Acid supplements... every day. Aspirin before exercise with slow warm ups and some weight training . At 62 I may be (much( slower, but I'm still going strong. 'The Legend'— Red
- "A study of knee MRIs in NBA players in 2005 showed 50 percent of players with joint surface abnormalities." When I read those sorts of statements, I cringe. I once read that only 3% of the population were properly nurishe (eating properly), fit (exercising properly and sufficiently) and rested. That statistic is damning because it means that what we think is "normal" is derived from scientific observation of people with bad habits. The joints of an aging overweight out of shape couch potato will, on average, look different from those of an professional athlete in his prime, regardless of symptomology. Similarly, BMI is not at all helpful. When Muhammed Ali defeated George Foreman in 1976 at 6'2" and 218 lbs he was considered overweight. All male competitive body builders would be considered obese, despite very low percentages of body fat. I don't know whether the NBA players involved showed pathology, but I think normal should be determined based upon a review of the muscles, joints, body weights, metabolisms and muscle to fat ratios of fit and active individuals, not couch potatoes.— jdridd
- I am 60, have arthritis in both knees, cannot run, take cortisone shot once a year, cannot hit with golf clubs except chipping and putting. What are my options? Should I get both knees replaced? Would that be better than my existing knees? How long to recover from total knee replacement? IS it very painful? I would want minimial invasive surgery - would it work for me?— Aces high
- I am 60, have arthritis in both knees, cannot run, take cortisone shot once a year, cannot hit with golf clubs except chipping and putting. What are my options? Should I get both knees replaced? Would that be better than my existing knees? How long to recover from total knee replacement? IS it very painful? I would want minimial invasive surgery - would it work for me?— Aces high
