by Dennis P. Devito, M.D.
Question: I’ve heard varying opinions on whether it’s possible to actually regenerate
knee cartilage. I’m a 55-year-old male, I have osteoarthritis in my knees, and after a crash last year that resulted in a broken shoulder blade, and a subsequent illness, I lost a lot of weight and a lot of muscle mass in my legs (and elsewhere) due to muscle wasting, basically wiping out all of the leg muscle that I’d built up in 4 plus years of riding. I’ve been trying to rebuild, but progress has been slow, and I’ve been having problems with knee pain, which has limited the intensity and length of my workout rides. I take regular supplements to support healthy joints, and this is helping to reduce pain and lubricate the joints. I’d like to know if it’s possible to regenerate lost cartilage, and how that might be achieved. (I’ve heard claims that glucosamine and condroitin can do this.) — Steve S.
Dr. Dennis Devito Responds: First of all Steve, you are to be commended for your tenacity and desire to recover from what sounds like a bad accident. You are also correct in your approach that building baseline muscle strength will be paramount to supporting your knees, and your other joints as well, since early muscle fatigue merely translates into more stress to the bones and joints. Therefore, some time in the gym will be essential, and should start with low weight/high reps with short rest intervals for 6 weeks, followed by a more standard strengthening program for another 6 weeks, naturally avoiding anything that aggravates knee pain.
To answer your specific question about regenerating joint cartilage would entail an entire orthopedic seminar as this is perhaps the most active area of research and development right now in sports medicine. The reason is that partial thickness injuries or “gouges” in joint cartilage that don’t go down to bone have no real capacity to heal, so they remain as defects. That’s not a problem if they are small and not too deep. Cartilage injuries that go down to bone will bleed, and the body responds by making fibrocartilage, which fills the defect, but unfortunately is inferior to real hyaline (joint) cartilage and breaks down over time.
In general, motion is better for a damaged joint than restriction — the ranging of the knee helps the joint fluid lubricate and nourish the cartilage (cartilage has no blood supply, so it gets its nutrition from the synovial fluid). Cycling is a great way to regain cardiovascular fitness, lower body strength, and not produce too much wear on the damaged cartilage — less shear forces on the joint surface as compared to, say, playing tennis or running. Non-steroidal anti-inflammatory medicines are designed to prevent too much adverse fluid buildup in the joint and help reduce synovitis (inflammation of the joint lining), but do not provide reparative measures. Chondroitin/glucosamine mixes are more helpful for some people and can be very effective with reduction in knee pain, but again do not ‘grow’ new cartilage.
The essential issue is the size and location of your cartilage damage — if it is ‘bone on bone’ (osteoarthritis) then another course of action may be necessary. This diagnosis is made by routine x-rays of your knee, and then possibly an MRI study. You would have to seek out advice from a sports medicine orthopedist well-versed in cartilage issues to see how to proceed after that. This could include anything from drilling the bone to make some fibrocartilage, local cartilage-bone plug transfer, cultured cartilage cell transplantation, to mesenchymal stem cell injection.
For the time being, remember the basics of seat height and position, and pedal position for proper force on the knee, alignment of the cleat (comfortable amount of float), not too much overuse (spin in the small ring), control body weight, and continue muscle strengthening. (There are numerous eArticles and eBooks in RBR’s eBookstore that provide guidance on proper bike setup.)
Dennis P. Devito, M.D., is an orthopedic surgeon at Children’s Orthopedics of Atlanta and is an avid road cyclist. His practice is focused on children and young athletes, especially those with spinal conditions. An avid cyclist from a running background, he spent 15 years intensely competing as an amateur triathlete and was a multi-time member of the USA World Long Course Triathlon Team.