I had surgery in October to repair a torn meniscus. The injury was the result of extreme hyperflexing and twisting over a period of years (yoga and rock climbing). Cycling involves a very controled and limited range of motion, no matter how hard you are pedaling, and there should be zero twisting forces on your knee. The doctor had me on the bike for PT within a few weeks of the surgery. Now, almost nine months later, I'm still reluctant to rock climb because I could find myself in a situation where I'm committed to making a move that might "pop" my knee again. Also, I'm pretty sure my other knee has a small tear that could worsen. Consequently, I've been riding my bike a lot, and my knees feel great. As for yoga, there are many poses I will never do again.
I would suggest that your doc is probably correct in saying that you can ride as much and as hard as you like, because, given the range of motion in cycling, the tear isn't likely to get worse. However, I'm assuming that your injury resulted from extreme hyperflexing/twisting as well. I'm not an expert, and perhaps there are other ways to tear the meniscus. But I do know that the hyperflexing/twisting is the most common way to get the injury. That said, if the tear is really bad, then perhaps even the range of motion in cycling (pushing hard on the pedal at the top of the stroke is where the knee would be the most vulnerable) is enough to aggravate the tear. This is a judgement call for you and your doc to make. I would just be as explicit as possible when discussing and asking questions.
The bummer about meniscus tears is that they don't heal on their own. You can only prevent them from getting worse by limiting your range of motion. If intend you do other sports/activities that may aggravate the tear, then you might consider the surgery option sooner rather than later, because the worse the tear gets, the less likely it will be repairable, and in that case the torn section will have to be removed. The loss of this cushion in your knee will make long term arthritis much more likely and possibly limit your activity level later on.
Hope this helps
Last edited by northboundtrain; 06-29-08 at 04:04 PM.