Hello. I m Dr. Christensen. I m sorry you re having problems with your knee. I have to agree that you probably sustained an injury during that race a few years ago. Without an examination it isn t possible to give you a specific diagnosis, but there are several possibilities. Meniscal injuries are fairly common in runners and other athletes. Menisci are C-shaped bushings that help protect the large articular cartilage of your knee from compressive and shearing forces. Each knee possesses two menisci, which are vulnerable to tearing and fraying in individuals who put a lot of stress on their knees. The classic signs and symptoms of meniscal injuries include progressive pain, intermittent swelling, clicking and a sensation of locking or giving away. Significant meniscal injuries often require surgery, which can usually be accomplished through an arthroscope. If your original injury involved twisting of your knee while it was bent and you were moving forward, you may have injured your anterior cruciate ligament, which is an internal ligament that lends stability to your knee during forward motion and turning. If the ACL is disrupted, it could destabilize your knee and lead to degenerative changes in the joint (i.e., arthritis), which could manifest as swelling, pain and grinding. Repair of ACL injuries sometimes requires open knee surgery. You might also have a loose body -- a fragment of cartilage or bone -- that was pulled free from a joint surface when you injured your knee. Such a loose body would create wear within the joint and could eventually account for the symptoms you ve mentioned. Any significant swelling or inflammation around the knee could conceivably involve the nerves that pass by the joint, such as the peroneal nerve, and lead to transient numbness in the lower leg. At this point, it sounds like you need the services of an orthopedic surgeon. However, most primary care physicians can perform a knee examination and narrow down the list of possible causes for your symptoms before you see an orthopedist. In addition, your doctor can send you for a MRI, which is the definitive study for identifying abnormalities within the knee. Once a MRI is done, you and your doctor should have a pretty clear idea about what needs to be done to alleviate your discomfort. Until you have a treatment plan in hand, you should ice and elevate your knee when it swells or gets painful, and I d suggest an over-the-counter anti-inflammatory agent, such as ibuprofen or naproxen. I hope that all helps, and I hope you have some answers soon!