Expert Panel Question???
“After a run my knee begins to hurt fairly badly. It hurts a little during the run but mainly after. Is there a certain type of shoe that would help with my knees or is the only solution not to run?”
Knee pain is probably the most common injury complaint in runners and has a variety of causes. The most common, Patellofemoral Syndrome, actually also goes by the lay name “Runner’s Knee”. It is more common in women but can occur in men too. It is characterized by pain in the front of the knee, is worse going up and down stairs, during squats or lunges and often results in a deep ache in the knee after a prolonged knee-bent position (such as sitting in a class, movie, car or on a plane). The fact that your knee pain is not so bad during your runs but afterward makes this the most likely problem although it can get bad enough to become an issue during runs too. It is thought to be an injury that occurs to the under surface of the knee cap (the patella) when the knee cap and the bone below it (the femur) are not in alignment.
The under side of the patella has a small ridge running vertically through the middle of it and the femur below has a corresponding groove. These two should remain lined up as the knee bends and straightens. A misalignment between the patella and the femur can be due to genetic factors, biomechanical problems or the result of muscle imbalances. Since we can’t do much to change our genetics, the focus is on the muscle imbalances and biomechanics. As a one directional sport i.e. straight ahead, even elite runners are notorious for developing muscle imbalances.
Running is very good at strengthening the outside muscle of our thigh (lateral rectus) and very bad at developing the inside muscle of our thigh (vastus medialis). The vastus medialis is responsible for the last bit of straightening our leg at the knee (the last 15 degrees of extension) and pulling our patella towards the middle. Alternatively, the lateral rectus is responsible for taking our knee from fully bent to almost straight and pulling our patella towards the outside. Running rarely involves fully straightening the leg so the vastus medialis rarely sees any action during running whereas the lateral rectus becomes quite strong. The stronger lateral rectus wins and pulls our patella to the outside and out of the groove of the femur, rubbing the sensitive underside of the patella on the femur with each stride. The pain from the inflamed and injured underside of the patella may not be noticed during the run but will come to your attention after as the inflammation sets in. In addition to the thigh muscle imbalances, imbalances of the muscles of our hips also play a role in patellofemoral syndrome.
The muscles that bring our leg out to the side and rotate our leg outwards at the hip are often very weak in runners due to the straight-ahead-only nature of running. Biomechanical factors of the foot and ankle can also play a role in patellofemoral syndrome particularly if you pronate (roll your foot in with each step) excessively or are flat footed. In additional to rolling their foot in with each step, pronaters typically rotate their lower leg (tibia) inward also and, since the patella is attached to the tibia, the patella will shift from side to side and out of the femur’s groove with each stride instead of gliding up and down within the groove. An arch support or stability or motion control running shoe can often correct this problem.
If you are diagnosed with patellofemoral syndrome, a visit to a physical therapist would be a good place to start. The physical therapist can assess for any muscles imbalances and suggest strengthening exercises to correct the weaker areas. While continuing the strengthening program (and since strength gains may take a while), some will use a knee brace or taping technique to keep the patella properly aligned thus allowing you to continue running without further injury to the underside of the patella. The physical therapist can also assist with these additions to your program. Your next stop should be a shoe store with staff with an expertise in running shoes. They will be able to pick out the proper shoe for your running style and can give advice on arch supports if needed.
Although there are certainly other causes of knee pain in runners, patellofemoral syndrome is the most common and fortunately rarely requires a visit to the surgeon.
by Steve Scharmann – MD, Sports Medicine, Family Practice | Competitive Runner/Triathlete