Having seen last time that runner’s knee (a.k.a. chondromalacia patella) is most often the result of poor alignment and/or tracking of the kneecap in the femoral groove, it is only logical that we would next want to know why this happens, since therein lies the cure.
Oftentimes, improper movements of the patella can be attributed to faulty mechanics above or below the knee itself, i.e., the hip or foot. Usually, this involves excessive rotation motions at these joints which is then transferred through the knee, causing a malalignment and tracking motion of the patella. If this is the case, the solution usually lies in correcting this biomechanical fault, such as through exercise for muscle imbalances or, in some cases as we’ve seen before, by use of foot orthotics. When the problem is more specific to the knee itself, however, we must look more closely at the position of the patella in relation to the femur to find the cause.
Movement of the patella is primarily vertical and is controlled by the quadriceps muscle group. Most of us probably think of our “quads” as one muscle, but as the name indicates, it is really four separate muscles in the front of the thigh which attach to the patella. Because the four muscles attach to different areas of the patella, we can visualize these as strings on a puppet. This simplification makes it easy to understand how the patella can move improperly if one of the “strings” is weak and is overpowered by the others, causing the kneecap to move too far to one side as it glides vertically, which in turn causes too much pressure on one area of the patellar surface. Most often, it is the muscle on the inside part of the thigh that is dysfunctional. Traditionally, therapists would instruct exercises to strengthen that particular muscle, but too frequently this was unsuccessful. The problem in many cases was that patients could not do these exercises without causing more pain. It seems that the pattern of unbalanced quads was so well established that the weak muscle couldn’t be fired above the others.
Recently, a therapist from Australia developed a promising technique which allows the muscle to be exercised without causing pain to the patella. This involves evaluating the position of the patella and then correcting any malalignment by strapping the patella with an adhesive tape to help it glide properly in the groove. With the aid of biofeedback or electrical muscle stimulation, the weak muscle can then be selectively retrained to function appropriately. Once this is accomplished, the taping is no longer needed to maintain proper alignment and tracking.
While this treatment is fairly new, the clinical results have been very promising, with excellent recoveries in a short period of time. Of course, not every case has such an easy and happy ending, and when conservative measures such as those described fail, realignment of the patella must then be achieved through orthopedic surgery.
