People suffering from patellofemoral pain syndrome (PFPS) have a lopsided tug of war going on in the muscles around their knee. PFPS develops when there's an imbalance in the strength of muscles that move the patella (kneecap) in its groove as people bend and straighten their leg. The stronger muscle can never quite win the war, but it tugs the patella into an irregular gliding pattern. Like a train that runs off the tracks, the off-track patella still moves, but moves with a grinding friction.
Patients with PFPS can display a variety of symptoms. Usually, they complain of an aching pain in and around the kneecap. The pain tends to worsen after they sit in the same position for a while with their knees flexed, and also after they do physical activities. In the most extreme cases, patients' knees can give out, which usually happens after they walk down a flight of stairs or increase their level of physical activity.
Active people, however, are not the only ones susceptible to the condition. People with poor posture and people with improper foot mechanics are more at risk. Women must also be careful, as their bodies make them more vulnerable to muscle imbalances than men. With a wider pelvis, women generally have one thigh muscle that's stronger than the opposing thigh muscle in the same leg. The stronger muscle, usually the outer thigh muscle called the vastus lateralis (VL), pulls harder on the patella than the weaker one, usually the inner thigh muscle called the vastus medialis (VM) and its end portion known as the vastus medialus obliquus (VMO).
Another potential cause of PFPS is flat feet. If you have flat feet, it can cause your tibia (shinbone) to rotate inward, which places extra pressure on the muscles around the knee and possibly exaggerates muscle imbalances and patella grinding.
Fortunately, studies show that 80% of PFPS sufferers respond well to non-invasive treatment, and healthcare practitioners regularly care for patients with a variety of non-invasive techniques. If your healthcare practitioner has diagnosed you with PFPS, he or she will probably combine these non-invasive techniques with rehabilitative exercises to get the patella back on track.