If you are having difficulty with your knees, especially going down stairs, squatting, or after sitting for long periods, you may have patellar tracking dysfunction.
Patellar tracking dysfunction or Patella Femoral Syndrome (PFS), in simple terms, refers to an abnormal movement of the kneecap during activity. As we straighten and bend our knee, the kneecap glides up and down in a “groove”. Ideally the kneecap is centered in the groove as it glides up and down, without straying to either side. With Patellar tracking dysfunction, the kneecap tracks to the outside of the groove, (similar to a bobsled banking off the sides during a corner) this creates extra contact on the underside of the kneecap resulting in pain and irritation. Continued irritation will eventually lead to softening of the cartilage on the underside of the kneecap.
Mal (or improper) tracking of the kneecap can be caused by structural abnormality or by muscle imbalances around the knee. Both can alter the position of the kneecap and it’s tracking in the groove.
Structural abnormalities include mal alignment through the upper and lower leg, smaller high resting kneecap, and increased foot pronation (rolling inwards of the foot). Although these structural changes usually cannot be corrected, a specific knee brace, orthotics and proper footwear are often helpful to minimize the irritation on the underside of the kneecap.
Muscle imbalance can result from structural differences in the knee and lower leg but they can often arise after injury, immobilization, prolonged activity or inactivity and repetitive compressive stresses to the knee (stairs, squatting).
Having tight muscles on the outside of the upper leg and knee (primarily the IT Band) can result in the kneecap being pulled to that side of the groove as it is tracking.
One of the most important factors necessary to assure normal function of the kneecap is to have good strength in a muscle that is in the inner side of your knee. It is called the vastus medialis obliquus or VMO. The VMO is responsible for controlling the tracking of the kneecap in its groove as it glides up and down with bending and straightening. Often the VMO will “shut down” after injury, or periods of immobilization or inactivity. Despite the VMO not functioning properly, you will still be able to perform all activities, and sports; you will just be more prone for eventual irritation from the improper tracking of the kneecap.
Management of these muscle imbalances involves reducing the irritating activity or the activities that involve high compressive loads to the knee (stairs, prolonged sitting and squatting). Strengthening the VMO to allow it to control the kneecap optimally and stretching the muscles around the knee so they won’t pull improperly on the kneecap will also help. During strengthening, I often place a muscle stimulator over the VMO muscle (to get a full contraction) and have the individual perform functional strengthening exercises that isolate VMO activity. Taping techniques can also be used to redirect the kneecap to allow it to track properly in its groove.
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