The patella (kneecap) is situated in a groove of the femur called the trochlear groove. Throughout walking or running, the patella must be aligned centrally in this groove.
The patella tracks in an upward and downward motion through the groove. Problems and pain result however, when the patella is not tracking vertically in this groove but rather laterally, or sideways.
In this case, two bony surfaces, the trochlear groove and the underneath surface of the patella rub against each other, creating a friction type of pain known as patella femoral pain, or ‘runners knee’.
The knee is by far the most common location for running injuries. Between 30 and 35% of all running injuries occur in the knee.
The most common diagnosis is patella femoral pain, or runner’s knee. Runners describe this type of pain as a diffuse, hard to localise pain around (and often underneath the surface) of the patella or kneecap.
The pain can be sharp or dull, and is most frequently during running.
Various factors can contribute to this problem but most common is subtalor pronation (an unwanted rolling-in motion within the ankle joint.) This source of many running injuries begins at the foot and leads sequentially up the leg. Pronation usually begins at heel strike.
A normal lateral (outside) heel strike contorts to excessive medial or inside roll of the midfoot. As the foot rolls toward the inside, the lower leg, tibia, and fibia also roll inward, thereby forcing the knee and patella to roll medially.
Another possible contributing factor to this problem can be weak vastus medalis muscles (the inner aspect of the quadriceps). These muscles normally hold the patella in a vertical position throughout walking or running.
Treatment will vary depending on the cause. If the symptoms are caused by a muscle imbalance an exercise programme will be prescribed to correct any such imbalances.
If the symptoms are caused by pronation within the subtalor joint, medically prescribed orthotics are used to minimize subtalor pronation, and thereby stop the adverse internal rotation of the leg.
By preventing the knee from rolling medially, the patella is allowed to track vertically, again minimising the patella femoral pain.
Use a prefabricated pronation control orthotic such as the Orthosport Activ-8 orthotic, a perfect choice for moderate over pronators. The orthotic will help reduce rotational forces which are responsible for patella mal-tracking.