Research on PFPS is ongoing. This condition causes knee pain when the patella (kneecap) doesn't track up and down correctly during knee movement. Foot position is a key factor in this problem. The angle of the knee changes when the arch of the foot is dropped down (flat foot). The same thing happens if the arch of the foot is too high.
Even small changes in foot position can affect the way the muscles contract. The quadriceps (thigh) muscle is a key player in PFPS. If one side of the muscle contracts more than the other, the patella is pulled in that direction. When each part of the quadriceps muscle contracts in balance, the patella stays in the middle.
A recent study at the showed that orthotics can make a difference in muscle activity. Orthotics are shoe inserts that help put the foot in a better position. Treatment to address foot position and muscle activity may help PFPS the most.