Patellofemoral pain, also called PF pain, is the name for pain in the front of the knee around the patella (the kneecap). It is a common disorder. PF pain is especially common in adolescents and young adults. Many athletes suffer from PF pain, and more women have it than men. However, the condition is not well understood. Doctors think that many factors may be involved in PF pain. Weak muscles around the knee, an off-center patella, and a flattened arch (foot pronation) may all contribute to PF pain.
Weak hip muscles may also help cause PF pain. These authors tested that theory. They checked hip strength in 15 adolescent girls and young women who had PF pain. They compared the results to 15 girls and young women with healthy knees. All subjects took part in sports. Hip strength was tested while lying on the side (hip abduction) and while sitting (external rotation).
Results showed that subjects with PF pain had much lower hip strength than subjects who had healthy knees. Subjects with PF pain were 26 percent weaker in hip abduction and 36 percent weaker in external rotation. The authors feel the weak hips were related to PF pain in these young women. Weak hips can allow the kneecap to move out of alignment during exercise. Over time, PF pain develops.
The authors recommend training programs to strengthen the hips for patients with PF pain. They note that this study has one major limitation: they can't tell which came first, the PF pain or the hip weakness. It could be that the hip muscles became weak because the women were protecting a painful knee. No matter which came first, other studies have shown that exercises to strengthen hip muscles can help get rid of PF pain.
Mary Lloyd Ireland, MD, et al. Hip Strength in Females with and without Patellofemoral Pain. In Journal of Orthopaedic & Sports Physical Therapy. Nov. 2003. Vol. 33. No. 11. Pp. 671-676.'