But the cause of the problem still remains a mystery of sorts. We know that an increased Q-angle is part of the problem. You've probably had someone measure your Q-angle and possibly tell you it is increased from normal.

The angle is a measure of the alignment between the femur (thigh) and tibia (lower leg). A line is drawn from the anterior superior iliac spine (ASIS) to the middle of your patella. The ASIS is the sharp pelvic bone you can feel in front of your body. When you put your hands on your hips, the ASIS is usually right under your index finger.

A second line is drawn from the patella's midpoint to the tibial tubercle. The tibial tubercle is the bony bump just below your patella. The angle that's formed by these two measurements is the Q-angle.

An increased Q-angle means the patella is being pulled laterally (away from the other leg). This alters the way the patella tracks up and down over the femur. The result is increased stress on the patellofemoral joint.

One way to combat this problem is to strengthen the quadriceps muscle. The focus of strengthening is on the medial (inner) portion of this muscle. This may be able to help overcome or balance the lateral pull on the patella. Taping and bracing often help as well.

A well-rounded rehab program also includes strengthening of the hip muscles. You should be tested to find areas of weakness and target those muscles in particular. A physical therapist or athletic trainer can help you with this.