What is it?
Patellofemoral pain syndrome is a term that has often been used to describe knee pain caused by various factors. It involves the patella's ability to properly track between the femoral condyles. Tracking describes how it moves in between the two bony condyles at the end of the femur (think of a train on train tracks). An athlete may experience pain when the patella does not track properly. Improper tracking can be caused by a variety of reasons.

It hurts Where?
The location of pain with PFPS can vary depending on what is contributing to the problem. Generally it produces anterior knee pain. An athlete may complain of pain below the kneecap as well as along the medial and lateral borders (horseshoe pattern around the knee cap). Pain is often increased after activity. Athletes will often experience some pain when walking up and down stairs. They typically will have pain when straightening their leg after prolonged flexion (sitting in class, or driving).

How does it happen?
PFPS is a gradual onset injury that may be caused by a variety of reasons such as:
1) muscle strength imbalance
2) muscle flexibility imbalance
3) structural malalignments.

The group of muscles that attach to the knee cap are the quadriceps, which are made up of 4 muscles. If the strength in these muscles isn't balanced the patella will not track correctly. Patella tracking is also affected by the muscles that cross the hip and attach to the femur (thigh bone). Gluteals and hamstrings assist in externally rotating your femur (try it stand up in front of a mirror and squeeze your butt muscles, you should see your upper thigh externally rotate). This will in turn affect how the patella moves between the femoral condyles. If the gluts are weak the patella could be tracking more laterally than it should because the muscles aren't externally rotating the femur enough to allow the patella to track properly. Improper patellar tracking can lead to pain. Muscle flexibility imbalance can also play a role in PFPS. Your hip flexors (the muscles that allow you to move your thigh forward) attach to your femur as well. They not only flex your hip but one muscle in particular, the psoas muscle, assists with internally rotating your femur. If this muscle is tight the femur will remain slightly internally rotated causing the patella to be displaced lateral to the femoral condyles.

Structoral malalignments not only at the knee but also at the ankle and hip can be a contributing factor to PFPS. These will need to be recognized by a physical therapist, athletic trainer, or physician.

Similar Injuries:
There are a couple of other conditions that can mimic some of the pain associated with PFPS. Osgood Schlater's Disease occurs in mostly young adolescent males that are active and usually undergoing a growth spurt. Their bones are growing faster than the patellar tendon. This may cause part of the new bone growth (cartilage) to tear away from the bone. Pain would be felt primarily below the kneecap. Tendonitis (inflammation of the tendon) and bursitis (inflammation of the bursa) can also cause knee pain. IlioTibial Band syndrome also involves improper tracking but is specific to the ITB.

Treatment:
Initial treatment should emphasize managing pain and inflammation primarily with ice bags and any modalities chosen by the ATC or PT. Rehab should focus on correcting any muscle imbalances both in regards to strength as well as flexibility. If PFPS is being exacerbated due to a malalignments at the ankle then orthotics may be an option. Orthotics would help by placing the foot and ankle in a more proper position.

Participation Status:
This will vary depending on the severity of the condition. In mild cases the athlete will be able to play but may experience discomfort during and especially after playing, a rehabilitation program should be implemented at this stage. As time goes on if the causes are not address pain will often continue to increase to the point in which it will be very painful for the athlete to go down stairs and do other daily activities that involve knee flexion. At this point the athlete's ability to perform would be severely affected. A well organized rehabilitation program will normally have very good success with this knee injury.