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,
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.
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.
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.