The Cooper Institute

Founded in 1970 by the "Father of Aerobics"
Kenneth H. Cooper MD, MPH


Knee Pain: Patellofemoral Pain Syndrome

Posted in
Fit Tips

Thursday, Jan 18, 2018

While a vast majority of knee problems involve ligament damage, another common cause of knee pain is patellofemoral pain syndrome (PFPS). PFPS is characterized by pain underneath the patella (knee cap). The pain increases with squatting movements, stair climbing, and prolonged sitting. If the patella is positioned properly, it should glide between the femoral condyles which hold it in place. The knee cap is anchored by the quadriceps tendon (above the knee) and the quadriceps ligament (below the knee). If the patella does not track properly, it places stress on the femoral condyles ultimately leading to knee pain and a grinding sensation during knee flexion/extension. Proper tracking of the patella is dependent on the following factors: the Q angle, depth of the groove in which the patella sits, and the strength of the quadriceps muscles. The Q angle refers to the relationship between the hip and the knee which determines the angle of pull of the quadriceps tendon on the patella. Typically, the Q angle is greater in females than males due to the wider pelvis in females. Therefore, it is no surprise that PFPS is more common in females than males. Long-term problems with PFPS may lead to osteoarthritis of the knee joint. 

Risk Factors:

No one single biomechanical problem has been identified as the cause of PFPS. Therefore, it is likely that multiple issues contribute to its development. Currently, the following have been identified as factors that may contribute to the development of PFPS (Lankhorst, 2012):
  • Weak quadriceps muscles (most evidence for this risk factor)
  • Overload/overuse of the knee in sports and occupational activities
  • Flat feet and foot pronation (causes internal rotation of the hip/knee)
  • High arches (less shock absorption)
  • Weak hip abductors
  • Tight IT band
  • Poor hamstring/quadriceps/calf  flexibility
  • Late onset of vastus medialis obliquus (VMO) activity relative to vastus lateralis (VL)
  • Overweight/obesity
  • Congenital alignment abnormalities (i.e. leg length discrepancy, etc.)

Forward Step-Ups:
  • In a standing position, face a bench or box that is ~12 inches high (can range 6 15 in depending on fitness level). Externally rotate the right hip 30-45 degrees with feet shoulder width apart.
  • Step forward onto the box with the right leg, maintaining external rotation at the hip. Keep the knee from moving forward of the ankle.
  • The hip/knee of the trailing leg should be flexed at a 90 degree angle with the ankle dorsiflexed.
40 Degree Knee Flexion Squats:
  • With feet shoulder width apart, stand with the hips externally rotated 30 degrees with the feet at 10 and 2 o’clock position.
  • Lower the hips into the squat by flexing the knees no more than 3045 degrees (1/3 to 1/2 squats compared to the 90 degrees for a full squat).
  • Keep the knees over the ankles so the knees do not roll inward, and keep the torso upright.
  • To amplify, place a barbell or weighted stick across the back of the shoulders.
Monster Walks:
  • Place a circle band around the ankles and assume a 45 degree bend at the hips.
  • Maintaining a 45 degree bend in the hips and knees, take a large and wide step while keeping the feet pointed forward.
  • Follow with the opposite food, by taking a large step as shown in the video.
  • Perform 8 – 10 steps forward and the perform 8 – 10 steps backwards.
Hip Adduction with Band
  • In an upright position, place a band above the ankle of one leg. Anchor the band away from the body on the same side of the body in a horizontal position.
  • Stabilize the body over the opposite leg, aligning the hip over the knee with soft flexion.
  • Adduct the hip while maintaining the read position and alignment as described above.
The corrective exercises shown in this video aim to strengthen the quadriceps muscle group (specifically the VMO muscle) and increase hip stability. If you are at risk for developing PFPS, some prevention strategies include: gradual increase in intensity/overload, alternate between impact and nonimpact activities, and utilize supportive footwear.

Lankhorst, N.E., Bierma-Zeinstra, S.M., van Middelkoop, M., (2012). Risk factors for patellofemoral pain syndrome: a systematic review. The Journal of Orthopaedic and Sports Physical Therapy, 42, 81 – 94.