Patellofemoral Pain Syndrome (PFPS)



  • Pain in or around the patella that is aggravated with increased patellar loading (e.g., prolonged sitting, squatting, kneeling, or ascending/descending stairs); not attributable to other causes
  • Synonyms: anterior knee or retropatellar pain syndrome, chondromalacia patellae, runner’s knee
  • System(s) affected: musculoskeletal



  • Incidence between 2007 and 2011 in the United States was ~6%.
    • 55% of patients were female.
    • More cases were identified in the southern portion of the United States, compared to other regions of the country (1).
  • In a military population, prevalence of 12% in males and 15% in females (2).

Etiology and Pathophysiology

Increased patellofemoral joint loading, which is often multifactorial (3):

  • Patellar malalignment or maltracking (3)
  • Abnormal anatomy (e.g., patella alta, trochlear dysplasia) (3)
  • Quadriceps asymmetry, weakness and/or tightness (3)
  • Hamstring tightness (3)
  • Laxity of the patellofemoral joint or a tight lateral retinaculum (3)
  • Increased hip joint internal rotation (3)
  • Altered tibiofemoral joint mechanics (3)

Risk Factors

  • Activities such as running, squatting, and climbing up and down stairs
  • Sudden increase in activities
  • Female gender
  • Dynamic valgus
  • Patellar instability
  • Quadriceps weakness
  • Foot abnormalities (e.g., pes pronatus, rearfoot eversion) (1)
  • In adolescents: increased hip adduction strength, although this may represent increased activity level
  • Factors of uncertain significance: age, height, weight, body mass index, body fat, Q angle, and hip weakness

General Prevention

Strengthening and stretching exercises, particularly hip abductors and terminal extension of the quadriceps

Commonly Associated Conditions

  • Overuse injury
  • Knee ligament injury/surgery
  • Patellar tendinopathy
  • Prolonged synovitis
  • Iliotibial band friction syndrome

There's more to see -- the rest of this topic is available only to subscribers.