Patellofemoral pain syndrome

Patellofemoral pain syndrome
Other namesPatellar overload syndrome, runner's knee, retropatellar pain syndrome
Diagram of the bones of the lower extremity. Rough distribution of areas affected by PFPS highlighted in red: patella and distal femur.
SpecialtyOrthopedics, sports medicine
SymptomsPain in the front of the knee
Usual onsetGradual
CausesUnclear
Risk factorsTrauma, increased training, weak quadriceps muscle
Diagnostic methodBased on symptoms and examination
Differential diagnosisPatellar tendinopathy, infrapatellar bursitis, infrapatellar fat pad syndrome, chondromalacia patellae
TreatmentRest, physical therapy
PrognosisMay last for years
FrequencyRelatively common

Patellofemoral pain syndrome (PFPS; not to be confused with jumper's knee) is knee pain as a result of problems between the kneecap and the femur. The pain is generally in the front of the knee and comes on gradually. Pain may worsen with sitting down with a bent knee for long periods of time, excessive use, or climbing and descending stairs.

While the exact cause is unclear, it is believed to be due to overuse. Risk factors include trauma, increased training, and a weak quadriceps muscle. It is particularly common among runners. The diagnosis is generally based on the symptoms and examination. If pushing the kneecap into the femur increases the pain, the diagnosis is more likely.

Treatment typically involves rest and rehabilitation with a physical therapist. Runners may need to switch to activities such as cycling or swimming. Insoles may help some people. Symptoms may last for years despite treatment. Patellofemoral pain syndrome is the most common cause of knee pain, affecting more than 20% of young adults. It occurs about 2.5 times more often in females than males.