Patellofemoral pain syndrome | |
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Other names | Patellar overload syndrome, runner's knee,[1] retropatellar pain syndrome[1] |
Diagram of the bones of the lower extremity. Rough distribution of areas affected by PFPS highlighted in red: patella and distal femur. | |
Specialty | Orthopedics, sports medicine |
Symptoms | Pain in the front of the knee[1] |
Usual onset | Gradual[2] |
Causes | Unclear[1] |
Risk factors | Trauma, increased training, weak quadriceps muscle[1] |
Diagnostic method | Based on symptoms and examination[3] |
Differential diagnosis | Patellar tendinopathy, infrapatellar bursitis, infrapatellar fat pad syndrome, chondromalacia patellae[2] |
Treatment | Rest, physical therapy[3] |
Prognosis | May last for years[3] |
Frequency | Relatively common[2] |
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.[4] The pain is generally in the front of the knee and comes on gradually.[2][4] Pain may worsen with sitting down with a bent knee for long periods of time, excessive use, or climbing and descending stairs.[1][5]
While the exact cause is unclear, it is believed to be due to overuse.[1][2] Risk factors include trauma, increased training, and a weak quadriceps muscle.[1] It is particularly common among runners.[3] The diagnosis is generally based on the symptoms and examination.[3] If pushing the kneecap into the femur increases the pain, the diagnosis is more likely.[1][3]
Treatment typically involves rest and rehabilitation with a physical therapist.[6] Runners may need to switch to activities such as cycling or swimming.[3] Insoles may help some people.[3] Symptoms may last for years despite treatment.[3] Patellofemoral pain syndrome is the most common cause of knee pain, affecting more than 20% of young adults.[1][2] It occurs about 2.5 times more often in females than males.[2]