Patellofemoral pain syndrome
Patellofemoral pain syndrome is a clinical diagnosis of disordered patellar tracking causing poorly localized anterior knee pain with stairs, squatting, and prolonged sitting, requiring no imaging, and its only proven long-term treatment is physical therapy that strengthens the quadriceps, hamstrings, and gluteal muscles.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Patellofemoral pain syndrome (PFPS) is disordered patellar tracking with knee movement that produces poorly localized anterior knee pain, classically localized to or behind the patella, brought on by…
- Epidemiology
A common cause of anterior knee pain in runners, and among the most frequent knee complaints in ambulatory and sports medicine practice.
- Risk factors
Weakness in one or more lower-extremity muscle groups, particularly the quadriceps, which is described as the underlying mechanism responsible for the syndrome.
- Pathophysiology
PFPS is caused by disordered patellar tracking with knee movement: abnormal or asymmetric patellar motion within the femoral trochlear groove during flexion and extension loads the patellofemoral…
- Clinical features
Poorly localized anterior knee pain that can be localized to the patella or behind the patella is the hallmark and defining feature; this is a clinical diagnosis, and the diagnostic criterion is this…
- Differential diagnosis
Iliotibial band syndrome: lateral knee and distal thigh pain with tenderness 2 to 3 cm proximal to the lateral femoral condyle and a positive Noble test, unlike the anterior/peripatellar location and…
- Diagnosis
Patellofemoral pain syndrome is a clinical diagnosis, confirmed by the history of poorly localized anterior/peripatellar knee pain reproduced by activities involving knee flexion (stairs, squatting…
- Management
First, in the acute phase, modify activity and apply cryotherapy (ice or cold-water immersion) to control pain.
- Complications
Chronic or recurrent anterior knee pain from incomplete rehabilitation or premature discontinuation of strengthening exercises, the most common adverse course.
- Prognosis
Most patients improve with a structured physical therapy program targeting quadriceps, hamstring, and gluteal strength, without surgery or injection.
- Prevention
Maintain quadriceps, hamstring, and gluteal strength year-round with structured strengthening exercise performed at least 2 to 3 times per week, not only after symptoms develop, since muscular weakness is the underlying mechanism of PFPS.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Overuse injuries of the knee
Overuse knee injuries, including patellofemoral pain syndrome, iliotibial band syndrome, pes anserine bursitis, and patellar or quadriceps tendinopathy, present with activity-related pain without a traumatic event and are diagnosed clinically by pain location, then managed with activity modification, cryotherapy, NSAIDs, and targeted physical therapy.
- Iliotibial band syndrome
Iliotibial band syndrome is an overuse friction injury of runners and cyclists causing lateral knee and distal thigh pain, diagnosed at the bedside with a positive Noble compression test and treated first with activity modification, ice, and hip abductor strengthening rather than imaging or surgery.
- Osteoarthritis
Osteoarthritis is a chronic progressive joint disorder of cartilage and subchondral bone degradation with low-grade synovitis, diagnosed clinically from age, activity-related pain, and exam findings, and managed with exercise, weight loss, topical or oral NSAIDs, and joint replacement for refractory disease.
- Meniscal tear
Meniscal tear is diagnosed clinically from a twisting-injury history with joint-line tenderness and a positive McMurray or Thessaly test, and management is conservative first for both acute and degenerative tears, with surgery reserved for persistent mechanical symptoms.
- Anterior cruciate ligament tear
Anterior cruciate ligament tear is a noncontact pivoting knee injury diagnosed clinically with the Lachman test and confirmed on MRI, and the central decision is surgical reconstruction versus supervised rehabilitation based on age, activity level, and knee instability.
- Knee trauma
Acute knee trauma spans ligament sprains, meniscal tears, extensor-mechanism injury, and fracture-dislocation, with the anterior cruciate ligament injured most often; the first priority is excluding knee dislocation with popliteal artery injury and compartment syndrome before treating the specific ligamentous or meniscal pattern.