> Table of Contents > Patellofemoral Pain Syndrome
Patellofemoral Pain Syndrome
Rathna Nuti, MD
Robert J. Dimeff, MD
image BASICS
DESCRIPTION
  • Pain in or around the patella that increases after prolonged sitting, squatting, kneeling, and stair climbing (1)
  • System(s) affected: musculoskeletal
EPIDEMIOLOGY
Prevalence
  • Most frequently diagnosed condition in patients <50 years old with knee complaints (1)
  • Women have higher incidence than men (1,2).
  • More predominant in female adolescents and physically active young adults (3)
  • High incidence in physically active populations (3)
  • Incidence of 15-25% in the general population (3)
  • Accounts for 25% of all knee injuries (4)
ETIOLOGY AND PATHOPHYSIOLOGY
  • Multifactorial etiology (1)
  • Direct relationship with hip weakness and poor functional control of the femur during weight-bearing tasks (5)
  • Structural anomalies and lower extremity malalignment also contribute (1).
  • Shortened quadriceps results in increased contact time and force between the retropatellar cartilage and the trochlear groove (4).
Genetics
Unknown
RISK FACTORS
  • Weak quadriceps (1)
  • Female gender;
  • Q angle >20 degrees (1)
  • Limited quadriceps and gastrocnemius flexibility (6)
  • Excessive knee valgus during landing (6)
  • Subtalar hyperpronation (6)
  • Tight iliotibial band and/or lateral retinaculum (6)
  • Decreased strength (or timing) of (between) the medial quadriceps and the gluteus medius (6)
  • Decreased hamstring flexibility (5)
  • Decreased explosive strength (5)
  • Improper training equipment (5)
  • Decreased trochlear groove depth (5)
  • Increased medial patellar mobility (5)
  • Patella alta (5)
  • Increased medial tibial intercondylar distance (5)
GENERAL PREVENTION
  • Mitigate risk factors (1)
  • Strengthening exercises (1)
  • Reduce training volume (7)
COMMONLY ASSOCIATED CONDITIONS
  • Overuse
  • Knee ligament injury/surgery
  • Patellar tendinopathy
  • Prolonged synovitis
  • Iliotibial band friction syndrome
image DIAGNOSIS
PHYSICAL EXAM
  • Patellar tilt test: With patient supine, grasp patella between thumb and forefinger and try to lift up the outside edge of the patella using the thumb (3)[A].
  • Squatting (3)[A]
  • Vastus medialis coordination test: While patient is laying down supine, place fist under patient's knee and ask the patient to extend the knee slowly without pressing down or lifting away from you (3)[A].
  • Apprehension sign: Compress the patella against the femur and ask the patient to contract quadriceps muscles; pain upon contraction is consistent with patellofemoral pain syndrome, although pain may be present in normal individuals as well (3)[A].
  • Compression test: reproduction of pain with compression of patella against the trochlea (3)[A]
DIFFERENTIAL DIAGNOSIS
  • Prepatellar bursitis; patellar and quadriceps tendinitis/tendinopathy
  • Patellofemoral arthrosis; patellar subluxation and dislocation
  • ACL, PCL, and meniscal pathology
  • Soft tissue and bony tumors
  • Iliotibial band syndrome
  • Plica syndrome
  • Patellar fat pad inflammation; patellofemoral osteoarthritis
  • Chondromalacia patella/osteochondral defect
  • Sinding-Larsen-Johansson syndrome
  • Osgood-Schlatter disease
  • Referred pain from hip or spine
  • Traction apophysitis
DIAGNOSTIC TESTS & INTERPRETATION
  • None indicated. In general, imaging is unnecessary and not helpful in diagnosing patellofemoral pain syndrome. If imaging is indicated because of severity, atypical symptoms, or persistence of symptoms despite treatment, four views (plain films) of the knee are recommended to view patellar tilt:
    • Lateral
    • Merchant (also called sunrise)
    • Standing anteroposterior
    • Posteroanterior tunnel views:
  • Radiographic findings may not correlate with symptoms.
Follow-Up Tests & Special Considerations
Radiographic images may be normal until late stages, when the posterior patellar surface becomes irregular and cartilage erosion becomes radiographically detectable.
Test Interpretation
Generally a clinical diagnosis. Tests not necessary.
P.771

image TREATMENT
Conservative therapy is the gold standard (5)[A].
GENERAL MEASURES
  • Stretching and strengthening exercises, especially hip strengthening (5)[A]
  • Taping and bracing (5)[A]
  • Activity modification (5)[A]
  • Cast immobilization (5)[A]
  • NSAIDs for pain management (5)[A]
  • Neuromuscular retraining interventions (especially with physical therapy) (5)[A]
  • Supervised exercise therapy program including quadriceps training (1)[A]
  • Foot orthoses (8)[A]
  • Electrotherapy and biofeedback (8)[A]
MEDICATION
  • NSAIDs for pain management (5)[A]
  • The evidence for beneficial effects of glucosamine and chondroitin supplementation is conflicting and merits further investigation. They may have anti-inflammatory effects and function as articular cartilage and synovial fluid precursors.
  • Nandrolone may be effective, but it is too controversial to recommend for treatment.
ISSUES FOR REFERRAL
Referral for surgery is a last resort after all conservative measures fail. Surgery is rarely needed.
ADDITIONAL THERAPIES
Ice packs after activity improve clinical symptoms.
SURGERY/OTHER PROCEDURES
  • No additional benefits of surgery compared to conservative treatment (8)[A].
  • Attempts to correct maltracking of the patellofemoral joint with a lateral retinacular release or tibial tubercle transposition have shown variable results (5)[A].
  • Rarely indicated
image ONGOING CARE
PATIENT EDUCATION
Patient education and exercises: http://familydoctor.org/online/famdocen/home/healthy/physical/injuries/479.html
PROGNOSIS
  • Patellofemoral pain syndrome often improves spontaneously with relative rest and physical therapy.
  • Conversely, established chondromalacia patella, which involves actual injury to the patellofemoral joint cartilage has a poorer prognosis.
REFERENCES
1. Lankhorst NE, Bierma-Zeinstra SM, van Middelkoop M. Risk factors for patellofemoral pain syndrome: a systematic review. J Orthop Sports Phys Ther. 2012;42(2):81-94.
2. Lankhorst NE, Bierma-Zeinstra SM, van Middelkoop M. Factors associated with patellofemoral pain syndrome: a systematic review. Br J Sports Med. 2013;47(4):193-206.
3. Nunes GS, Stapait EL, Kirsten MH, et al. Clinical test for diagnosis of patellofemoral pain syndrome: systematic review with meta-analysis. Phys Ther Sport. 2013;14(1):54-59.
4. Barton CJ, Lack S, Malliaras P, et al. Gluteal muscle activity and patellofemoral pain syndrome: a systematic review. Br J Sports Med. 2013;47(4): 207-214.
5. Carry PM, Kanai S, Miller NH, et al. Adolescent patellofemoral pain: a review of evidence for the role of lower extremity biomechanics and core instability. Orthopedics. 2010;33(7):498-507.
6. Pappas E, Wong-Tom WM. Prospective predictors of patellofemoral pain syndrome: a systemic review with meta-analysis. Sports Health. 2012;4(2): 115-120.
7. Tenforde AS, Sayres LC, McCurdy ML, et al. Overuse injuries in high school runners: lifetime prevalence and prevention strategies. PM R. 2011;3(2): 125-131.
8. Peters JS, Tyson NL. Proximal exercises are effective in treating patellofemoral pain syndrome: a systematic review. Int J Sports Phys Ther. 2013;8(5): 689-700.
Additional Reading
&NA;
  • Callaghan MJ, Selfe J. Patellar taping for patellofemoral pain syndrome in adults. Cochrane Database Syst Rev. 2012;(4):CD006717.
  • Collado H, Fredericson M. Patellofemoral pain syndrome. Clin Sports Med. 2010;29(3):379-398.
  • Dixit S, DiFiori JP, Burton M, et al. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75(2):194-202.
  • Fredericson M, Yoon K. Physical examination and patellofemoral pain syndrome. Am J Phys Med Rehabil. 2006;85(3):234-243.
  • Frye JL, Ramey LN, Hart JM. The effects of exercise on decreasing pain and increasing function in patients with patellofemoral pain syndrome: a systematic review. Sports Health. 2012;4(3):205-210.
  • Heintjes E, Berger MY, Bierma-Zeinstra SM, et al. Pharmacotherapy for patellofemoral pain syndrome. Cochrane Database Syst Rev. 2004;(3):CD003470.
  • Waryasz GR, McDermott AY. Patellofemoral pain syndrome (PFPS): a systematic review of anatomy and potential risk factors. Dyn Med. 2008;7:9.
See Also
&NA;
Algorithm: Knee Pain
Codes
&NA;
ICD10
  • M25.569 Pain in unspecified knee
  • M25.561 Pain in right knee
  • M25.562 Pain in left knee
Clinical Pearls
&NA;
  • Patellofemoral pain syndrome is the most common cause of anterior knee pain in active adults. Women are more commonly affected.
  • The diagnosis is made through an accurate history and physical exam. The apprehension sign is the most sensitive finding on physical exam.
  • Well-designed exercises targeting quadriceps strengthening, hamstring, and IT band flexibility and hip stabilizer stretching/strengthening are the most effective evidence-based treatment.