Patellofemoral Pain Syndrome

 

Am Fam Physician. 2019 Jan 15;99(2):88-94.

  Patient information: See related handout on patellofemoral pain syndrome, written by the authors of this article.

Author disclosure: No relevant financial affiliations.

Patellofemoral pain syndrome (PFPS) is one of the most common causes of anterior knee pain encountered in the outpatient setting in adolescents and adults younger than 60 years. The incidence in the United States is between 3% and 6%. The cardinal feature of PFPS is pain in or around the anterior knee that intensifies when the knee is flexed during weight-bearing activities. The pain of PFPS often worsens with prolonged sitting or descending stairs. The most sensitive physical examination finding is pain with squatting. Examining a patient's gait, posture, and footwear can help identify contributing causes. Plain radiographs of the knee are not necessary for the diagnosis of PFPS but can exclude other diagnoses, such as osteoarthritis, patellar fracture, and osteochondritis. If conservative treatment measures are unsuccessful, plain radiography is recommended. Treatment of PFPS includes rest, a short course of nonsteroidal anti-inflammatory drugs, and physical therapy directed at strengthening the hip flexor, trunk, and knee muscle groups. Patellar kinesiotaping may provide additional short-term pain relief; however, evidence is insufficient to support its routine use. Surgery is considered a last resort.

Patellofemoral pain syndrome (PFPS) is a common cause of knee pain in adolescents and adults younger than 60 years. A retrospective review of an orthopedic database including more than 30 million patients in the United States between 2007 and 2011 estimated the incidence of PFPS to be 1.75 million patients, or about 6%.1 Females accounted for 55% of cases. The highest percentage of cases occurred in the South (42%), and the lowest occurred in the Northeast (14%). In a prospective study of 1,319 healthy, physically active young adults without a previous PFPS diagnosis, 3% developed PFPS during 2.5 years of follow-up, and women were more likely to develop the condition than men.2

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SORT: KEY RECOMMENDATIONS FOR PRACTICE

Clinical recommendationEvidence ratingReferences

Exercise therapies are most effective in improving short- and long-term pain in patients with patellofemoral pain syndrome.

A

3

Short courses of nonsteroidal anti-inflammatory drugs improve pain in patients with patellofemoral pain syndrome compared with placebo, but the effect may be limited to one week.

B

28

Patellar kinesiotaping improves patellar maltracking and may reduce short-term pain as an adjunct to exercise.

B

30, 33, 34


A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to https://www.aafp.org/afpsort.

SORT: KEY RECOMMENDATIONS FOR PRACTICE

Clinical recommendationEvidence ratingReferences

Exercise therapies are most effective in improving short- and long-term pain in patients with patellofemoral pain syndrome.

A

3

Short courses of nonsteroidal anti-inflammatory drugs improve pain in patients with patellofemoral pain syndrome compared with placebo, but the effect may be limited to one week.

B

28

Patellar kinesiotaping improves patellar maltracking and may reduce short-term pain as an adjunct to exercise.

B

30, 33, 34


A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, go to https://www.aafp.org/afpsort.

Undiagnosed PFPS can cause limitations in daily physical activity and ability to exercise. There is insufficient evidence that undiagnosed PFPS contributes to patellofemoral joint osteoarthritis.35

Definition

A 2016 consensus statement defines PFPS as pain occurring around or behind the patella that is aggravated by at least one activity that loads the patella during weight-bearing on a flexed knee.4 Contributing activities include running, climbing stairs, jumping, and squatting. PFPS is also called runner's knee and anterior knee pain syndrome.4 Although the term PFPS was formerly used interchangeably with chondromalacia patellae, the latter specifically refers to the finding of softened patellofemoral cartilage on plain radiography, magnetic resonance imaging, or knee arthroscopy.6 Conversely, structural defects are absent in PFPS, and imaging is not required for the diagnosis.

Anatomy and Pathophysiology

The patellofemoral joint consists of the patella and the trochlea of the femur and is important in knee extension and deceleration7 (Figure 18). The patella acts as a lever within the leg, decreasing the amount of force required by the quadriceps to extend the leg at the knee. The patellofemoral joint is stabilized by the quadriceps, patellar tendon, vastus medialis obliquus, medial patellofemoral ligament, medial patellotibial ligament, medial retinaculum, oblique lateral retinaculum, patellotibial band, epicondylopatellar bands, and lateral retinaculum.9

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FIGURE 1.

Schematic of the right knee, anterior view. Dynamic stability of the patellofemoral joint is provided by the quadriceps tendon, patellar ligament, vastus medialis obliquus, vastus lateralis, and iliotibial band. The vastus medialis obliquus is the only muscle that provides a medial force and is therefore of particular importance in stabilizing the patella. Static stability is provided via the articular capsule, the femoral trochlea, the medial and lateral retinacula, and the patellofemoral ligaments. Palpation of the bony and soft tissue structures should be performed in an attempt to identify the anatomic site of the pain.

Illustration by Todd Buck

Reprinted with permission from Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75(2):195.


FIGURE 1.

Schematic of the right knee, anterior view. Dynamic stability of the patellofemoral joint is provided by the quadriceps tendon, patellar ligament, vastus medialis obliquus, vastus lateralis, and iliotibial band. The vastus medialis obliquus is the only muscle that provides a medial force and is therefore of particular importance in stabilizing the patella. Static stability is provided via the articular capsule, the femoral trochlea, the medial and lateral retinacula, and the patellofemoral ligaments. Palpation of the bony and soft tissue structures should be performed in an attempt to identify the anatomic site of the pain.

Illustration by Todd Buck

Reprinted with permission from Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75(2):195.

The force of the quadriceps is measured by the angle formed from the anterior superior iliac spine to the center of the patella to the tibial tubercle, which is known as the Q angle10 (Figure 211). The Q angle is approximately 14 degrees in men and 17 degrees in women.12 Because lateral forces on the patella are increased with higher Q angles, it has long been thought that a high Q angle increases the risk of PFPS; however, a higher Q angle has not been shown to be a clear contributing cause of PFPS in more recent research.1214

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FIGURE 2.

Quadriceps force is measured by the angle formed from the anterior superior iliac spine to the center of the patella to the tibial tubercle (Q angle).

Illustration by Floyd E. Hosmer

Reprinted with permission from Juhn MS. Patellofemoral pain syndrome: a review and guidelines for treatment [published correction appears in Am Fam Physician. 2000;61(4):960, 965]. Am Fam Physician. 1999;60(7):2014.


FIGURE 2.

Quadriceps force is measured by the angle formed from the anterior superior iliac spine to the center of the patella to the tibial tubercle (Q angle).

Illustration by Floyd E. Hosmer

Reprinted with permission from Juhn MS. Patellofemoral pain syndrome: a review and guidelines for treatment [published correction appears in Am Fam Physician. 2000;61(4):960, 965]. Am Fam Physician. 1999;60(7):2014.

Patellar maltracking is believed to play a role in PFPS. Patellar maltracking, or lateral translation, increases with load-bearing positions, such as squatting, in patients with PFPS. Stimulation of nerve endings within the retinacula, Hoffa (infrapatellar) fat pad, and peripatellar synovium may also contribute to the development of PFPS.15

Risk Factors

Established risk factors for PFPS (Table 1) include female sex and activities such as running, squatting, and going up and down stairs.1,2,16 In addition, a systematic review showed that decreased quadriceps strength was associated with a significantly higher risk of PFPS, likely because it can lead to patellar instability.16 Other etiologies of patellar instability, such as knee sprains, may also contribute to PFPS.17

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TABLE 1.

Risk Factors for Patellofemoral Pain Syndrome

Activities such as running, squatting, and climbing up and down stairs

Dynamic valgus (increases patellar maltracking)

Female sex

Foot abnormalities (rearfoot eversion and pes pronatus)

Overuse or sudden increase in physical activity level

Patellar instability

Quadriceps weakness


Information from references 1, 2, and 16.

TABLE 1.

Risk Factors for Patellofemoral Pain Syndrome

Activities such as running, squatting, and climbing up and down stairs

Dynamic valgus (increases patellar maltracking)

Female sex

Foot abnormalities (rearfoot eversion and pes pronatus)

Overuse or sudden increase in physical activity level

Patellar instability

Quadriceps weakness


Information from references 1, 2, and 16.

Dynamic valgus is another mechanism associated with PFPS. Dynamic valgus is a body position in which the knee collapses medially from excessive valgus, internal-external rotation, or both.18 This increases the lateral force on the patella, contributing to maltracking. Dynamic valgus is more common in female athletes, which may account for the higher incidence of PFPS in females.19 Foot abnormalities, such as rearfoot eversion and pes pronatus, lead to internal rotation of the tibia, which can also contribute to dynamic valgus.20

Diagnosis

The differential diagnosis of anterior knee pain is extensive (Table 28). PFPS is usually diagnosed using history and physical examination findings.

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TABLE 2.

Differential Diagnosis of Anterior Knee Pain

CauseComment

Articular cartilage injury

Possible history of trauma; mechanical symptoms may occur if loose body is present

Bone tumors

Pain may be insidious; may have tenderness of bony structures

Chondromalacia patellae

Retropatellar pain, may have history of trauma, may have effusion on examination

Hoffa disease

Pain and tenderness localized to the Hoffa (infrapatellar) fat pad

Iliotibial band syndrome

Typically presents as lateral pain and tenderness over the lateral femoral epicondyle

Lateral patellar compression syndrome

Poor patellar alignment sometimes caused by a tight lateral retinaculum results in anterior knee pain

Loose bodies

Symptoms vary; may have intermittent sharp pain, locking, or effusion

Osgood-Schlatter disease

Tenderness and swelling at patellar tendon insertion at the tibial tubercle in an adolescent

Osteochondritis dissecans

Symptoms vary; may have intermittent pain, swelling, or locking

Patellar instability/subluxation

Intermittent pain with the sensation of instability or movement of the patella; may have swelling; locking can occur with loose body formation; may have tenderness over the medial retinaculum

Patellar stress fracture

May have tenderness directly over the patella

Patellar tendinopathy

Tenderness of the tendon; tendon may be thickened if chronic

Patellofemoral osteoarthritis

May have crepitus or effusion; characteristic radiographic findings

Patellofemoral pain syndrome

Pain in or around the anterior knee that intensifies when the knee is flexed during weight-bearing activities; usually no effusion; may have findings of patellar maltracking

Pes anserine bursitis

Pain usually described as medial rather than anterior; tenderness over the pes anserine bursa

Plica syndrome

May be medial or lateral to the patella; if symptomatic, tenderness can be demonstrated on examination

Prepatellar bursitis

Characteristic swelling anterior to the patella following trauma

Quadriceps tendinopathy

Tenderness over the tendon

Referred pain from the lumbar spine or hip joint pathology

Symptoms depend on the origin of pain; knee examination is usually normal

Saphenous neuritis

Pain is usually medial but poorly localized; may have history of surgery

Sinding-Larsen-Johansson syndrome

Tenderness at the patellar tendon insertion at the inferior pole of the patella in an adolescent

Symptomatic bipartite patella

May have tenderness directly over the patella with characteristic radiographic findings


Adapted with permission from Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75(2):196.

TABLE 2.

Differential Diagnosis of Anterior Knee Pain

CauseComment

Articular cartilage injury

Possible history of trauma; mechanical symptoms may occur if loose body is present

Bone tumors

Pain may be insidious; may have tenderness of bony structures

Chondromalacia patellae

Retropatellar pain, may have history of trauma, may have effusion on examination

Hoffa disease

Pain and tenderness localized to the Hoffa (infrapatellar) fat pad

Iliotibial band syndrome

Typically presents as lateral pain and tenderness over the lateral femoral epicondyle

Lateral patellar compression syndrome

Poor patellar alignment sometimes caused by a tight lateral retinaculum results in anterior knee pain

Loose bodies

Symptoms vary; may have intermittent sharp pain, locking, or effusion

Osgood-Schlatter disease

Tenderness and swelling at patellar tendon insertion at the tibial tubercle in an adolescent

Osteochondritis dissecans

Symptoms vary; may have intermittent pain, swelling, or locking

Patellar instability/subluxation

Intermittent pain with the sensation of instability or movement of the patella; may have swelling; locking can occur with loose body formation; may have tenderness over the medial retinaculum

Patellar stress fracture

May have tenderness directly over the patella

Patellar tendinopathy

Tenderness of the tendon; tendon may be thickened if chronic

Patellofemoral osteoarthritis

May have crepitus or effusion; characteristic radiographic findings

Patellofemoral pain syndrome

Pain in or around the anterior knee that intensifies when the knee is flexed during weight-bearing activities; usually no effusion; may have findings of patellar maltracking

Pes anserine bursitis

Pain usually described as medial rather than anterior; tenderness over the pes anserine bursa

Plica syndrome

May be medial or lateral to the patella; if symptomatic, tenderness can be demonstrated on examination

Prepatellar bursitis

Characteristic swelling anterior to the patella following trauma

Quadriceps tendinopathy

Tenderness over the tendon

Referred pain from the lumbar spine or hip joint pathology

Symptoms depend on the origin of pain; knee examination is usually normal

Saphenous neuritis

Pain is usually medial but poorly localized; may have history of surgery

Sinding-Larsen-Johansson syndrome

Tenderness at the patellar tendon insertion at the inferior pole of the patella in an adolescent

Symptomatic bipartite patella

May have tenderness directly over the patella with characteristic radiographic findings


Adapted with permission from Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75(2):196.

HISTORY

The cardinal feature of PFPS is pain in or around the anterior knee that intensifies when the knee is flexed during weight-bearing activities.4 Patients may also have pain or stiffness exacerbated by prolonged sitting with the knee in flexion.8

Patients should be asked about previous knee injuries and surgeries, current activity level, and recent changes in activity. PFPS is a common form of knee overuse injury. Less commonly, patients may experience knee buckling, which is due to weakness or pain in the quadriceps resulting in a brief loss of muscle tone, not instability of the intrinsic knee joint.8 Locking and clicking in the knee are not consistent with PFPS, and instead suggest internal knee derangements such as meniscal tears.

PHYSICAL EXAMINATION

A physical examination of the knee should be performed in all patients presenting with a chief symptom of knee pain. Large joint effusion, erythema, and increased warmth are not features of PFPS and should prompt consideration of an alternative diagnosis such as infection, acute trauma, and inflammatory arthropathy.

In a meta-analysis, the presence of pain with squatting was the most sensitive physical examination finding for PFPS, and a positive result on the patellar tilt test carried the highest positive likelihood ratio.21  Table 3 includes commonly performed physical examination tests and their value in diagnosing PFPS.2123

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TABLE 3.

Diagnostic Value of Physical Examination Maneuvers for Patellofemoral Pain Syndrome

Test Sensitivity (%)Specificity (%) LR–LR+

Clarke test (https://www.youtube.com/watch?v=pRqnODPqxFs)*

39 to 48

67 to 75

0.7 to 0.91

1.18

Medial or lateral patellar facet tenderness†

92

65

0.96

Not determined

Pain during squatting

91

50

0.2

1.8

Patellar apprehension test (https://www.youtube.com/watch?v=4TnCQppTy1g)

7 to 32

86 to 92

0.8 to 1.0

0.9 to 2.3

Patellar tilt test (https://www.youtube.com/watch?v=DlHoesKkvTM)

43

92

0.6

5.4


LR+ = positive likelihood ratio; LR− = negative likelihood ratio.

*—Performed with patient supine and leg extended. The examiner applies pressure to the superior aspect of the patella while the patient performs isometric contraction of the quadriceps. The test is considered positive if the contraction cannot be sustained for more than two seconds.

†—In patients younger than 58 years with pain isolated to the anterior knee.

Information from references 21 through 23.

TABLE 3.

Diagnostic Value of Physical Examination Maneuvers for Patellofemoral Pain Syndrome

Test Sensitivity (%)Specificity (%) LR–LR+

Clarke test (https://www.youtube.com/watch?v=pRqnODPqxFs)*

39 to 48

67 to 75

0.7 to 0.91

1.18

Medial or lateral patellar facet tenderness†

92

65

0.96

Not determined

Pain during squatting

91

50

0.2

1.8

Patellar apprehension test (https://www.youtube.com/watch?v=4TnCQppTy1g)

7 to 32

86 to 92

0.8 to 1.0

0.9 to 2.3

Patellar tilt test (https://www.youtube.com/watch?v=DlHoesKkvTM)

43

92

0.6

5.4


LR+ = positive likelihood ratio; LR− = negative likelihood ratio.

*—Performed with patient supine and leg extended. The examiner applies pressure to the superior aspect of the patella while the patient performs isometric contraction of the quadriceps. The test is considered positive if the contraction cannot be sustained for more than two seconds.

†—In patients younger than 58 years with pain isolated to the anterior knee.

Information from references 21 through 23.

Examining the patient's gait and posture is also helpful in identifying contributing causes of PFPS, such as exaggerated lumbar lordosis, asymmetric hip height, or atrophic quadriceps, which in turn helps guide physical therapy.7 The patient's footwear should also be inspected. Excess wear patterns on the medial aspect of the shoe could suggest pes pronatus (https://www.youtube.com/watch?v=Wxx7O8HoOzI) or rearfoot eversion (https://www.youtube.com/watch?v=fiHX1ZWUl6c).8 Tight hamstrings have been associated with patellofemoral pain, possibly because of cocontraction of the hamstrings and quadriceps causing increased forces on the joint during exercise.24,25 Tight hamstrings can be assessed using the passive knee extension test (https://www.physio-pedia.com/Passive_knee_extension_test).

IMAGING

Although PFPS is a clinical diagnosis, imaging may be helpful to rule out other causes of knee pain. Imaging may be beneficial if the patient's pain has not improved after four to eight weeks of conservative measures. Plain radiography of the knee can rule out osteoarthritis in patients older than 50 years, patellar fractures in patients with a history of trauma, and osteochondritis if these diagnoses are suggested by the history or physical examination.7 The anteroposterior, lateral, and sunrise or Merchant views can be particularly helpful. Structural abnormalities such as minor patellar cartilage defects, bone marrow lesions, and increased signal in the Hoffa fat pad that are visible on magnetic resonance imaging are not associated with PFPS.26 Therefore, magnetic resonance imaging is not recommended in the evaluation for PFPS.26

Treatment

Treatment of PFPS should focus on early pain relief.27 Relative rest, ice, and analgesics are recommended to reduce pain, but physical therapy is the cornerstone of treatment.

MEDICATIONS

Analgesics, such as nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and glycosaminoglycan polysulphates, have been studied in randomized trials. A 2004 Cochrane review of pharmacotherapy for PFPS found low-quality evidence and conflicting results.28 If analgesics are used, a short course of NSAIDs is preferred. In one small double-blind randomized trial, one week of naproxen improved pain compared with placebo. High-quality studies showing pain reduction with longer courses of NSAIDs are lacking.28

PHYSICAL THERAPY

Because of the multiple contributing factors of PFPS, therapy should be individualized.27 Exacerbating movements or activities should be avoided, although the patient should otherwise remain as active as possible.5 A Cochrane review concluded that patients who exercise generally have improvement in short-term and long-term pain, both at rest and with activity, when compared with those who do not exercise.3 Exercise regimens should focus on the hip, trunk, and knee. There are no high-quality data to recommend one type of exercise over another.3 Core muscle strengthening reduces pressure on the patellofemoral joint by stabilizing muscle recruitment.29 Strengthening exercises and flexibility training of the associated muscle groups should be performed three times per week for six to eight weeks.30 Several commonly recommended exercises were illustrated previously in American Family Physician (https://www.aafp.org/afp/2015/1115/p875.html#sec-2).30 Exercise should be continued for long-term pain relief and improved functionality.31

OTHER THERAPIES

Beyond rest and exercise, other early therapies for PFPS include taping and foot orthotics.32 Kinesiotaping (Figure 3) can temporarily help improve patellar maltracking in athletes, although it is likely more beneficial earlier in the course of PFPS.30 In a single randomized trial of 90 patients, kinesiotaping improved short-term pain when added to exercises and physical therapy.33 However, a Cochrane review of five older trials found that the overall evidence is insufficient to recommend routine use of kinesiotaping.34 Foot orthotics can help correct dynamic valgus secondary to pes pronatus and rearfoot eversion, although it is unclear if they reduce pain.3335 Combining exercise with foot orthotics is likely more beneficial than either treatment alone. Knee braces have not demonstrated benefit over exercise.36

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FIGURE 3.

Proper placement of kinesiotape. The initial piece of tape is placed as an inverted Y along the anterior portion of thigh with distal pieces placed on medial and lateral aspects of the patella. A second piece of tape is placed over the distal portion of the Y tape anchoring the tape inferior to the patella.


FIGURE 3.

Proper placement of kinesiotape. The initial piece of tape is placed as an inverted Y along the anterior portion of thigh with distal pieces placed on medial and lateral aspects of the patella. A second piece of tape is placed over the distal portion of the Y tape anchoring the tape inferior to the patella.

Patellofemoral mobilizations and electrophysical therapies such as therapeutic ultrasound and transcutaneous electrical nerve stimulation are not recommended.31 Surgery has not been studied sufficiently to demonstrate improved clinical outcomes over conservative strategies, and should be performed only after conservative measures have failed and subsequent imaging elucidates a surgical indication.37

This article updates previous articles on this topic by Dixit, et al.,8 and Juhn.11

Data Sources: The search strategy centered primarily on identifying systematic reviews, meta-analyses, and randomized controlled trials that focused on treatment of patellofemoral pain syndrome. The key words used were patellofemoral pain syndrome, specifically conservative treatment, risk factors, demographics, Q angle, taping, exercise, and patellofemoral joint anatomy. Key sources included PubMed, Cochrane, UpToDate, Essential Evidence Plus, and the references from the 2009 AFP article on patellofemoral pain syndrome. Search dates: September 13 to December 18, 2017.

The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the U.S. Army Medical Department or the U.S. Army Service at large.

The Authors

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DAVID Y. GAITONDE, MD, is a core clinical faculty member and chief of endocrinology service at Dwight D. Eisenhower Army Medical Center, Fort Gordon, Ga....

ALEX ERICKSEN, MD, is a second-year resident in the Internal Medicine Residency Program at Dwight D. Eisenhower Army Medical Center.

RACHEL C. ROBBINS, MD, is chief of rheumatology service and associate program director of the Internal Medicine Residency Program at Dwight D. Eisenhower Army Medical Center.

Address correspondence to David Y. Gaitonde, MD, Dwight D. Eisenhower Army Medical Center, 300 E. Hospital Rd., Fort Gordon, GA 30905. Reprints are not available from the authors.

Author disclosure: No relevant financial affiliations.

References

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1. Glaviano NR, Kew M, Hart JM, Saliba S. Demographic and epidemiological trends in patellofemoral pain. Int J Sports Phys Ther. 2015;10(3):281–290....

2. Boling MC, Padua DA, Marshall SW, Guskiewicz K, Pyne S, Beutler A. A prospective investigation of biomechanical risk factors for patellofemoral pain syndrome: the Joint Undertaking to Monitor and Prevent ACL Injury (JUMP-ACL) cohort. Am J Sports Med. 2009;37(11):2108–2116.

3. van der Heijden RA, Lankhorst NE, van Linschoten R, Bierma-Zeinstra SM, van Middelkoop M. Exercise for treating patellofemoral pain syndrome. Cochrane Database Syst Rev. 2015;(1):CD010387.

4. Crossley KM, Stefanik JJ, Selfe J, et al. 2016 patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 1: terminology, definitions, clinical examination, natural history, patellofemoral osteoarthritis and patient-reported outcome measures. Br J Sports Med. 2016;50(14):839–843.

5. Thomas MJ, Wood L, Selfe J, Peat G. Anterior knee pain in younger adults as a precursor to subsequent patellofemoral osteoarthritis: a systematic review. BMC Musculoskelet Disord. 2010;11:201.

6. Pihlajamäki HK, Kuikka PI, Leppänen VV, Kiuru MJ, Mattila VM. Reliability of clinical findings and magnetic resonance imaging for the diagnosis of chondromalacia patellae. J Bone Joint Surg Am. 2010;92(4):927–934.

7. Patel DR, Villalobos A. Evaluation and management of knee pain in young athletes: overuse injuries of the knee. Transl Pediatr. 2017;6(3):190–198.

8. Dixit S, DiFiori JP, Burton M, Mines B. Management of patellofemoral pain syndrome. Am Fam Physician. 2007;75(2):194–202.

9. Sherman SL, Plackis AC, Nuelle CW. Patellofemoral anatomy and biomechanics. Clin Sports Med. 2014;33(3):389–401.

10. Petersen W, Rembitzki I, Liebau C. Patellofemoral pain in athletes. Open Access J Sports Med. 2017;8:143–154.

11. Juhn MS. Patellofemoral pain syndrome: a review and guidelines for treatment [published correction appears in Am Fam Physician. 2000;61(4):960, 965]. Am Fam Physician. 1999;60(7):2012–2022.

12. Almeida GP, Silva AP, França FJ, Magalhães MO, Burke TN, Marques AP. Q-angle in patellofemoral pain: relationship with dynamic knee valgus, hip abductor torque, pain and function. Rev Bras Ortop. 2016;51(2):181–186.

13. Pappas E, Wong-Tom WM. Prospective predictors of patellofemoral pain syndrome: a systematic review with meta-analysis. Sports Health. 2012;4(2):115–120.

14. Park SK, Stefanyshyn DJ. Greater Q angle may not be a risk factor of patellofemoral pain syndrome. Clin Biomech (Bristol, Avon). 2011;26(4):392–396.

15. Wojtys EM, Beaman DN, Glover RA, Janda D. Innervation of the human knee joint by substance-P fibers. Arthroscopy. 1990;6(4):254–263.

16. 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.

17. Jeon K, Seo BD, Lee SH. Comparative study on isokinetic capacity of knee and ankle joints by functional injury. J Phys Ther Sci. 2016;28(1):250–256.

18. Schmitz RJ, Shultz SJ, Nguyen AD. Dynamic valgus alignment and functional strength in males and females during maturation. J Athl Train. 2009;44(1):26–32.

19. Myer GD, Ford KR, Barber Foss KD, et al. The incidence and potential pathomechanics of patellofemoral pain in female athletes. Clin Biomech (Bristol, Avon). 2010;25(7):700–707.

20. Barton CJ, Levinger P, Crossley KM, Webster KE, Menz HB. The relationship between rearfoot, tibial and hip kinematics in individuals with patellofemoral pain syndrome. Clin Biomech (Bristol, Avon). 2012;27(7):702–705.

21. Nunes GS, Stapait EL, Kirsten MH, de Noronha M, Santos GM. Clinical test for diagnosis of patellofemoral pain syndrome: systematic review with meta-analysis. Phys Ther Sport. 2013;14(1):54–59.

22. Doberstein ST, Romeyn RL, Reineke DM. The diagnostic value of the Clarke sign in assessing chondromalacia patella. J Athl Train. 2008;43(2):190–196.

23. Décary S, Frémont P, Pelletier B, et al. Validity of combining history elements and physical examination tests to diagnose patellofemoral pain. Arch Phys Med Rehabil. 2018;99(4):607–614.e1.

24. White LC, Dolphin P, Dixon J. Hamstring length in patellofemoral pain syndrome. Physiotherapy. 2009;95(1):24–28.

25. Besier TF, Fredericson M, Gold GE, Beaupré GS, Delp SL. Knee muscle forces during walking and running in patellofemoral pain patients and pain-free controls. J Biomech. 2009;42(7):898–905.

26. van der Heijden RA, de Kanter JL, Bierma-Zeinstra SM, et al. Structural abnormalities on magnetic resonance imaging in patients with patellofemoral pain: a cross-sectional case-control study. Am J Sports Med. 2016;44(9):2339–2346.

27. Matthews M, Rathleff MS, Claus A, et al. The Foot Orthoses versus Hip eXercises (FOHX) trial for patellofemoral pain: a protocol for a randomized clinical trial to determine if foot mobility is associated with better outcomes from foot orthoses. J Foot Ankle Res. 2017;10:5.

28. Heintjes E, Berger MY, Bierma-Zeinstra SM, Bernsen RM, Verhaar JA, Koes BW. Pharmacotherapy for patellofemoral pain syndrome. Cochrane Database Syst Rev. 2004;(3):CD003470.

29. Chevidikunnan MF, Al Saif A, Gaowgzeh RA, Mamdouh KA. Effectiveness of core muscle strengthening for improving pain and dynamic balance among female patients with patellofemoral pain syndrome. J Phys Ther Sci. 2016;28(5):1518–1523.

30. Jones BQ, Covey CJ, Sineath MH Jr. Nonsurgical management of knee pain in adults. Am Fam Physician. 2015;92(10):875–883.

31. Crossley KM, van Middelkoop M, Callaghan MJ, Collins NJ, Rathleff MS, Barton CJ. 2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions (exercise, taping, bracing, foot orthoses and combined interventions). Br J Sports Med. 2016;50(14):844–852.

32. Ahmed Hamada H, Hussein Draz A, Koura GM, Saab IM. Carryover effect of hip and knee exercises program on functional performance in individuals with patellofemoral pain syndrome. J Phys Ther Sci. 2017;29(8):1341–1347.

33. Kurt EE, Büyükturan Ö, Erdem HR, Tuncay F, Sezgin H. Short-term effects of kinesio tape on joint position sense, isokinetic measurements, and clinical parameters in patellofemoral pain syndrome. J Phys Ther Sci. 2016;28(7):2034–2040.

34. Callaghan MJ, Selfe J. Patellar taping for patellofemoral pain syndrome in adults. Cochrane Database Syst Rev. 2012;(4):CD006717.

35. Hossain M, Alexander P, Burls A, Jobanputra P. Foot orthoses for patellofemoral pain in adults. Cochrane Database Syst Rev. 2011;(1):CD008402.

36. Swart NM, van Linschoten R, Bierma-Zeinstra SM, van Middelkoop M. The additional effect of orthotic devices on exercise therapy for patients with patellofemoral pain syndrome: a systematic review. Br J Sports Med. 2012;46(8):570–577.

37. Rixe JA, Glick JE, Brady J, Olympia RP. A review of the management of patellofemoral pain syndrome. Phys Sportsmed. 2013;41(3):19–28.

 

 

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