patellofemoral pain syndrome

The onset of the condition is usually gradual, although some cases may appear suddenly following trauma. The most common symptom is diffuse vague pain around the kneecap (peripatellar) and localized pain focused behind the kneecap (retropatellar). Affected individuals typically have difficulty describing the location of the pain. They may place their hands over the anterior patella or describe a circle around the patella. This is often called the "circle sign". Pain is usually initiated when weight is put on the knee extensor mechanism, such as when ascending or descending stairs or slopes, squatting, kneeling, cycling, or running.{{cite journal |vauthors=van der Heijden RA, Lankhorst NE, van Linschoten R, Bierma-Zeinstra SM, van Middelkoop M | year = 2013 | title = Exercise for treating patellofemoral pain syndrome (Protocol) | journal = Cochrane Database of Systematic Reviews | volume = 2 | page = CD010387 | doi = 10.1002/14651858.CD010387 | doi-access = free }}{{cite journal |vauthors=Smith TO, Drew BT, Meek TH, Clark AB | year = 2013 | title = Knee orthoses for treating patellofemoral pain syndrome (Protocol) | journal = Cochrane Database of Systematic Reviews | volume = 5 | page = CD010513 | doi = 10.1002/14651858.CD010513 | doi-access = free }} Pain during prolonged sitting is sometimes termed the "movie sign" or "theatre sign" because individuals might experience pain while sitting to watch a film or similar activity.{{cite journal | vauthors = Heintjes E, Berger MY, Bierma-Zeinstra SM, Bernsen RM, Verhaar JA, Koes BW | title = Pharmacotherapy for patellofemoral pain syndrome | journal = The Cochrane Database of Systematic Reviews | issue = 3 | pages = CD003470 | date = 2004 | volume = 2008 | pmid = 15266488 | doi = 10.1002/14651858.CD003470.pub2 | pmc = 8276350 }} The pain is typically aching and occasionally sharp. Pain may be worsened by activities.{{cite journal | vauthors = Pazzinatto MF, de Oliveira Silva D, Barton C, Rathleff MS, Briani RV, de Azevedo FM | title = Female Adults with Patellofemoral Pain Are Characterized by Widespread Hyperalgesia, Which Is Not Affected Immediately by Patellofemoral Joint Loading | journal = Pain Medicine | volume = 17 | issue = 10 | pages = 1953–1961 | date = October 2016 | pmid = 27113220 | doi = 10.1093/pm/pnw068 | doi-access = free | hdl = 11449/164758 | hdl-access = free }} The knee joint may exhibit noises such as clicking. However, this has no relation to pain and function.{{cite journal | vauthors = de Oliveira Silva D, Pazzinatto MF, Priore LB, Ferreira AS, Briani RV, Ferrari D, Bazett-Jones D, Azevedo FM | title = Knee crepitus is prevalent in women with patellofemoral pain, but is not related with function, physical activity and pain | journal = Physical Therapy in Sport | volume = 33 | pages = 7–11 | date = September 2018 | pmid = 29890402 | doi = 10.1016/j.ptsp.2018.06.002 | hdl = 11449/179928 | s2cid = 48352699 | hdl-access = free }}{{cite journal | vauthors = de Oliveira Silva D, Barton C, Crossley K, Waiteman M, Taborda B, Ferreira AS, Azevedo FM | title = Implications of knee crepitus to the overall clinical presentation of women with and without patellofemoral pain | journal = Physical Therapy in Sport | volume = 33 | pages = 89–95 | date = September 2018 | pmid = 30059950 | doi = 10.1016/j.ptsp.2018.07.007 | hdl = 11449/180174 | s2cid = 51894366 | hdl-access = free }} Giving-way of the knee may be reported. Reduced knee flexion may be experienced during activities.{{cite journal | vauthors = Silva D, Briani RV, Pazzinatto MF, Ferrari D, Aragão FA, Azevedo FM | title = Reduced knee flexion is a possible cause of increased loading rates in individuals with patellofemoral pain | journal = Clinical Biomechanics | volume = 30 | issue = 9 | pages = 971–5 | date = November 2015 | pmid = 26169602 | doi = 10.1016/j.clinbiomech.2015.06.021 }}

In most people with patellofemoral pain syndrome an examination of their history will highlight a precipitating event that caused the injury. Changes in activity patterns such as excessive increases in running mileage, repetitions such as running up steps and the addition of strength exercises that affect the patellofemoral joint are commonly associated with symptom onset. Excessively worn or poorly fitted footwear may be a contributing factor. To prevent recurrence the causal behaviour should be identified and managed correctly. The cause of pain and dysfunction often results from either abnormal forces (e.g. increased pull of the lateral quadriceps retinaculum with acute or chronic lateral patellofemoral subluxation/dislocation) or prolonged repetitive compressive or shearing forces (running or jumping) on the patellofemoral joint. The result is synovial irritation and inflammation and subchondral bony changes in the distal femur or patella known as "bone bruises".

The medical cause of PFPS is thought to be increased pressure or on the patellofemoral joint. There are several theorized mechanisms relating to how this increased pressure occurs:

• Increased levels of physical activity
• Malalignment of the patella or abnormal patellar tracking as it moves through the femoral groove. People with genu valgum have larger than normal Q-angles causing the weight-bearing line to fall lateral to the centre of the knee causing overstretching of the MCL and stressing the lateral meniscus and cartilages.{{citation needed|date=October 2020}}
• Quadriceps muscle imbalance{{cite journal | vauthors = Briani RV, De Oliveira Silva D, Flóride CS, Aragão FA, de Albuquerque CE, Magalhães FH, de Azevedo FM | title = Quadriceps neuromuscular function in women with patellofemoral pain: Influences of the type of the task and the level of pain | journal = PLoS One | volume = 13 | issue = 10 | pages = e0205553 | year = 2018 | pmid = 30304030 | pmc = 6179260 | doi = 10.1371/journal.pone.0205553 | bibcode = 2018PLoSO..1305553B | doi-access = free }}{{cite journal | vauthors = Willy RW, et al| title = Patellofemoral Pain: Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability and Health From the Academy of Orthopaedic Physical Therapy of the American Physical Therapy Association | journal = Journal of Orthopaedic & Sports Physical Therapy | volume = 49 | issue = 9 | pages = CPG1–CPG95 |pmid = 31475628| doi = 10.2519/jospt.2019.0302 | year = 2019 | doi-access = free }}
• Tight anatomical structures, e.g. retinaculum or iliotibial band
• Excessive genu valgum and repetitive motion

Patellofemoral pain syndrome can also result from fractures/trauma, internal knee derangement, osteoarthritis of the knee, and bony tumors in or around the knee.{{cite journal | title = Special tests in the clinical examination of patellofemoral syndrome | issue = 8 | pages = 287 | journal = Doctors Lounge | volume = 09 | date = 12 Aug 2009 | first = Tom | last = Plamondon | url = http://www.doctorslounge.com/index.php/articles/page/287 | access-date = 2012-08-20 | archive-date = 2012-06-29 | archive-url = https://web.archive.org/web/20120629135052/http://www.doctorslounge.com/index.php/articles/page/287 | url-status = dead }}{{self-published inline|date=July 2013}}

People can be observed standing and walking to determine patellar alignment.{{cite book | first = John F | last = Sarwark |title=Essentials of musculoskeletal care|date=2010|publisher=American Academy of Orthopaedic Surgeons|isbn=978-0-89203-579-3|location=Rosemont, Ill.|oclc=706805938}} The Q-angle, lateral hypermobility, and J-sign are commonly used to determine patellar maltracking.{{cite journal | vauthors = Sheehan FT, Derasari A, Fine KM, Brindle TJ, Alter KE | title = Q-angle and J-sign: indicative of maltracking subgroups in patellofemoral pain | journal = Clinical Orthopaedics and Related Research | volume = 468 | issue = 1 | pages = 266–75 | date = January 2010 | pmid = 19430854 | pmc = 2795830 | doi = 10.1007/s11999-009-0880-0 }} The patellofemoral glide, tilt, and grind tests (Clarke's sign), when performed, can provide strong evidence for PFPS.{{cite book | first1 = Gerard | last1 = Malanga | first2 = Scott | last2 = Nadler |url=https://books.google.com/books?id=bCN_Ux5Nj4UC&pg=PA304|title=Musculoskeletal physical examination : an evidence-based approach |date=2006|publisher=Elsevier Mosby|isbn=978-1-56053-591-1|location=Philadelphia, Penns.|pages=302–304}} Lastly, lateral instability can be assessed via the patellar apprehension test, which is deemed positive when there is pain or discomfort associated with lateral translation of the patella. Various clinical tests have been investigated for diagnostic accuracy. The Active Instability Test, knee pain during stair climbing, Clarke's test, pain with prolonged sitting, patellar inferior pole tilt, and pain during squatting have demonstrated the best accuracy. However, careful consideration is still needed when using these tests to make a differential diagnosis of PFPS.{{cite journal | vauthors = Cook C, Mabry L, Reiman MP, Hegedus EJ | title = Best tests/clinical findings for screening and diagnosis of patellofemoral pain syndrome: a systematic review | journal = Physiotherapy | volume = 98 | issue = 2 | pages = 93–100 | date = June 2012 | pmid = 22507358 | doi = 10.1016/j.physio.2011.09.001 }}

Individuals with PFP may be exhibit higher pain level and lower function.{{cite journal |vauthors = Ferreira AS, Silva DO, Priore LB, Garcia CL, Ducatti MH, Botta AF, Waiteman MC, Azevedo FM | year = 2018 | title = Differences in pain and function between adolescent athletes and physically active non-athletes with patellofemoral pain | journal = Physical Therapy in Sport | volume = 33 | pages = 70–75| doi = 10.1016/j.ptsp.2018.07.005 | pmid = 30025378 | hdl = 11449/171444 | s2cid = 51701050 | hdl-access = free }}

Magnetic resonance imaging rarely can give useful information for managing patellofemoral pain syndrome and treatment should focus on an appropriate rehabilitation program including correcting strength and flexibility concerns.{{Citation |author1 = American Medical Society for Sports Medicine |date = 24 April 2014 |title = Five Things Physicians and Patients Should Question |publisher = American Medical Society for Sports Medicine |work = Choosing Wisely: an initiative of the ABIM Foundation |url = http://www.choosingwisely.org/doctor-patient-lists/american-medical-society-for-sports-medicine/ |access-date = 29 July 2014}}, which cites

• {{cite journal | vauthors = Rixe JA, Glick JE, Brady J, Olympia RP | title = A review of the management of patellofemoral pain syndrome | journal = The Physician and Sportsmedicine | volume = 41 | issue = 3 | pages = 19–28 | date = September 2013 | pmid = 24113699 | doi = 10.3810/psm.2013.09.2023 | s2cid = 24177847 }} In the uncommon cases where a patient has mechanical symptoms like a locked knee, knee effusion, or failure to improve following physical therapy, then an MRI may give more insight into diagnosis and treatment.

PFPS is one of a handful of conditions sometimes referred to as runner's knee; the other conditions being chondromalacia patellae, iliotibial band syndrome, and plica syndrome.

Chondromalacia patellae is a term sometimes used synonymously with PFPS. However, there is general consensus that PFPS applies only to individuals without cartilage damage, thereby distinguishing it from chondromalacia patellae, a condition with softening of the patellar articular cartilage. Despite this distinction, the diagnosis of PFPS is typically made based only on the history and physical examination rather than on the results of any medical imaging. Therefore, it is unknown whether most persons with a diagnosis of PFPS have cartilage damage or not, making the difference between PFPS and chondromalacia theoretical rather than practical. It is thought that only some individuals with anterior knee pain will have true chondromalacia patellae.

{{main|Knee pain}}

The diagnosis of patellofemoral pain syndrome is made by ruling out patellar tendinitis, prepatellar bursitis, plica syndrome, Sinding-Larsen and Johansson syndrome, and Osgood–Schlatter disease.{{cite journal | vauthors = Prins MR, van der Wurff P | title = Females with patellofemoral pain syndrome have weak hip muscles: a systematic review | journal = The Australian Journal of Physiotherapy | volume = 55 | issue = 1 | pages = 9–15 | year = 2009 | pmid = 19226237 | doi = 10.1016/S0004-9514(09)70055-8 | doi-access = free }} Currently, there is not a gold standard assessment to diagnose PFPS.

A variety of treatments for patellofemoral pain syndrome are available.{{cite journal | vauthors = Bolgla LA, Boling MC | title = An update for the conservative management of patellofemoral pain syndrome: a systematic review of the literature from 2000 to 2010 | journal = International Journal of Sports Physical Therapy | volume = 6 | issue = 2 | pages = 112–25 | date = June 2011 | pmid = 21713229 | pmc = 3109895 }} Most people respond well to conservative therapy.{{cite journal | vauthors = Earl JE, Vetter CS | title = Patellofemoral pain | journal = Physical Medicine and Rehabilitation Clinics of North America | volume = 18 | issue = 3 | pages = 439–58, viii | date = August 2007 | pmid = 17678761 | doi = 10.1016/j.pmr.2007.05.004 }}

File:Vastus medialis muscle.png

Patellofemoral pain syndrome may also result from overuse or overload of the PF joint. For this reason, knee activity should be reduced until the pain is resolved.{{cite journal | vauthors = Thomeé R, Renström P, Karlsson J, Grimby G | title = Patellofemoral pain syndrome in young women. I. A clinical analysis of alignment, pain parameters, common symptoms and functional activity level | journal = Scandinavian Journal of Medicine & Science in Sports | volume = 5 | issue = 4 | pages = 237–44 | date = August 1995 | pmid = 7552769 | doi = 10.1111/j.1600-0838.1995.tb00040.x| s2cid = 46457854 }}{{cite journal | vauthors = Tria AJ, Palumbo RC, Alicea JA | title = Conservative care for patellofemoral pain | journal = The Orthopedic Clinics of North America | volume = 23 | issue = 4 | pages = 545–54 | date = October 1992 | doi = 10.1016/S0030-5898(20)31770-3 | pmid = 1408039 }}

There is consistent but low quality evidence that exercise therapy for PFPS reduces pain, improves function and aids long-term recovery. However, there is insufficient evidence to compare the effectiveness of different types of exercises with each other, and exercises with other forms of treatment.{{cite journal | vauthors = van der Heijden RA, Lankhorst NE, van Linschoten R, Bierma-Zeinstra SM, van Middelkoop M | title = Exercise for treating patellofemoral pain syndrome | journal = The Cochrane Database of Systematic Reviews | volume = 1 | pages = CD010387 | date = January 2015 | issue = 1 | pmid = 25603546 | doi = 10.1002/14651858.CD010387.pub2 | pmc = 10898323 }}

Exercise therapy is the recommended first line treatment of PFPS. Various exercises have been studied and recommended.{{cite journal|last1=van der Heijden|first1=Rianne A|last2=Lankhorst|first2=Nienke E|last3=van Linschoten|first3=Robbart|last4=Bierma-Zeinstra|first4=Sita MA|last5=van Middelkoop|first5=Marienke|last6=van Middelkoop|first6=Marienke|editor1-first=Marienke|editor1-last=Van Middelkoop|title=Exercise for treating patellofemoral pain syndrome|year=2013|doi=10.1002/14651858.CD010387|journal=Reviews|doi-access=free}} Exercises are described according to 3 parameters:

• Type of muscle activity (concentric, eccentric or isometric)
• Type of joint movement (dynamic, isometric or static)
• Reaction forces (closed or open kinetic chain)

The majority of exercise programs intended to treat PFPS are designed to strengthen the quadriceps muscles, because their weakness and quadriceps muscle imbalance may contribute to abnormal patellar tracking. If the strength of the vastus medialis muscle is inadequate, the usually larger and stronger vastus lateralis muscle will pull sideways (laterally) on the kneecap. Strengthening the vastus medialis to prevent or counter the lateral force of the vastus lateralis is one way of relieving PFPS, however it is hard to isolate and strengthen only one muscle of quadriceps.

There is also growing evidence that shows proximal factors play a much larger role than vastus medialis (VMO) strength deficits or quadriceps imbalance.{{cite journal | vauthors = de Oliveira Silva D, Barton CJ, Pazzinatto MF, Briani RV, de Azevedo FM | title = Proximal mechanics during stair ascent are more discriminate of females with patellofemoral pain than distal mechanics | journal = Clinical Biomechanics | volume = 35 | pages = 56–61 | date = June 2016 | pmid = 27128766 | doi = 10.1016/j.clinbiomech.2016.04.009 }} Hip abductor, extensor, and external rotator strengthening may help.{{cite journal |last1=Powers |first1=CM |title=The influence of abnormal hip mechanics on knee injury: a biomechanical perspective. |journal=The Journal of Orthopaedic and Sports Physical Therapy |date=February 2010 |volume=40 |issue=2 |pages=42–51 |doi=10.2519/jospt.2010.3337 |pmid=20118526|doi-access=free }} Emphasis during exercise may be placed on coordinated contraction of the medial and lateral parts of the quadriceps as well as of the hip adductor, hip abductor and gluteal muscles. Many exercise programs include stretches designed to improve lower limb flexibility.

Studies encourage additional targeted strengthening of Gluteal muscles in addition to stretching. {{Cite journal |last=Neal |first=Bradley S. |last2=Lack |first2=Simon D. |last3=Lankhorst |first3=Nienke E. |last4=Raye |first4=Andrew |last5=Morrissey |first5=Dylan |last6=van Middelkoop |first6=Marienke |date=March 2019 |title=Risk factors for patellofemoral pain: a systematic review and meta-analysis |url=https://pubmed.ncbi.nlm.nih.gov/30242107 |journal=British Journal of Sports Medicine |volume=53 |issue=5 |pages=270–281 |doi=10.1136/bjsports-2017-098890 |issn=1473-0480 |pmid=30242107}}Along with the strengthening of quad muscles these targeted exercise programs would reduce knee valgus and strengthen pelvic stability, all of which would result in less stress to the patellofemoral joint.

Electromyographic biofeedback allows visualization of specific muscle contractions and may help individuals performing the exercises to target the intended muscles during the exercise. Neuromuscular electrical stimulation to strengthen quadricep muscles is sometimes suggested, however the effectiveness of this treatment is not certain.

Inflexibility has often been cited as a source of patellofemoral pain syndrome. Stretching of the lateral knee has been suggested to help.{{cite book |first1 = Stefano | last1 = Zaffagnini | first2 = David | last2 = Dejour | first3 = Elizabeth A. | last3 = Arendt |title=Patellofemoral pain, instability, and arthritis clinical presentation, imaging, and treatment |date=2010 |publisher=Springer |location=Berlin |isbn=978-3-642-05424-2 |page=134 |url= https://books.google.com/books?id=ktGTBxRxbpEC&pg=PA134 }}

Knee and lumbar joint mobilization are not recommended as primary interventions for PFPS. It can be used as combination intervention, but as we{{who?|date=April 2024}} continue to promote use of active and physical interventions for PFPS, passive interventions such as joint mobilizations are not recommended.{{cite journal | vauthors = Collins NJ, Barton CJ, van Middelkoop M, Callaghan MJ, Rathleff MS, Vicenzino BT, Davis IS, Powers CM, Macri EM, Hart HF, de Oliveira Silva D, Crossley KM | title = 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017 | journal = British Journal of Sports Medicine | volume = 52 | issue = 18 | pages = 1170–1178 | date = September 2018 | pmid = 29925502 | doi = 10.1136/bjsports-2018-099397 | doi-access = free | hdl = 11449/171127 | hdl-access = free }}

When it comes to recovering from PFPS, it is important to build confidence in movement and encourage tissue adaptation without overloading the joint. {{Cite journal |last=Kim |first=Sungwan |last2=Wu |first2=Yin |last3=Glaviano |first3=Neal R. |last4=Pescatello |first4=Linda S. |date=2024-08-11 |title=Physical Activity Levels in Persons With Patellofemoral Pain: A Systematic Review and Meta-analysis |url=https://pubmed.ncbi.nlm.nih.gov/39129377 |journal=Sports Health |pages=19417381241264494 |doi=10.1177/19417381241264494 |issn=1941-0921 |pmc=11569677 |pmid=39129377}} There are psychological factors such as fear-avoidance and pain catastrophizing may play a role in PFPS. There is evidence that suggests that psychosocial factors, such as fear of movement and negative beliefs about pain, may contribute to prolonged symptoms in PFPS. Mentioning how these behavior patterns can affect symptoms in PFPS can highlight the importance of education of the individual’s patterns.

Manual therapy in addition to exercises helps in reducing pain, improving function, and knee range of motion in patients with PFPS. Manual therapy such as patellar joint mobilization, manipulation and soft tissue mobilization along with physical therapy exercises is found to be effective in treating PFPS. However, there is not enough evidence that supports lumbopelvic spine manipulation has any effect on the quadriceps muscle activation to improve function & reduce pain.{{cite journal |last1=Espí-López |first1=Gemma Victoria |last2=Arnal-Gómez |first2=Anna |last3=Balasch-Bernat |first3=Mercè |last4=Inglés |first4=Marta |date=June 2017 |title=Effectiveness of Manual Therapy Combined With Physical Therapy in Treatment of Patellofemoral Pain Syndrome: Systematic Review |journal=Journal of Chiropractic Medicine |volume=16 |issue=2 |pages=139–146 |doi=10.1016/j.jcm.2016.10.003 |issn=1556-3707 |pmc=5440631 |pmid=28559754}}

Non-steroidal anti-inflammatory drugs are widely used to treat PFPS; however, there is only very limited evidence that they are effective. They may reduce pain in the short term; overall, however, after three months pain is not improved. There is no evidence that one type is superior to another in PFPS, and therefore some authors have recommended that the non-steroidal with fewest side effects and which is cheapest should be used.

Glycosaminoglycan polysulfate (GAGPS) inhibits proteolytic enzymes and increases synthesis and degree of polymerization of hyaluronic acid in synovial fluid. There is contradictory evidence that it is effective in PFPS.

There is no difference in pain symptoms between taping and non-taping in individuals with PFPS.{{cite journal | vauthors = Rodriguez-Merchan EC | title = Evidence Based Conservative Management of Patello-femoral Syndrome | journal = The Archives of Bone and Joint Surgery | volume = 2 | issue = 1 | pages = 4–6 | date = March 2014 | pmid = 25207305 | pmc = 4151435 }} Although taping alone is not shown to reduce pain, studies show that taping in conjunction with therapeutic exercise can have a significant effect on pain reduction.{{cite journal | vauthors = Logan CA, Bhashyam AR, Tisosky AJ, Haber DB, Jorgensen A, Roy A, Provencher MT | title = Systematic Review of the Effect of Taping Techniques on Patellofemoral Pain Syndrome | journal = Sports Health | volume = 9 | issue = 5 | pages = 456–461 | date = September 2017 | pmid = 28617653 | pmc = 5582697 | doi = 10.1177/1941738117710938 }}

Knee braces are ineffective in treating PFPS. The technique of McConnell taping involves pulling the patella medially with tape (medial glide). Findings from some studies suggest that there is limited benefit with patella taping or bracing when compared to quadriceps exercises alone. There is a lack of evidence to show that knee braces, sleeves, or straps are effective.{{cite journal | vauthors = Smith TO, Drew BT, Meek TH, Clark AB | title = Knee orthoses for treating patellofemoral pain syndrome | journal = The Cochrane Database of Systematic Reviews | issue = 12 | pages = CD010513 | date = December 2015 | volume = 2015 | pmid = 26645724 | doi = 10.1002/14651858.CD010513.pub2 | pmc = 8763348 | url = https://ueaeprints.uea.ac.uk/56085/1/Smith_et_al_The_Cochrane_Library.pdf }}

{{Further|Knee taping}}

Low arches can cause overpronation or the feet to roll inward too much increasing load on the patellofemoral joint. Poor lower extremity biomechanics may cause stress on the knees and can be related to the development of patellofemoral pain syndrome, although the exact mechanism linking joint loading to the development of the condition is not clear. Foot orthoses can help to improve lower extremity biomechanics and may be used as a component of overall treatment.{{cite journal | vauthors = Gross ML, Davlin LB, Evanski PM | title = Effectiveness of orthotic shoe inserts in the long-distance runner | journal = The American Journal of Sports Medicine | volume = 19 | issue = 4 | pages = 409–12 | year = 1991 | pmid = 1897659 | doi = 10.1177/036354659101900416 | s2cid = 23550947 }}{{cite journal | vauthors = Eng JJ, Pierrynowski MR | s2cid = 24645828 | title = Evaluation of soft foot orthotics in the treatment of patellofemoral pain syndrome | journal = Physical Therapy | volume = 73 | issue = 2 | pages = 62–8; discussion 68–70 | date = February 1993 | pmid = 8421719 | doi = 10.1093/ptj/73.2.62 }} Foot orthoses may be useful for reducing knee pain in the short term,{{cite journal | vauthors = Hossain M, Alexander P, Burls A, Jobanputra P | title = Foot orthoses for patellofemoral pain in adults | journal = The Cochrane Database of Systematic Reviews | issue = 1 | pages = CD008402 | date = January 2011 | pmid = 21249707 | doi = 10.1002/14651858.CD008402.pub2 }} and may be combined with exercise programs or physical therapy. However, there is no evidence supporting use of combined exercise with foot orthoses as intervention beyond 12 months for adults. Evidence for long term use of foot orthoses for adolescents is uncertain. No evidence supports use of custom made foot orthoses.

{{See also|Nerve block#Genicular nerve block}}

The scientific consensus is that surgery should be avoided except in severe cases where conservative treatments have failed. The majority of individuals with PFPS receive nonsurgical treatment.

For people with chronic, severe patellofemoral pain, radiofrequency ablation of certain knee nerves may be applied as an outpatient procedure to reduce chronic arthritic pain.{{cite journal |vauthors=Conger A, Gililland J, Anderson L, Pelt CE, Peters C, McCormick ZL|display-authors=3 |title=Genicular Nerve Radiofrequency Ablation for the Treatment of Painful Knee Osteoarthritis: Current Evidence and Future Directions |journal=Pain Medicine|volume=22 |issue=Suppl 1 |pages=S20–S23 |date=July 2021 |pmid=34308957 |doi=10.1093/pm/pnab129 |url= https://academic.oup.com/painmedicine/article/22/Supplement_1/S20/6328220}} Using radiofrequency energy delivered via small electrodes positioned at target genicular nerves, the treatment achieves partial sensory denervation of the joint capsule. Despite the extensive innervation of the knee, specifically targeting the superior lateral, superior medial, and inferior medial genicular nerves has proved to be an effective ablation method for reducing chronic knee pain. In clinical research, such treatment has been shown to produce about 50% less knee pain for up to two years after the procedure.

Local injections of dilute phenol (1.5–3 ml of 6% phenol in sterile water) at three to five sensory knee nerves may be used as an alternative neurolytic treatment to relieve chronic severe knee pain.{{cite journal |vauthors=Tay MR, Mittal N, Yao S, Farag J |title=Chemical neurolysis of genicular nerves for chronic non-cancer knee pain: a scoping review |journal=Pain Medicine |volume=26 |issue=2 |pages=76–89 |date=February 2025 |pmid=39475441 |doi=10.1093/pm/pnae109 |url=https://academic.oup.com/painmedicine/article/26/2/76/7852839}}{{cite journal |vauthors=Wilkinson AJ, Chai T, Roldan CJ, Huh BK |title=Genicular nerve neurolysis with phenol for chronic knee pain: A case series |journal=Interventional Pain Medicine |volume=2 |issue=1 |pages=100182 |date=March 2023 |pmid=39239601 |pmc=11372894 |doi=10.1016/j.inpm.2023.100182}}

The use of electrophysical agents and therapeutic modalities are not recommended as passive treatments should not be the focus of the plan of care.{{cite journal | vauthors = Collins NJ, Barton CJ, van Middelkoop M, Callaghan MJ, Rathleff MS, Vicenzino BT, Davis IS, Powers CM, Macri EM, Hart HF, de Oliveira Silva D, Crossley KM | title = 2018 Consensus statement on exercise therapy and physical interventions (orthoses, taping and manual therapy) to treat patellofemoral pain: recommendations from the 5th International Patellofemoral Pain Research Retreat, Gold Coast, Australia, 2017 | journal = British Journal of Sports Medicine | volume = 52 | issue = 18 | pages = 1170–1178 | date = September 2018 | pmid = 29925502 | doi = 10.1136/bjsports-2018-099397 | doi-access = free | hdl = 11449/171127 | hdl-access = free }} There is no evidence to support the use of acupuncture or low-level laser therapy.{{cite journal | vauthors = Crossley K, Bennell K, Green S, McConnell J | title = A systematic review of physical interventions for patellofemoral pain syndrome | journal = Clinical Journal of Sport Medicine | volume = 11 | issue = 2 | pages = 103–10 | date = April 2001 | pmid = 11403109 | doi = 10.1097/00042752-200104000-00007 | s2cid = 22097250 }} Most studies claiming benefits of alternative therapies for PFPS were conducted with flawed experimental design, and therefore did not produce reliable results.{{cite journal | vauthors = Bizzini M, Childs JD, Piva SR, Delitto A | title = Systematic review of the quality of randomized controlled trials for patellofemoral pain syndrome | journal = The Journal of Orthopaedic and Sports Physical Therapy | volume = 33 | issue = 1 | pages = 4–20 | date = January 2003 | pmid = 12570282 | doi = 10.2519/jospt.2003.33.7.F4 | doi-access = free }}

Patellofemoral pain syndrome can become a chronic injury, with an estimated 50% of people reporting persistent patellar-femoral pain after a year.{{cite journal|last1=Martimbianco|first1=Ana Luiza C.|last2=Torloni|first2=Maria Regina|last3=Andriolo|first3=Brenda Ng|last4=Porfírio|first4=Gustavo Jm|last5=Riera|first5=Rachel|date=2017-12-12|title=Neuromuscular electrical stimulation (NMES) for patellofemoral pain syndrome|journal=The Cochrane Database of Systematic Reviews|volume=2017|issue=12 |pages=CD011289|doi=10.1002/14651858.CD011289.pub2|issn=1469-493X|pmc=6486051|pmid=29231243}} Risk factors for a prolonged recovery (or persistent condition) include age (older athletes), females, increased body weight, a reduction in muscle strength, time to seek care, and in those who experience symptoms for more than two months.

Patellofemoral pain syndrome is the most common cause of anterior knee pain in the outpatient.{{cite journal | vauthors = Lack S, Neal B, De Oliveira Silva D, Barton C | title = How to manage patellofemoral pain - Understanding the multifactorial nature and treatment options | journal = Physical Therapy in Sport | volume = 32 | pages = 155–166 | date = July 2018 | pmid = 29793124 | doi = 10.1016/j.ptsp.2018.04.010 | hdl = 11449/171014 | s2cid = 46921956 | hdl-access = free }} Specific populations at high risk of primary PFPS include runners, bicyclists, basketball players, young athletes and females.{{cite journal | vauthors = Atanda A, Reddy D, Rice JA, Terry MA | s2cid = 23042353 | title = Injuries and chronic conditions of the knee in young athletes | journal = Pediatrics in Review | volume = 30 | issue = 11 | pages = 419–28; quiz 429–30 | date = November 2009 | pmid = 19884282 | doi = 10.1542/pir.30-11-419 }}

BMI did not significantly increase risk of developing PFPS in adolescents. However, adults with PFPS have higher BMI than those without. It is suggested that higher BMI is associated with limited physical activity in people with PFPS as physical activity levels decrease as a result of pain associated with the condition. However, no longitudinal studies are able to show that BMI can be a predictor of development or progression of the condition.{{cite journal | vauthors = Hart HF, Barton CJ, Khan KM, Riel H, Crossley KM | title = Is body mass index associated with patellofemoral pain and patellofemoral osteoarthritis? A systematic review and meta-regression and analysis | journal = British Journal of Sports Medicine | volume = 51 | issue = 10 | pages = 781–790 | date = May 2017 | pmid = 27927675 | doi = 10.1136/bjsports-2016-096768 | s2cid = 40935953 }}

{{Reflist}}

{{Medical resources

| DiseasesDB = 33163

| ICD10 = {{ICD10|M|22|2|m|20}}

| ICD9 = {{ICD9|719.46}}

| ICDO =

| OMIM =

| MedlinePlus =

| eMedicineSubj = article

| eMedicineTopic = 308471

| MeshID = D046788

}}{{Acquired musculoskeletal deformities}}

{{Portal bar | Medicine}}

Category:Arthropathies

Category:Knee injuries and disorders

Category:Overuse injuries

Category:Syndromes

Category:Wikipedia medicine articles ready to translate