Patellofemoral pain syndrome (anterior knee pain) Updated 2026

Clinical synthesis based on the JOSPT 2019 CPG (Willy), the Manchester 2016 and Gold Coast 2018 international consensus statements, and the 2022-2025 meta-analyses (Winters NMA, Mansfield NMA, Hsu prognosis).

Patellofemoral pain syndrome (PFP), also called patellofemoral pain (PFP), or more broadly “anterior knee pain”, refers to pain located behind or around the patella, provoked or aggravated by activities that load the patellofemoral joint in flexion.¹ ² It is not an organ-based diagnosis but a clinical syndrome whose diagnostic coherence was restated by the 4th International Patellofemoral Pain Research Retreat (Manchester, 2016) and then by the JOSPT 2019 CPG.¹ ²

How is this condition defined, who is affected and what are the risk factors?

Diagnosis of PFP rests on three main elements according to the Manchester international consensus²:

• Retro- or peripatellar pain lasting more than 6 weeks, of insidious onset or linked to an increase in load.
• Pain reproduced by at least one activity that loads the patellofemoral joint in flexion such as squatting, descending stairs, running, jumping or prolonged sitting (the “cinema sign”).
• Exclusion of the other causes of anterior knee pain (patellar tendinopathy, plica, Hoffa, meniscal, ligamentous, osteochondral, neuropathic).¹

The SR/MA by Smith et al. published in PLoS One in 2018 remains the epidemiological reference: pooling 23 studies, it reports an annual prevalence of 22.7% in the general population and of 28.9% in adolescents, making PFP one of the most frequent musculoskeletal conditions of the lower limb. 🦵⁴

PFP preferentially affects adolescents and young adults (15-40 years), with a well-documented female over-representation . The SR/MA by Neal et al. (BJSM 2019) identified three groups of risk factors with a sufficient level of evidence:⁵

• Quadriceps weakness measured at baseline (the most consistent evidence, prospective predictor).
• Weakness of the hip muscles (abductors, external rotators), a risk factor in women in particular.
• Lateral patellar hyperpressure and altered motor control during weight-bearing tasks (single-leg squat, landing).

Conversely, several long-invoked factors have been downgraded: the Q angle is not a reliable predictor, static patellar malalignment on imaging is not correlated with pain, and excessive foot pronation has only a modest effect confined to a subgroup.⁵ ⁶ The pathomechanical model proposed by Powers, Witvrouw, Davis and Crossley (BJSM 2017) brings all these elements together in a simple equation: joint stress = force / contact area, modulated by proximal factors (hip, trunk), local factors (quadriceps, peripatellar tissues) and distal factors (foot, ankle).⁶

What happens inside the body and how does PFP evolve naturally?

PFP is neither an inflammatory condition nor an obligatory structural lesion. The concept of “chondromalacia”, long invoked, is now largely abandoned as an aetiology: 30 to 50% of asymptomatic individuals show patellofemoral cartilage abnormalities on MRI without any pain.¹ ⁷ The dominant pathophysiological model is that of tissue homeostasis proposed by Scott Dye (2005, Clin Orthop Relat Res): PFP arises when the load applied to the joint exceeds the envelope of function : the individual capacity of the tissues to tolerate stress without pain.⁷

The finite element study by Farrokhi, Keyak and Powers (Osteoarthritis Cartilage 2011) quantified this phenomenon: individuals with PFP show mean patellar stress 1.3 to 1.5 times higher than asymptomatic controls during squats at 15° and 45° of flexion.⁸ The structures responsible for the pain are multiple (subchondral bone, retinaculum, infrapatellar fat pad (Hoffa), synovium) and all richly innervated.⁷

The natural history is frequently unfavourable, which contradicts the old perception of a benign, self-limiting condition. The recent SR/MA by Hsu et al. published in JOSPT in 2025 synthesised the available prospective studies and shows that a substantial proportion of patients remain symptomatic well beyond the initial course of management.⁹ In adolescents, cohort data report up to 75% persistent pain at 1 year and 50-90% in the long term (1-20 years).¹⁰ In adults, the SR by Collins et al. (BMC Musculoskelet Disord 2010) had already identified as predictors of a poor long-term outcome: symptom duration before the first consultation, high baseline pain, and persistent quadriceps weakness.¹¹

A direct consequence: long-standing PFP is a possible risk factor for patellofemoral osteoarthritis later on (PFOA), although direct causality remains debated.² ¹² This reinforces the idea that early, structured management is not a comfort but a prognostic issue. 📉

Diagnosis of PFP is essentially clinical , one of the most robust messages of the JOSPT 2019 CPG and of the Manchester 2016 consensus.¹ ² Imaging is not recommended routinely and should be used only where there is a red flag or a suspected structural differential diagnosis.¹

Which questions should you ask to understand the patient and their history?

The history aims to reconstruct the load story and to isolate the diagnostic features:

• Location : the pain must be retro- or peripatellar. Ask the patient to point to the painful area with one finger: a patient with PFP often makes the “C” sign around the kneecap. Pain that is very localised over the inferior pole of the patella points instead to patellar tendinopathy.¹ ¹³
• Provocative activities : at least one activity loading the patellofemoral joint in flexion (descending stairs, squatting, running, landing from a jump). The prolonged sitting (“cinema sign”) is a historical but non-specific sign: Smith 2018 finds it in around 50% of PFP cases.²
• Mode of onset : insidious, most often after a rapid increase in load (going from 0 to 30 km of running per week, taking up a sport, changing shoes, changing surface).¹ ¹⁴
• Pain behaviour : worsened by loading in flexion, relieved by rest. Night pain, mechanical pain at rest, or pain unrelated to activity should raise the suspicion of a red flag.¹⁵
• Psychosocial factors : kinesiophobia, catastrophising, fear of recurrence, low self-efficacy. The SR by Maclachlan et al. (BJSM 2017) confirms their correlation with severity and persistence.¹⁶

Which clinical tests should you carry out and which other conditions must be ruled out?

No single test is sufficient: the strategy is to combine several tests to raise the cumulative diagnostic value.¹

Tests with solid diagnostic value:

• Bilateral squat has high sensitivity (≈ 80%) for reproducing PFP pain.¹
• Palpation of the patellar facets (with the patella tilted medially and laterally) reproduces the familiar pain in the majority of PFP cases.¹
• Single-leg squat / step-down test reproduces the pain under single-leg loading and allows a qualitative analysis of motor control (dynamic knee valgus, trunk lean, pelvic drop).¹

⚠️ Historical tests to abandon as a first choice, because their diagnostic value is low:

• Clarke's test (patellar grind sign, “Zohlen”): poor reproducibility, many false positives in asymptomatic people.¹⁷
• Isolated active patellar compression.
• Static measurement of the Q angle (poorly correlated with risk, poor intra-observer reliability).⁵

The examination is not limited to provocation tests. It must explicitly assess the modifiable deficits that will become the therapeutic targets :

• Quadriceps strength measured with a hand-held dynamometer (HHD) or a functional test under progressive load. A deficit ≥ 10% versus the healthy side is clinically relevant.¹ ⁵
• Strength of the hip abductors and external rotators is a key factor in women (Nascimento 2018).¹⁸
• Motor control under load judged on the quality of the single-leg squat / step-down (valgus, contralateral trunk drop).
• Mobility covering quadriceps flexibility (Ely test, modified Thomas test), the hamstrings and the gastrocnemius (weight-bearing dorsiflexion).

The differential diagnoses to know when faced with anterior knee pain:¹ ¹³ ¹⁹

• Patellar tendinopathy gives sharp pain at the inferior pole of the kneecap, aggravated by energy storage and release (jumping, downhill work).
• Hoffa syndrome gives pain on either side of the patellar tendon, increased by forced extension.
• Medial synovial plica syndrome gives an audible snap and mediopatellar pain, sometimes resistant to standard conservative treatment. Beware, this is a diagnosis of exclusion: the plica is a normal fold, present in more than one healthy knee in three.
• Neuralgia of the infrapatellar branch of the saphenous nerve gives band-like anteromedial pain with localised hypersensitivity, often after arthroscopy or trauma.²⁰
• Early patellofemoral osteoarthritis occurs in an older patient, with morning stiffness and crepitus.
• Meniscal or osteochondral lesion involves a history of trauma, locking and recurrent effusion.

Should patients with PFP be classified, and for what benefit?

The idea of subtyping patients with PFP in order to target treatment better has been championed since 2016 by the TIPPs group (Targeted Interventions for Patellofemoral Pain) of Selfe, Janssen and Callaghan. Their observational study of 127 patients published in BJSM in 2016 identified three main subgroups according to the profile of strength, mobility and foot type.²¹

The classification approaches most discussed today:

1. Overload / training error means no major muscle deficit, but a rapid increase in load. Target: load management, education.
2. Strength deficit (hip and/or quadriceps): progressive strengthening and heavy resistance.
3. Motor control deficit (dynamic knee valgus, trunk drop): exercises with visual and verbal feedback, trunk-hip-knee integration.
4. Hypermobility / stabilisation deficit calls for proprioceptive exercises, controlled loads and avoidance of over-stretching.

The real clinical usefulness of this subclassification is still being validated.²¹ ²² A recent SR (Mansfield 2023, JOSPT NMA) showed that combinations of exercises targeting hip + knee + internal feedback do change weight-bearing kinematic parameters, supporting the idea of rehabilitation guided by the patient's motor profile rather than a standard protocol for everyone.²³

Treatment of PFP is now firmly consensual on its fundamentals. The Gold Coast 2018 consensus (Collins et al.) and the JOSPT 2019 CPG (Willy et al.) converge: patient education and therapeutic exercise are the unavoidable first line, everything else being adjunctive.¹ ²

Where do you start? What is the recommended hierarchy of interventions?

The evidence-based hierarchy, ranked by level of evidence:

The network meta-analysis (NMA) by Winters et al. published in JOSPT in 2022, which included 65 randomised trials, confirms at 3 months that 6 interventions have a positive effect on pain and function: exercise targeting the knee alone, the hip+knee combination, foot orthoses, local manual therapy, exercise combined with perineural dextrose injection, and exercise with quadriceps biofeedback.³ None is dramatically superior to the others in the short term, hence the importance of personalising the choice according to the patient's clinical profile and preferences.

What is the place of exercise and is there a superior approach?

Exercise is the most robustly validated intervention in the literature. The Cochrane review by van der Heijden et al. (2015) had already concluded that there is a moderate effect on pain and function, supported by moderate- to low-quality evidence.⁴ Since then, recent NMAs and SRs/MAs have clarified three key points:

1. Hip + knee > knee alone. The meta-analysis by Nascimento et al. (JOSPT 2018, 14 trials, 673 participants) showed that strengthening hip + quadriceps is superior to strengthening the quadriceps in isolation for reducing pain and improving activity, and this holds even without any detectable increase in strength, which points to neuromuscular and behavioural mechanisms.⁵
2. No superiority of open versus closed chain. The old debates about the “safe angle” (0-45° in CKC, 45-90° in OKC) have been put into perspective: as long as the load stays tolerated and progression is gradual, both modes are effective.² ⁴
3. Load management > the search for perfect movement. The critical review by Lack, Neal and De Oliveira Silva (Phys Ther Sport 2018) reframed the priority: improving the capacity of the tissues to tolerate load through progressive strengthening mattered more than normalising an “ideal” movement pattern that does not exist in the population.⁶

A fundamental point of the 2023 update is that the NMA by Mansfield et al. (JOSPT 2023, 37 trials, n = 1235) established that interventions combining exercise + internal feedback (visual, verbal, mirror) do change frontal-plane kinematics of the knee and hip, which validates the motor-control-centred approach in cases with marked dynamic knee valgus.⁷ Conversely, braces alone and taping alone have no effect on movement kinematics.⁷

Manual therapies and technologies: how effective are they really?

Passive therapies are short-term adjuncts, never the core of treatment.

• Manual therapy (patellar mobilisations, hip mobilisations, lumbopelvic mobilisations) gives short-term pain relief, but no additional long-term benefit when added to a structured exercise programme.² Its role is essentially to reduce initial pain so that the patient can engage in exercise.
• Patellar taping (McConnell) : immediate reduction in pain documented during activity (a probable neurophysiological mechanism). No lasting long-term benefit. Kinesio Taping has not shown superiority over placebo.⁸
• Prefabricated foot orthoses give short-term pain relief in patients with excessive foot pronation shown objectively (peak eversion ≥ 4°), and little effect in the others.² ⁹
• Dry needling rests on emerging and heterogeneous evidence. A few trials show a short-term effect, but recent SRs/MAs remain cautious (poor methodological quality of the studies).¹⁰
• Shockwave, ultrasound, laser : no high-quality evidence supports their use on their own for PFP. The JOSPT 2019 CPG does not recommend them as first line.¹
• Surgery is reserved for failure of a good conservative programme run for at least 6 to 12 months (lateral release, tibial tubercle transfer, MPFL reconstruction where instability is proven).¹ ²

Beyond the physical: how do you educate the patient and address psychological factors?

The education of the patient is an active therapeutic intervention, not a mere add-on. The SR by Pazzinatto, de Oliveira Silva, Barton et al. (JOSPT 2020) showed that structured education (one to several sessions) can improve function and pain for up to 1 year alongside exercise.¹¹ The key themes to cover:

• Demedicalising the pain means explaining that pain does not equal damage, and that an “abnormal” MRI says nothing about the prognosis.
• The load model holds that pain is a signal of overload: the aim is to widen tolerance, not to avoid load.
• Progressive management follows the rule of “no more than 2/10 pain during effort, and it must settle within 24 h”.
• An active role means the patient is the main player and the physiotherapist a coach, not a repairer.

The psychosocial factors are established mediators of symptom persistence. The SR by Maclachlan, Collins, Matthews, Hodges and Vicenzino (BJSM 2017, 25 studies included) confirmed that kinesiophobia, catastrophising, anxiety and depression are high in people with PFP and correlate with severity and function.¹² A more recent SR (Matthews 2022, Phys Ther Sport) reinforces these conclusions and calls for their systematic assessment to be built in.

PFP is the most frequent knee condition in runners, accounting for 16 to 25% of sports medicine consultations depending on the cohort.¹ ² This over-representation justifies a dedicated focus: repetitive mechanics (1,000 to 2,000 strides per kilometre, a load equivalent to 2.5 to 5 × body weight on the kneecap) create specific conditions of cumulative overload.

Which biomechanical alterations are specific to the runner with PFP?

The SR/MA by Neal, Barton, Gallie, O'Halloran and Morrissey (Gait Posture 2016) identified three reproducible kinematic alterations in runners with PFP compared with healthy runners:¹

• ↑ hip adduction (peak hip adduction), a prospective risk factor in women.
• ↑ hip internal rotation (peak hip internal rotation).
• ↑ contralateral pelvic drop (contralateral pelvic drop), a dynamic Trendelenburg.

These three alterations converge on a dynamic knee valgus at initial contact and at mid-stance, increasing mediolateral stresses on the patellofemoral joint.¹ ³ The distal factors (peak rearfoot eversion, rearfoot versus forefoot strike) are also associated, but less consistently.¹

The most important clinical point: these alterations can be modified. The Neal 2016 SR shows that targeted interventions (hip strengthening, gait retraining, feedback) do change running kinematics, which translates into a reduction in pain in trials at 6-12 weeks.¹ ⁴

Gait retraining and increased cadence: how much, and how?

The most robust biomechanical intervention in the runner with PFP is the 5 to 10% increase in cadence (steps per minute).⁴ ⁵ ⁶ The mechanism is mechanical: at a given speed, raising cadence shortens step length, reduces overstriding, lowers peak ground reaction forces and lowers patellofemoral stress by 15 to 20% according to biomechanical models.⁴ ⁵

The randomised trial by Esculier et al. (BJSM 2018, n = 69 runners with PFP) remains the methodological reference. It compared three arms over 8 weeks: education alone, education + exercises, education + gait retraining. All three groups improved pain and function to an equivalent degree, with no superiority for gait retraining on its own. This suggests that education about load management is the mainstay, with gait retraining a useful addition in certain profiles (runners with a low cadence < 170 spm, marked overstriding, pronounced rearfoot strike).⁴

Three main variants of gait retraining for PFP:

1. Increasing cadence (the simplest to implement): aim for +5 to +10% of preferred cadence, using an auditory metronome on a smartphone. Immediate effects on kinematics, variable persistence.⁵
2. Run softer (Davis): sound feedback from an accelerometer to reduce the vertical impact peak. Cuts the incident risk of PFP by around 79% (RR 0.21) according to the Culvenor 2020 BJSM SR/MA.⁷
3. Transition to a midfoot or forefoot strike is controversial. It reduces patellofemoral stress but increases stress on the Achilles tendon and calf, so it should be used cautiously and progressed gradually.⁵ ⁶

For primary prevention, the Neal/Culvenor SR/MA published in BJSM in 2021 (PMID 33115705) remains the reference: across 13 trials and 6 interventions evaluated, only two interventions significantly reduce the incident risk of PFP:⁷

• Patellar braces worn during physical activity: RR 0.40 (95% CI 0.22-0.73), low-quality evidence, a reduction of around 60%.
• Gait retraining (run softer) gives RR 0.21 (95% CI 0.07-0.60), low-quality evidence, a reduction of around 79%.

Conversely, the multicomponent exercise programmes (strengthening / neuromuscular) did not significantly reduce the incident risk of PFP in the 4 included trials (n = 3,364), a surprising result that contrasts with their curative effectiveness. Foot orthoses in primary prevention showed no effect either.⁷ This finding argues for concentrating prevention on load management and technique adjustments rather than on generic exercise protocols.

The success of PFP treatment is not measured at the end of the clinic protocol: it is measured by the patient's ability to manage their load over the years that follow. The prospective data (Hsu 2025) are a reminder that nearly one patient in two remains symptomatic at 5 years without structured management, and that 50-90% of adolescents still have symptoms 1 to 20 years after the initial diagnosis.¹ ²

How do you make the patient an active player in their own recovery through self-management?

The transition to self-management rests on three pillars, ranked by level of evidence:

1. Structured education (an active therapeutic intervention): the SR by de Oliveira Silva, Pazzinatto and Barton (JOSPT 2020) shows that well-delivered education can improve pain and function for up to 1 year.³
2. Home exercise with self-managed progression: the hip + quadriceps combination remains the reference (Nascimento 2018).⁴
3. Load management (training load management): learning the “no more than 10% per week” rule and how to read the pain signal.⁵

The challenge of long-term adherence is the main one. The most effective strategies:

• Collaborative definition of SMART goals by the patient (not by the physiotherapist alone).
• A simple logbook (paper or app) with self-monitoring of pain and load.
• “Booster” sessions scheduled at 3 and 6 months.
• A programme adapted to the patient's real life rhythm (3 sessions of 20 min ≫ a 1-hour programme that never gets done).

When and how do you plan a safe return to sport and activity?

Return to sport (RTS) must be based on functional criteria and not on a fixed timetable.⁶ Unlike ACL reconstruction, there is as yet no standardised, universally validated RTS test battery for PFP: practice rests on expert consensus and clinical judgement.²

The proposed RTS criteria (a synthesis of consensus recommendations):

For runners, the typical progression:

1. Pain-free brisk walking for 30 min ➜ alternating jog-walk (1 min running / 2 min walking) over 20 min.
2. Gradual increase in running duration (1, 2, 3, 5 min and so on) over 4-8 weeks.
3. Gait retraining built in (cadence +5-10%) from the very start of the return.
4. Return to the usual distance before raising the pace again.
5. Progressive reintroduction of specific sessions (hills, intervals, long runs), one variable at a time.

For sports with jumping and changes of direction (basketball, volleyball, football, dance), add a phase of progressive plyometric rehabilitation and a return to sport-specific training before competition.

Analysis of a “classic” case: from assessment to resolution.

The case reported by Khan et al. in Cureus in 2024 illustrates a typical presentation and evidence-based multimodal management.¹ A 21-year-old recreational female runner presented with bilateral anterior knee pain of gradual onset after a rapid increase in running volume. Clinical examination confirmed:

• Bilateral peripatellar pain reproduced on squatting and on descending stairs.
• Documented weakness of the quadriceps and hip abductors.
• Single-leg squat with marked bilateral dynamic knee valgus.
• No red flag, and an otherwise normal joint examination.

Treatment combined the consensus pillars:¹

1. Education covering the load model, demedicalisation, and advice to reduce volume temporarily without stopping altogether.
2. Progressive strengthening with a bilateral hip programme (clams, side-lying abduction, monster walks) + quadriceps (squats, lunges, step-ups), 3 sessions a week over 8 weeks.
3. Motor control work with single-leg squats in front of a mirror and step-downs with verbal feedback.
4. Stretching and mobility targeting the hip flexors and the hamstrings.
5. Progressive return to running with gait retraining (increased cadence) from week 4.

Outcome was a clinically significant improvement in pain (VAS), function (AKPS/Kujala) and running capacity, with a pain-free return by the end of the protocol.¹ This case validates the consensus sequence (education → combined hip+knee exercise → progressive reintegration) and confirms the central place of gait retraining in the runner.

An older but methodologically interesting case, Esculier 2017 in IJSPT (PMC5534157), describes a runner with PFP treated with a multimodal programme addressing kinesiophobia (education + exercises + gait retraining + simple cognitive therapy), with complete resolution in 8 weeks, illustrating the importance of including psychosocial factors from the outset.²

The diagnostic challenge: when PFP mimics another condition.

The entrapment of the infrapatellar branch of the saphenous nerve (IPBSN) is a classic differential diagnosis of PFP. A recent case published in Cureus in 2025 (PMC12558126) is exemplary:³

• Presentation was anterior knee pain “of the PFP type” resistant to several months of standard conservative rehabilitation.
• Discriminating feature on palpation, exquisite tenderness at the site where the nerve pierces sartorius, with neuropathic radiation.
• Targeted imaging with high-resolution ultrasound confirming IPBSN entrapment at the level of sartorius.
• Treatment with ultrasound-guided manual mobilisation of sartorius, saphenous neurodynamics, followed by soft tissue techniques.
• Outcome was complete resolution of the pain within a few sessions.

The clinical message is clear: any PFP that does not respond to well-conducted conservative treatment after 6-8 weeks should prompt a rethink of the diagnosis. The classic traps:

• IPBSN neuralgia (Trescot 2013, Cureus 2025): band-like pain, pinpoint tenderness, often after arthroscopy.
• Medial synovial plica syndrome (Schindler 2014): snapping, mediopatellar pain, sometimes resistant.⁴ The full picture and the real value of the tests are detailed in the dedicated article.
• Patellar tendinopathy gives very focal pain at the inferior pole of the kneecap, aggravated by jumping.
• Hoffa syndrome gives pain on either side of the patellar tendon, increased by forced extension.
• Early patellofemoral osteoarthritis occurs in an older patient, with morning stiffness and audible crepitus.

Study of a complex case (hypermobility, kinesiophobia).

Two clinical situations call for a significant adaptation of the standard strategy.

Case no. 1: generalised hypermobility / hypermobile Ehlers-Danlos syndrome. Hypermobile patients are at increased risk of PFP (with or without associated patellar instability). The data from Ferrero et al. (2025) on the risk factors for patellofemoral instability in patients with hEDS underline that classic heavy-load rehabilitation may be poorly tolerated.⁵ For the current nomenclature, the limits of the Beighton score and exercise dosage in this population, see joint hypermobility syndromes. The approach must be adapted:

• Strengthening below threshold initially, with light loads and very slow progression.
• Priority emphasis on motor control and proprioception rather than pure strength.
• Work on eccentric control within limited ranges.
• Monitoring for patellar subluxation, with referral for MPFL surgery if instability is proven and disabling.
• A reinforced biopsychosocial approach (frequent chronic pain, fatigue, comorbidities).

Case no. 2: kinesiophobia / catastrophising. The case published by Carter et al. in American Journal of Case Reports in 2021 (PMC8378777) illustrates the integration of pain neuroscience education (PNE) in a patient with multi-region chronic pain (lumbopelvic, cervical, knee).⁶ The intervention combined:

• 7 sessions of structured PNE over 4 weeks (videos, metaphors, drawings, discussion).
• Manual therapy + exercises prescribed by the qualified physiotherapist.
• Graded exposure to feared movements.

Results: a clinically significant decrease in subjective pain and in kinesiophobia (Tampa Scale for Kinesiophobia), even though the reduction in fear-avoidance and perceived disability was more modest.⁶ This case supports the place of PNE in chronic PFP with a strong psychosocial component, alongside the physical programme.

When, and to which other health professionals, should you refer?

Referral is not an admission of failure but a clinical skill. Three main situations:

1. Red flags → urgent medical referral. The international Finucane 2020 framework (JOSPT) remains the reference for detecting serious pathology.¹ For PFP and anterior knee pain, remember:

• Acute trauma with inability to bear weight or haemarthrosis → orthopaedics / emergency department.
• Persistent effusion, local warmth, fever → suspected infection or inflammation.
• True joint locking, repeated giving way → suspected meniscal / osteochondral lesion.
• Mechanical night pain, weight loss, history of cancer → work-up for tumour.
• Progressive neurological deficits → spinal work-up.

2. Yellow flags → psychological collaboration. Severe kinesiophobia (Tampa Scale ≥ 37), marked catastrophising, major anxiety or depression, low self-efficacy: the Maclachlan 2017 SR confirms their impact on persistence.² A “psychologically informed” physiotherapy approach (PIPT) is useful as a first step; the most severe cases warrant referral to a psychologist or psychiatrist alongside physical rehabilitation.

3. Failure of conservative treatment → orthopaedics / sports medicine. After 3-6 months of a well-conducted conservative programme (documented adherence, genuine progression) without significant improvement, a surgical opinion may be considered to discuss targeted options (lateral release, tibial tubercle transfer, MPFL reconstruction where there is instability). Surgery remains a last resort.¹ ³

How do you measure outcomes and overcome the barriers to implementation?

The systematic use of validated Patient-Reported Outcome Measures (PROMs) is fundamental for assessing progress objectively and guiding clinical decisions. For PFP, the recommended tools (JOSPT 2019 CPG, Manchester 2016 consensus):³ ⁴

• Anterior Knee Pain Scale (AKPS / Kujala) has 13 items, a score of 0-100 and an MCID of ≈ 8-10 points. The historical reference, sensitive to change.
• KOOS-PF (Knee Injury and Osteoarthritis Outcome Score - Patellofemoral subscale) is a patellofemoral-specific subscale, 11 items, sensitive to clinical change.
• Visual analogue scale (VAS) records pain during different activities (rest, stairs, running), MCID ≈ 1.5-2 cm.
• Lower Extremity Functional Scale (LEFS) has 20 items, applies to any lower limb condition, MCID ≈ 9 points.
• Tampa Scale for Kinesiophobia (TSK) or Fear-Avoidance Beliefs Questionnaire (FABQ) for systematic assessment of fear of movement.
• Global Rating of Change (GRC) a subjective measure of overall improvement on 7 or 15 points.

Overcoming the barriers to implementation :

• Lack of time ➜ Build short PROMs (AKPS, VAS, GRC) into the initial assessment session and every 4-6 sessions. Use pre-filled paper questionnaires in the waiting room, or digital tools.
• Continuing education ➜ Follow the recent SRs/MAs (a PubMed alert on “patellofemoral pain”), training in biopsychosocial models, practical gait retraining sessions.
• Shared decision-making ➜ Present the options and their levels of evidence, take the patient's preferences into account, build the goals together.
• Professional network ➜ Identify your contacts in advance (sports physician, orthopaedic surgeon, psychologist, podiatrist) to make referrals easier.
• Updating protocols ➜ Revise the in-house protocol with every major new SR/MA (Mansfield 2023, Hsu 2025, and so on).