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Health condition · Clinically reviewed

Anterior knee pain, the runner\'s knee story - and how modern rehab fixes most of it.

Patellofemoral pain syndrome is the commonest cause of anterior knee pain in active people. A hip-led, load-aware rehabilitation plan beats rest, gadgets and early surgery.

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A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, BOA, BASEM and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including load management, hip-led rehabilitation and staged escalation for refractory cases.

Key facts

Anterior knee pain at a glance.

The essentials in plain English: what PFPS is, who it affects, what drives it and how it is treated in the UK today.

  • What it is

    Anterior knee pain from the patellofemoral joint, often called runner's knee, driven by patellar maltracking and load intolerance rather than any single structural lesion.

  • Who gets it

    Common in young athletic adults and adolescents, especially runners, jumpers and cyclists. Often bilateral. Women affected more than men.

  • Classic story

    Pain going down stairs, after prolonged sitting (the movie sign), with squatting, hill running and kneeling.

  • Underlying drivers

    VMO weakness, hip abductor weakness, increased Q-angle, femoral anteversion, foot pronation and rapid training load increases.

  • Foundation therapy

    Structured physiotherapy focused on hip and quadriceps strength, load management and gait or footwear correction. Not rest alone.

  • Surgery

    A last resort. Reserved for confirmed structural problems such as recurrent dislocation, cartilage lesion or isolated patellofemoral OA.

Why this guide matters

A rehabilitation plan, not a scan and a scalpel.

PFPS is often treated with rest, imaging and injections that were never needed. The three points below shape everything else on this page.

  • It is a load and control problem

    PFPS usually reflects load intolerance and poor hip and knee control, not a structural injury that needs a scan first.

  • Hip work matters as much as knee work

    Hip abductor and external rotator strength changes how the kneecap tracks. Neglecting the hip is the commonest reason rehab fails.

  • Surgery is a last resort

    Operations are reserved for confirmed structural problems - recurrent dislocation, maltracking, cartilage lesions or isolated PFJ OA.

How the diagnosis is made

From first flare to a clear plan.

The steps a UK GP, sports physician or physiotherapist will normally follow, in order, so you know what to expect and why.

  1. 01

    Assessing

    History and load review

    Onset, activities, recent training changes, stairs pain, movie sign, kneeling and squatting. A rapid rise in running or jumping load is a strong clue.

  2. 02

    Assessing

    Structured knee examination

    Q-angle, VMO bulk, patellar glide and tilt, tenderness of the medial and lateral facets, Clarke test and patellar apprehension test.

  3. 03

    Assessing

    Hip, foot and gait assessment

    Hip abductor strength, single-leg squat control, dynamic pronation and running gait. PFPS is rarely just a knee problem.

  4. 04

    Confirming

    Rule out mimics

    Distinguish from patellar or quadriceps tendinopathy, plica, Hoffa's fat pad impingement, prepatellar bursitis, meniscus tear and ITB syndrome.

  5. 05

    Confirming

    Imaging when indicated

    X-ray Merchant view for maltracking; MRI selectively to exclude OCD, patellofemoral OA or a chondral lesion in refractory or atypical cases.

  6. 06

    Planning

    Referred pain screen

    Consider referred pain from a hip labral tear or the lumbar spine, particularly when the knee exam is unremarkable.

  7. 07

    Planning

    Rehabilitation plan

    Agree a staged programme with a physiotherapist, with clear load targets and review points at six and twelve weeks.

Typical timeline: a first appointment to a settled programme in a fortnight, with review at six and twelve weeks.

Distinguish from

What else can look like PFPS.

Anterior knee pain has a long differential. A careful examination usually sorts it - imaging only when the story does not fit.

  • Patellofemoral OA

    Older adults with crepitus, morning stiffness and X-ray changes. Overlaps with PFPS but management shifts toward osteoarthritis programmes.

  • Patellar tendinopathy

    Jumper's knee. Focal pain at the inferior pole of the patella, worse with landing and change of direction.

  • Quadriceps tendinopathy

    Focal pain at the superior pole of the patella, common in older lifters and jumpers.

  • Chondromalacia patellae

    Cartilage softening on the undersurface of the patella - graded arthroscopically. Often overlaps with PFPS but a distinct label.

  • Plica syndrome

    Medial synovial band irritation. Snapping and localised medial pain, sometimes reproducible with a specific manoeuvre.

  • Hoffa's fat pad impingement

    Pain behind the patellar tendon with hyperextension. Common after direct blows and in hypermobile athletes.

  • Prepatellar bursitis

    Housemaid's knee. Visible swelling in front of the patella from kneeling occupations.

  • Meniscus tear

    Joint-line pain, catching or locking, often with a twisting injury. MRI helps when locking is present.

  • ITB syndrome

    Lateral knee pain in runners, not anterior. Worse with downhill running and repetitive knee flexion.

  • Osteochondritis dissecans

    Adolescents and young adults with focal deep pain and sometimes a joint effusion. MRI is diagnostic.

  • Referred hip labral tear

    Groin or anterior thigh pain that presents as anterior knee pain. Always screen the hip.

  • Lumbar referred pain

    Anterior knee pain can be an L3 or L4 radiculopathy. Screen the back when the knee exam is unremarkable.

Symptoms

What PFPS actually feels like.

The classic mix of stair pain, movie sign and load intolerance - and the features that mean it is time to look harder.

  • Anterior knee pain

    Diffuse pain around or behind the kneecap, often hard to point to with one finger. Usually gradual in onset.

  • Worse going down stairs

    Descending stairs, hills or slopes loads the patellofemoral joint most. A very typical PFPS story.

  • Movie sign

    Aching after long periods of sitting with the knee bent, easing when you stand and move.

  • Squatting and kneeling pain

    Deep squats, lunges and kneeling reproduce the pain. Often a limit to gym and daily activities.

  • Often bilateral

    Both knees are affected in a large proportion of people, though one side is usually worse.

  • Crepitus and grinding

    A grating or clicking sensation behind the kneecap is common and usually harmless on its own.

  • Giving way or catching

    Buckling can occur from pain inhibition, but true locking should prompt a look for meniscus or cartilage causes.

  • Red flag - true instability

    Recurrent frank dislocation, a large effusion or trauma-related pain deserves urgent orthopaedic review.

Treatment

How PFPS is treated in the UK.

Rehabilitation and load management first, adjuncts like taping, bracing and orthotics next, targeted injections for refractory cases, and surgery only for confirmed structural problems.

  • Structured physiotherapy

    The cornerstone. Hip abductor and VMO strengthening, foot posture work, gait retraining and graded load management over 8 to 12 weeks.

  • Load management

    Temporarily reduce aggravating activities such as hill running, deep squats and stairs. Rebuild gradually rather than stopping altogether.

  • Taping

    McConnell or Kinesio taping can give modest short-term pain relief and help people engage with rehabilitation. Evidence is modest.

  • Patellofemoral bracing

    A patellar tracking brace or sleeve can be helpful during return to sport, particularly in adolescents and jumpers.

  • Foot orthotics

    Considered if there is significant dynamic pronation. Off-the-shelf orthotics are a reasonable first trial before custom devices.

  • Short-course NSAIDs and ice

    Useful for flare-ups. Not a long-term strategy and does not replace the underlying rehabilitation work.

  • Targeted injections

    For refractory cases, a Hoffa's fat pad or patellofemoral joint injection may be considered. Hyaluronic acid is off-label at the PFJ.

  • Surgery, last resort

    Reserved for structural problems: MPFL reconstruction for recurrent dislocation, tibial tubercle transfer for maltracking, or joint-preserving cartilage work.

Surgery in detail

Operations are reserved for a small minority.

  • Lateral release for confirmed lateral patellar compression syndrome, used more selectively than in the past.
  • MPFL reconstruction for recurrent patellar dislocation, restoring the medial patellofemoral ligament.
  • Tibial tubercle transfer for significant maltracking with a raised TT-TG distance.
  • MACI or microfracture for a focal cartilage lesion, discussed in our MACI cartilage repair guide.
  • Patellofemoral arthroplasty for isolated PFJ osteoarthritis in a younger patient where a full knee replacement would be over-treatment.

What this guide is based on

The sources behind every claim on this page.

UK national guidance, specialist society standards and international consensus current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP, physiotherapist or knee surgeon knows your history and examination and can tell you which parts apply to you. If in doubt, get seen.

  • NICE Clinical Knowledge Summary. Knee pain - assessment.

  • British Orthopaedic Association (BOA). Standards for the management of patellofemoral disorders.

  • British Association of Sport and Exercise Medicine (BASEM) consensus statements on patellofemoral pain.

  • Collins NJ et al. 2018 Consensus statement on exercise therapy and physical interventions for patellofemoral pain (British Journal of Sports Medicine).

Red flags

When anterior knee pain needs a closer look.

Most PFPS is manageable in primary and community care. These are the situations that are not - and where a specialist opinion is needed.

  • Recurrent patellar dislocation

    Frank dislocations of the kneecap point to structural instability. An orthopaedic opinion and dedicated imaging are needed, often with MPFL reconstruction discussion.

  • True mechanical locking

    A knee that will not fully straighten suggests a meniscus tear or loose body rather than PFPS. Needs prompt assessment.

  • Significant swelling or effusion

    PFPS usually has little or no effusion. A tense or recurrent effusion points elsewhere and warrants imaging.

  • Night pain or systemic symptoms

    Pain waking the patient, fevers, weight loss or a hot swollen joint needs same-day review to exclude sepsis or serious pathology.

  • Adolescent with focal bony pain

    Focal, well-localised pain in a growing knee raises concern for osteochondritis dissecans or, rarely, tumour. Imaging is prompted early.

  • Post-traumatic anterior knee pain

    A dashboard injury or fall on the knee needs assessment to exclude patellar fracture, chondral injury or MPFL rupture.

  • Refractory pain despite good rehab

    Failure to improve after a properly delivered 12-week programme is itself a red flag for a missed diagnosis, not a reason to try harder rest.

  • Referred hip or spine pain

    Anterior knee pain can be the presenting symptom of a hip labral tear, hip OA or lumbar radiculopathy. Screen the hip and back in every case.

Living with it

A treatable condition, with a clear ladder.

Four things that make the biggest difference day to day - patience with strength work, sensible load modification, training the hip as well as the knee, and knowing when to escalate.

A quiet reminder

Consistency beats intensity, every time.

Small, steady habits kept up for months do more for a knee than a heroic week that does not last.

  1. 01 Patience

    Give rehab 8 to 12 weeks

    Strength changes are slow. Judge progress at three months, not three sessions, and keep going even when a good week is followed by a flare.

  2. 02 Load

    Modify, do not stop

    Total rest usually makes PFPS worse. Swap hills and stairs for flatter routes, cycle in an easier gear and rebuild volume gradually.

  3. 03 Hips

    Train the hip, not just the knee

    Hip abductor and external rotator strength changes how the kneecap tracks. Side-lying and standing hip work is often the missing piece.

  4. 04 Escalate

    Know when to ask for more

    If a structured programme has not helped after three months, ask for a specialist review rather than living around the pain.

Frequently asked

Everything we get asked about PFPS.

Quick answers on rehabilitation, imaging, running and when surgery fits.

  • What is patellofemoral pain syndrome?

    A common cause of anterior knee pain from the joint between the kneecap (patella) and the thigh bone (femur). It is driven by patellar maltracking, muscle weakness around the hip and knee, and load intolerance, rather than by any single structural injury. It is often called runner's knee.

  • Why does it hurt going down stairs and after sitting?

    Descending stairs and hills loads the patellofemoral joint more than going up. Sitting with the knee bent for long periods, the movie sign, keeps the kneecap pressed against the femur and irritates sensitive tissues, so the first few steps feel stiff and sore.

  • Do I need an MRI or X-ray?

    Not routinely. Most PFPS is diagnosed on history and examination. An X-ray, including a Merchant view, is used if maltracking or arthritis is suspected. MRI is reserved for refractory cases or where osteochondritis dissecans, patellofemoral OA or a chondral lesion needs to be excluded.

  • What is the most effective treatment?

    Structured physiotherapy focused on hip abductor and quadriceps strengthening, load management, and gait or footwear correction. Taping, bracing and orthotics can help in specific situations. Injections and surgery are reserved for a small minority with clear structural problems.

  • Should I stop running?

    Usually not. Complete rest tends to make PFPS worse. Most people do better by reducing volume, avoiding hills for a while, switching some sessions to flatter routes or cycling, and rebuilding load gradually alongside a strength programme.

  • When is surgery considered?

    Surgery is a last resort. It is considered for confirmed problems such as recurrent patellar dislocation (MPFL reconstruction), significant maltracking (tibial tubercle transfer), focal cartilage lesions (microfracture or MACI) or isolated patellofemoral OA in a young patient (patellofemoral arthroplasty).

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