Patellofemoral Pain Syndrome (PFPS) is a broad term used to describe pain felt around the kneecap (patella) or the surrounding tissues at the front of the knee. It is commonly called runner’s knee because it is frequent in runners, but PFPS can also affect people who do gym training, team sports, hiking, dancing, manual work, or even people whose main trigger is simply stairs or prolonged sitting.
PFPS usually develops gradually. Many people notice a dull ache at the front of the knee that slowly intensifies over time, especially with activities that load the knee in a bent position. Common aggravating activities include squatting, lunging, going up and down stairs, jumping, and running (particularly downhill or hills). Many people also report discomfort after sustained sitting, such as at the movies, on an airplane, or in school. This is sometimes called the “movie sign”.
Even though PFPS is often described as a kneecap problem, it is rarely caused by just one structure. In most people, it is best understood as a load-related pain condition. The patellofemoral joint is the contact area between the kneecap and the femur (thigh bone). When you squat, climb stairs, or run, the forces through this joint increase. If the load you place on the knee becomes greater than what your tissues can currently tolerate, pain can develop.
This is where physiotherapy for patellofemoral pain syndrome is so important. PFPS is not usually fixed by rest alone. Rest may reduce symptoms temporarily, but pain often returns when you go back to running, stairs, or training if strength and movement control have not improved. A physiotherapist can identify why your knee is being overloaded, help you modify irritating activity without stopping everything, and build a targeted strengthening and movement retraining program so your knee becomes more resilient.
PFPS can be frustrating because scans often do not show a clear “injury”. That does not mean the pain is imagined. It means the issue is often more about how the knee is being loaded and how the muscles around the hip, thigh, and calf are sharing the work. With the right plan, most people can get back to running, sport, gym, and everyday life with significantly less pain and more confidence.
Key Facts
- Patellofemoral pain syndrome (PFPS) is a broad diagnosis describing pain around or behind the kneecap, commonly triggered by squatting, stairs, running and prolonged sitting. 🔗
- PFPS usually starts gradually and is strongly linked to knee loading in a bent position, which is why it is often called runner’s knee. 🔗
- PFPS is typically managed conservatively, with physiotherapy and exercise therapy as the first-line treatment for most people. 🔗
- Strength deficits at the hip and thigh, reduced calf capacity, and poor movement control can increase stress through the patellofemoral joint. 🔗
- Foot pronation and lower limb alignment can contribute in some people, which is why foot orthotics are sometimes used for short-term symptom relief. 🔗
- Taping and education (including load management) can provide short-to-intermediate symptom relief, but long-term improvement requires progressive strengthening and graded return to activity. 🔗
Risk Factors
- Sudden increase in running distance, speed work, hill running, or training frequency.
- Participation in sports with repeated knee bending and landing (netball, basketball, football codes, dance).
- Reduced hip strength endurance (gluteal weakness) leading to inward knee drift during fatigue.
- Reduced quadriceps strength or poor thigh muscle control during squats, stairs and running.
- Reduced calf capacity or ankle mobility limitations that shift load toward the knee.
- Foot pronation (flatter feet) or rapid footwear changes that alter lower limb mechanics.
- Training on hard surfaces or lots of downhill running without adequate conditioning.
Symptoms
- Dull ache at the front of the knee, around or behind the kneecap.
- Pain that develops gradually and slowly intensifies over weeks to months.
- Pain during or after activities that repeatedly bend the knee, such as running, jumping, squatting, or gym training.
- Pain going up or down stairs, especially descending.
- Pain after prolonged sitting (movies, airplane travel, school, office work) then pain when standing and walking.
- Cracking, popping or grinding sensations when getting up from a chair or climbing stairs.
- Symptoms can be present in one knee or both knees.
- Pain often improves as you warm up, but can worsen later that day or the next morning if you overloaded the knee.
Aggravating Factors
- Squatting, lunging and deep knee bending (including leg press and heavy gym work).
- Stairs and hills, especially going downhill or descending stairs.
- Running, particularly hills, speed work, sudden increases in distance or frequency, and hard surfaces.
- Jumping and landing tasks (netball, basketball, volleyball, HIIT classes).
- Prolonged sitting with the knee bent, then standing up (the “movie sign”).
- Kneeling or prolonged positions that compress the front of the knee in some people.
Causes
Patellofemoral pain syndrome (PFPS) usually develops when the front of the knee is exposed to more load than it can tolerate, especially during repeated bending activities like running, stairs, squatting, and jumping. The patellofemoral joint naturally experiences higher forces as the knee bends, but symptoms tend to occur when that load is too high, too frequent, or not well shared through the hip, thigh, and ankle. PFPS is most often an overload condition, rather than the result of a single injury, and is usually influenced by a combination of factors rather than one clear cause.
Common contributing factors include:
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Rapid increases in training or activity (the most common trigger), such as increasing running volume, hills, speed work, starting a new sport season, or adding gym exercises like squats and lunges.
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Reduced strength or endurance, particularly in the quadriceps and hip muscles, which can reduce control and increase stress around the kneecap during running, stepping down, or landing.
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Movement patterns, such as the knee drifting inward during squats, single-leg tasks, or running, which may increase stress at the patellofemoral joint for some people.
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Ankle mobility and calf capacity, because stiff ankles or weaker calves can reduce shock absorption and shift more load up to the knee during running and squatting.
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Foot posture and footwear changes, where increased pronation or sudden changes in shoes (minimalist/low-drop/barefoot exposure) can alter how load is distributed through the lower limb and contribute to symptoms.
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Patellar tracking differences, where the kneecap may sit or move slightly differently (often more lateral), which is common and not always painful—but can become relevant when combined with load spikes and reduced capacity.
The key takeaway is that PFPS is usually multifactorial, which is why physiotherapy is so effective: rehab focuses on identifying your personal triggers, settling irritability without complete rest, building strength and control through the whole leg, and gradually returning you to the activities that matter to you.
How Is It Diagnosed?
PFPS is diagnosed through a combination of your symptoms, your activity history, and a physical assessment. A physiotherapist will usually diagnose patellofemoral pain syndrome by identifying a consistent pattern of:
1) Pain location: pain around or behind the kneecap, often described as a dull ache at the front of the knee.
2) Load-related triggers: pain aggravated by squatting, stairs, running, jumping, prolonged sitting, or gym movements that repeatedly bend the knee.
3) Gradual onset: symptoms commonly build over time rather than starting from a single traumatic event.
During the physical exam, your physiotherapist will assess knee range of motion, quadriceps strength and control, hip strength, calf strength, ankle mobility, and movement quality during tasks like step-downs, squats and single-leg control. They may also assess running mechanics if running is a goal. The aim is to identify why your knee is being overloaded and which physical qualities need to improve for long-term relief.
A key part of diagnosis is also ruling out other causes of anterior knee pain such as patellar tendinopathy, fat pad irritation, significant knee swelling from other injuries, or referred pain from the hip or back. If your presentation is atypical (for example significant swelling, true locking, major trauma, or night pain), your physiotherapist may recommend GP review and imaging to exclude other causes.
Investigations & Imaging
- X-ray (plain radiograph)
- Not routinely needed for PFPS. May be used if symptoms are persistent, there is a history of trauma, or to assess for arthritis or other bony issues when clinically indicated.
- MRI (Magnetic Resonance Imaging)
- May be considered if symptoms are not improving with appropriate physiotherapy, if there is significant swelling, instability, locking, or concern about other joint structures.
- Ultrasound
- Not commonly used to diagnose PFPS. May be used if patellar tendon pain is suspected or to assess superficial soft tissue structures when clinically appropriate.
Physiotherapy Management
Physiotherapy for patellofemoral pain syndrome is highly effective for most people because PFPS is commonly driven by modifiable factors: strength deficits, poor load tolerance, and movement patterns that overload the kneecap area. A physiotherapist will build a plan that reduces symptoms in the short term and improves resilience in the long term.
PFPS rehab is not just a list of generic exercises. It is a staged program that usually includes:
1) Load management to reduce flare-ups while you keep active.
2) Targeted strengthening of hip, quadriceps and calf to reduce knee stress and build capacity.
3) Movement retraining for stairs, squats, running and landing, based on your goals.
4) Return to running or sport planning so you do not relapse when you increase training.
Most people start to notice improvements when they combine consistent rehab with smart training decisions, rather than trying to push through pain or resting for weeks and then returning suddenly.
Exercise
PFPS physiotherapy exercises are designed to reduce stress through the patellofemoral joint by improving how the whole lower limb shares load. In many people, early hip strengthening helps reduce symptoms because it improves pelvic and thigh control, which can decrease knee overload during daily activities and sport.
Hip strengthening: Your physiotherapist will often start with hip abductor and external rotator strengthening (gluteal exercises). These may begin with low-irritability drills like side-lying work or band-based exercises and progress to functional single-leg work like step-downs and split squats with excellent alignment. The goal is not just strength, but endurance and timing so control holds up when you are fatigued.
Quadriceps strengthening: Strong quadriceps help control knee bend and improve tolerance to stairs and squatting. Rehab usually progresses from tolerable ranges (for example partial range sit-to-stands) to deeper squats, step-ups, and gym-based strengthening such as leg press variations. Your physio will adjust range of motion, tempo, and load to make sure you are building capacity without constantly flaring pain.
Calf strengthening: Calf function is crucial in running and jumping. Weak calves can increase load transfer to the knee. Many PFPS programs include calf raises (straight-knee and bent-knee variations), progressing to higher endurance and eventually plyometric preparation if you want to run or jump pain-free.
Proprioception and control: Balance and control exercises teach your body to manage load efficiently. These often include single-leg balance, controlled step-downs, and coordination drills that mimic your sport or daily tasks.
PFPS rehab progression: As pain improves, your physiotherapist will build toward strength, power, and higher-level function. For athletes, this means gradually reintroducing plyometrics, faster direction changes, and running progressions in a planned way, rather than jumping straight back into hills and speed work.
Key idea: In PFPS, the best exercise program is the one that matches your current irritability and goals. Doing the “right” exercises at the wrong intensity or volume can still flare pain. Regular physio review helps ensure you are progressing at the right pace.
Activity Modification
Activity modification is a cornerstone of PFPS management because symptoms are often driven by overload. The aim is not to stop everything. The aim is to temporarily reduce the activities that spike pain, while continuing safe activity and building capacity through rehab.
Examples of helpful modifications include reducing hill running, reducing downhill exposure, choosing flatter routes, cutting back on deep squats and heavy lunges temporarily, breaking long stair bouts into smaller chunks, or using the lift for a short period if stairs are very flared.
For runners, a physiotherapist may guide you to find a pain-tolerable running dose (distance, pace, frequency) and build from there. They may also discuss cadence adjustments (slightly increasing step rate) or foot-strike considerations depending on your mechanics and symptoms. The key is consistency and gradual progression.
For gym training, modifications might include changing squat depth, slowing tempo, adjusting stance, changing exercise selection, or splitting volume across the week. This allows you to keep strengthening without constantly provoking the kneecap area.
Manual Therapy
Manual therapy can be useful for some people with PFPS, particularly when pain has led to muscle tightness and movement restriction that makes exercise difficult. A physiotherapist may use soft tissue techniques for quadriceps, hip flexors, calves, or lateral thigh region, and may use gentle joint mobilisation if there are restrictions affecting movement patterns.
Manual therapy is typically a support strategy. It can reduce discomfort and improve confidence so you can perform your strengthening and movement retraining program more effectively. Long-term improvement still depends on building strength, control, and load tolerance.
Postural Retraining
Postural and movement retraining in PFPS targets the positions and habits that increase kneecap stress. Many people with runner’s knee collapse inward at the knee when stepping down, squat with poor control, or run with mechanics that overload the front of the knee, especially when fatigued.
Your physiotherapist may retrain:
Stair and step-down technique so the knee tracks smoothly and load is shared through the hip.
Squat and lunge form to improve control and reduce pain sensitivity while still building strength.
Running mechanics such as cadence, stride control, trunk posture, and hip control, particularly if running is your main trigger.
This retraining is highly individual. Two people with PFPS can have different movement patterns, so the best approach is guided by assessment rather than generic cues.
Bracing & Taping
Taping and bracing can help reduce pain in the short to intermediate term for some people with PFPS. A common approach is patellofemoral taping (often referred to as McConnell-style taping) which aims to change patella position and improve comfort during aggravating activities such as stairs, squatting, or running.
Taping is typically used as a short-term symptom modifier. If it helps you exercise with less pain and better mechanics, it can be a valuable tool during early rehab. The long-term goal is to reduce reliance on tape by improving strength and movement control so the knee stays comfortable without external support.
Dry Needling
Dry needling may help by reducing muscle tension and pain sensitivity around the hip and thigh (especially the quadriceps), which can improve comfort and movement so you can load the knee more effectively during rehab.
Heat & Ice
Heat and ice can be used for short-term symptom relief. Some people find ice helps after activity when the knee feels hot or irritated, and heat can help with general stiffness before exercise. These strategies are optional and should support your ability to stay active and complete rehab.
If your pain is escalating and you need ice after every session, it often indicates that your training load is still too high for current capacity. A physiotherapist can help adjust your plan so symptoms trend down rather than continually spiking.
Education
Education is a key part of PFPS physiotherapy. Many people are told to “strengthen your VMO” or “your kneecap is out of place”, which can be confusing and unhelpful. A physiotherapist will explain PFPS in a practical way: your knee is sensitive to certain loads right now, and your plan is to reduce irritability while building capacity.
Education commonly includes:
Load management principles: how to keep activity within tolerable limits and avoid boom-bust cycles.
Flare-up management: how to modify training for a few days if symptoms spike, rather than stopping completely.
Progression planning: how and when to reintroduce hills, stairs volume, deeper squats, or plyometrics.
Self-management strategies: warm-up routines, pacing long sitting periods, and strategies for work or school environments.
Strong education helps you feel in control of recovery, which is often the difference between recurring PFPS and long-term success.
Other
Foot orthotics: Orthotics may be used for some people with PFPS, particularly if increased foot pronation is contributing to inward knee movement and symptoms. Orthotics are generally considered a short-term pain reducer rather than a long-term cure. They can be useful if they allow you to keep walking or running comfortably while you build strength and control through physiotherapy.
Footwear advice: Sometimes simple changes like replacing worn shoes, avoiding sudden shifts to minimalist footwear, or selecting shoes that suit your training load can help reduce symptom spikes.
Return-to-running programming: For runners, a structured progression that increases distance, speed and hills gradually is often essential to avoid relapse. A physiotherapist can tailor this based on your symptoms and training schedule.
Other Treatments
Medication: Simple pain relief may be used short-term under guidance from your GP or pharmacist. Medication can help you stay active and participate in rehab, but it should not be used to push through pain while the knee is overloaded.
Education and load management: For many people, this is the most effective “treatment” in the early phase. Small changes to running hills, stairs exposure, and gym depth can reduce pain quickly while you build strength.
Cross-training: Maintaining fitness with options such as cycling, swimming, or upper-body conditioning can be valuable when running or jumping temporarily needs to be reduced.
Work and lifestyle modifications: People who flare with long sitting may benefit from regular movement breaks, changing seat height, or adjusting daily stair exposure while symptoms settle.
Surgery
Surgery is rarely required for Patellofemoral Pain Syndrome. PFPS is usually managed successfully with conservative treatment, particularly a structured physiotherapy program focused on strengthening, movement retraining, and gradual return to activity.
In uncommon cases where pain is persistent, severe, and not improving after a thorough rehab plan, a specialist may consider further investigation to check for other contributing pathology. If structural issues such as significant instability, recurrent dislocation, or clear surgical pathology are present, surgical options may be discussed. However, these situations are typically different diagnoses than straightforward PFPS.
Even if a surgical pathway is ever considered, physiotherapy remains essential before and after any intervention to restore strength, control, and long-term knee tolerance.
Prognosis & Return to Activity
The prognosis for PFPS is generally good with appropriate management. Many people experience meaningful improvement within weeks to months when they commit to a structured strengthening program and manage load intelligently. However, PFPS can become persistent if people keep repeating the same overload pattern, such as repeatedly increasing running volume too quickly, pushing through stair pain daily, or returning to deep squats at high volume before strength has improved.
Return to running and sport should be guided by capacity, not just short-term pain reduction. Your physiotherapist will typically look for:
- Symptom stability: pain is low and does not spike the next day after training.
- Strength improvements: better hip, quadriceps and calf strength endurance, often reflected in improved stair and squat tolerance.
- Movement quality: improved single-leg control and better mechanics during sport tasks.
- Gradual exposure: ability to reintroduce hills, speed, jumping or deeper knee bend without flare-ups.
Many runners with PFPS can return successfully when they follow a graded plan and avoid sudden jumps in distance, hills, and speed work all at once. Athletes in jumping sports often need a staged progression into plyometrics and repeated effort conditioning so the knee is stable under fatigue.
Complications
- Persistent pain with stairs, squats and running if the underlying strength and load tolerance deficits are not addressed.
- Reduced participation in sport or fitness due to fear of pain, leading to deconditioning and ongoing sensitivity.
- Compensation patterns such as altered gait, hip or calf overload, or secondary pain due to avoidance of knee loading.
- Recurrent flare-ups (boom-bust cycle) when activity is repeatedly stopped, then restarted with too much intensity too quickly.
Preventing Recurrence
- Increase running volume, hills and speed gradually. Avoid changing distance, intensity and terrain all at once to prevent PFPS flare-ups.
- Maintain hip and quadriceps strength year-round. Stronger hips and thighs reduce stress around the kneecap during stairs, squats and running.
- Keep calf strength and ankle mobility in your program, especially if you are a runner, as this helps share load away from the knee.
- Use a warm-up that includes single-leg control and gradual knee bending before training to reduce pain sensitivity and improve movement quality.
- Manage prolonged sitting triggers by taking short standing or walking breaks, and avoid jumping straight into stairs after long sitting when flared.
- If you have flatter feet and PFPS, consider short-term orthotics or footwear changes while building strength and control, rather than relying on orthotics alone.
When to See a Physio
- You have front-of-knee pain that is limiting stairs, squats, running, or sport.
- Pain has been present for more than 2 to 4 weeks and is not improving with basic rest or activity reduction.
- You have recurring PFPS flare-ups whenever you try to return to running, hills, or gym exercises.
- You feel knee weakness, poor control, or apprehension with single-leg tasks like step-downs, jumping or cutting.
- You want a structured return-to-running plan and PFPS physiotherapy exercises matched to your goals.
- You have swelling, locking, instability, or a traumatic injury event (these features need assessment to rule out other conditions).