What Is Patellofemoral Pain Syndrome?

The patellofemoral joint is formed by the patella and femoral trochlea.

During knee flexion and extension, the patella moves within the trochlea while transmitting forces generated by the quadriceps mechanism.

Activities requiring greater knee flexion and quadriceps demand can substantially increase patellofemoral loading.

In an athlete with PFPS, symptoms may develop when the demands being placed on the patellofemoral system exceed the athlete’s current ability to tolerate those demands.

Potential contributors include:

• Excessive or rapidly increased loading
• Dynamic knee valgus
• Hip or quadriceps dysfunction
• Trunk-control deficits
• Altered patellar mechanics
• Foot mechanics
• Mobility restrictions¹⁻⁴

However, no single mechanism explains every case.

PFPS should therefore not automatically be reduced to “patellar maltracking,” VMO weakness, or one biomechanical abnormality.

Typical Symptoms

Athletes commonly report:

• Peripatellar or retropatellar pain
• Pain with squatting
• Pain with stairs
• Running-related pain
• Pain with jumping or landing
• Pain after prolonged sitting
• Symptoms that increase with training volume¹⁻³

The clinical pattern is primarily one of pain during loaded knee flexion.

Functional Diagnosis

PFPS is primarily a clinical diagnosis.¹,⁴

Imaging is not required to confirm a typical presentation.

Functional diagnosis should integrate:

history + pain location + load provocation + functional testing + differential diagnosis.

One of the most important findings is reproduction of familiar peri- or retropatellar pain during a task that loads the knee in flexion.

Step 1: Identify the Symptom Pattern

The history should determine:

• Location of pain
• Duration and onset
• Recent changes in training volume
• Changes in running or jumping exposure
• Which movements provoke symptoms
• Pain during stair ascent or descent
• Pain with prolonged sitting
• Response during and after training

The clinician should look for a coherent load-related anterior knee pain pattern rather than relying on one named special test.

Step 2: Reproduce Symptoms With Loaded Knee Flexion

Next, the clinician should determine whether the athlete’s familiar anterior knee pain is reproduced during tasks that load the patellofemoral joint in knee flexion.

Common examples include:

• Squatting
• Single-leg squatting
• Step-down tasks
• Stair descent
• Running
• Jumping
• Landing
• Cutting

The key finding is not simply that the knee hurts.

The important question is whether familiar peri- or retropatellar pain is reproduced during loaded knee-flexion tasks.

In athletes, lower-demand tasks may not reproduce symptoms even when higher-load or higher-speed activities do. Therefore, testing should eventually reflect the athlete’s sport demands.

Step 3: Consider Differential Diagnosis

PFPS is a clinical diagnosis, but not all anterior knee pain is PFPS.

Depending on the athlete’s age, symptom location, trauma history, swelling, instability, locking, and irritability, clinicians should consider other possible conditions such as:

• Patellar tendinopathy
• Osgood-Schlatter disease
• Sinding-Larsen-Johansson syndrome
• Meniscal pathology
• Patellar instability
• Fat pad irritation
• Plica syndrome
• Osteochondral lesion
• Ligament injury
• Referred pain from the hip or lumbar spine

Clinicians should be especially cautious when symptoms include:

• Clear traumatic onset
• Significant swelling
• Locking
• Giving way
• Night pain
• Progressive symptoms
• Symptoms that do not match a typical PFPS pattern

Functional diagnosis should confirm that the clinical pattern is consistent with PFPS while also identifying findings that may suggest another condition.

Evaluate the Kinetic Chain

For an athlete, functional diagnosis should also investigate why sport demands may be exceeding the current capacity of the patellofemoral system.

Potential areas to assess include:

Hip and Trunk

• Hip abductor strength
• Hip extensor strength
• Hip external-rotator strength
• Trunk control

Knee

• Quadriceps capacity
• Eccentric control
• Knee-flexion strategy
• Dynamic valgus

Ankle and Foot

• Ankle dorsiflexion
• Foot posture
• Navicular drop
• Relevant pronation mechanics¹⁻⁴

Importantly, finding dynamic valgus does not prove that valgus is causing the pain.

The impairment should be linked to the athlete’s symptoms and meaningful sport function before it becomes a rehabilitation target.

Role of Imaging

Typical PFPS is primarily a clinical diagnosis, and imaging is not routinely required.¹,³,⁴

Imaging becomes more relevant when there is concern for:

• Osteochondral pathology
• Significant structural injury
• Patellar instability
• Trauma
• Atypical or persistent symptoms

Imaging should generally be used to investigate alternative or concomitant pathology rather than to “confirm” uncomplicated PFPS. Expert clinicians have similarly emphasized that diagnosis is clinical and imaging should mainly screen for other pathology.⁴

Treatment and Rehabilitation Overview

**Conservative rehabilitation is first-line management.**¹,³,⁴

The central framework is:

education + activity/load modification + progressive exercise therapy.

Phase 1: Pain and Load Management

Identify the activities currently exceeding the athlete’s patellofemoral capacity.

Examples may include:

• Increased running mileage
• Hills
• High jump volume
• Deep squatting
• Repetitive stairs
• Cutting volume

The goal is usually not complete rest.

Training should be temporarily modified to reduce excessive symptom provocation while maintaining tolerable activity.

Phase 2: Strength and Capacity

Current evidence generally supports rehabilitation addressing the hip and knee, often with trunk/core considerations, rather than relying on isolated quadriceps strengthening alone.¹,³,⁴

Treatment should still be individualized according to examination findings.

A 2025 randomized clinical trial found that functional strength training produced greater improvements in pain and knee function than standard strength training and was accompanied by increased gluteus maximus activation and reduced knee valgus.⁸

Phase 3: Mobility and Distal Contributors

When clinically relevant, rehabilitation may also address:

• Hip mobility
• Ankle dorsiflexion
• Foot function
• Relevant soft-tissue restrictions

A 2026 randomized trial in male collegiate athletes found that adding hip- and ankle-mobility-based rehabilitation improved pain, Kujala scores, hip rotation, ankle dorsiflexion, and dynamic balance.⁹

For selected patients with relevant foot findings, adding short-foot exercise to hip- and knee-focused rehabilitation has also improved pain, function, and balance compared with hip and knee exercise alone.¹²

Phase 4: Motor Control and Functional Retraining

Strength alone may not automatically change sport movement.

The athlete must learn to express newly developed capacity during:

• Squatting
• Step-down
• Landing
• Deceleration
• Cutting
• Running

In active females with PFPS, valgus-control instruction improved pain, dynamic valgus, hip torque, and functional performance.¹⁰

A 2026 randomized trial in recreational sprinters also found greater improvements in pain, dynamic balance, and hop performance with dynamic proprioceptive training compared with conventional strengthening.¹¹

Phase 5: Return to Sport

Return to sport should be criteria based rather than time based.

Relevant considerations may include:

• Pain-free or acceptable squatting
• Stair tolerance
• Running tolerance
• Quadriceps capacity
• Hip and trunk capacity
• Step-down control
• Jump/hop performance
• Balance
• Repeated-load tolerance
• Athlete confidence³,¹³

The final question is not simply whether everyday pain has disappeared.

It is whether the athlete can repeatedly tolerate the specific intensity, volume, speed, and movement demands of sport.