Patellofemoral Pain Syndrome
Lower LimbOverview
Patellofemoral pain syndrome (PFPS) is a common anterior knee condition characterized by pain around or behind the patella, often aggravated by activities involving knee flexion such as climbing stairs, squatting, or prolonged sitting. It is typically a non-inflammatory condition resulting from altered patellar tracking and increased patellofemoral joint stress. PFPS accounts for 25-40% of all knee pain presentations in clinical practice.
Pathophysiology
PFPS results from abnormal patellar tracking within the femoral groove, causing increased pressure on articular cartilage and surrounding structures. Primary causative factors include: (1) quadriceps weakness or imbalance, particularly vastus medialis obliquus (VMO) insufficiency; (2) hip muscle weakness (gluteus medius, maximus) leading to excessive hip adduction and internal rotation; (3) tight lateral structures (vastus lateralis, iliotibial band, lateral retinaculum); (4) foot biomechanics (excessive pronation, pes planus); (5) femoral anteversion or increased Q-angle; (6) postural dysfunction and altered movement patterns. Repetitive microtrauma to patellofemoral articular surfaces and periarticular tissues causes localized inflammation, pain sensitization, and proprioceptive deficits.
Typical Presentation
Site
Retropatellar or peripatellar region, particularly around medial facet or central patella; may be diffuse across anterior knee
Quality
Dull ache, pressure sensation, or sharp localized pain; often described as 'deep' or 'inside' the knee
Intensity
Mild to moderate (3-6/10), variable throughout day, often worse by end of day; rarely severe resting pain
Aggravating
Stairs (especially descending), squatting, prolonged sitting with knees bent (cinema sign), lunges, jumping, running on hard surfaces, kneeling, activities increasing knee flexion load
Relieving
Rest, leg elevation, ice application, knee extension, activity modification, sitting with leg extended
Associated
Anterior knee swelling (mild), sense of instability or 'giving way', quadriceps weakness, hip weakness, stiffness after inactivity, clicking or crepitus with movement, tight hip flexors and lateral knee structures
Orthopaedic Tests
Quadriceps Angle (Q-angle)
Procedure
Patient supine, legs straight, quadriceps relaxed. Draw a line from the ASIS to the centre of the kneecap and a second line from the centre of the kneecap to the tibial tuberosity; measure the angle between them. Compare sides.
Positive Finding
A larger angle on one side, or a larger angle than expected.
Interpretation
Describes alignment, not diagnosis. The Q-angle varies with how it is measured and is similar in people with and without patellofemoral pain. Diagnosis rests on the history: pain around or behind the kneecap on squatting, stairs, running or sitting. The previously cited source was fabricated; the Q-angle has poor diagnostic value and is frequently present in asymptomatic individuals.
Single-Leg Squat Test
Procedure
Ask the patient to stand on one leg and squat slowly to about 45–60° of knee flexion and back up, five times, while you watch from the front.
Positive Finding
Reproduction of pain around or behind the kneecap, or the knee moving inwards, the pelvis dropping or the trunk leaning.
Interpretation
Reproduction of the familiar pain supports patellofemoral pain. Movement quality guides hip and knee rehabilitation. Poor control is also common in people without pain. A useful test of neuromuscular control, but no validated sensitivity/specificity for diagnosing patellofemoral pain syndrome.
Step-Down Test
Procedure
Patient stands on a step on the affected leg and slowly lowers the other heel to touch the floor, five times, while you watch from the front.
Positive Finding
Reproduction of pain around the kneecap, or the knee moving inwards and the pelvis dropping.
Interpretation
Reproduction of pain supports patellofemoral pain and gives a measure to track. Movement quality guides rehabilitation. No validated diagnostic-accuracy data for patellofemoral pain syndrome.
Lateral Step-Up Test
Procedure
Patient stands side-on to a step, steps up with the affected leg, then lowers back down slowly.
Positive Finding
Reproduction of pain around the kneecap, or poor control of the knee or pelvis.
Interpretation
A functional loading test for monitoring and exercise planning, not a diagnostic test. No validated diagnostic-accuracy data for patellofemoral pain syndrome.
Y-Balance Test (Lower Quarter)
Procedure
Patient stands on one leg on the centre of the test kit and reaches as far as possible with the other foot in three directions (anterior, posteromedial, posterolateral). Record the best reach in each direction and compare legs.
Positive Finding
Shorter reach on one side, or loss of balance.
Interpretation
A measure of dynamic balance and control, used for rehabilitation and return-to-sport decisions. It is not a diagnostic test for patellofemoral pain. The Y-Balance test predicts injury risk and measures dynamic balance; it is not a diagnostic test for patellofemoral pain syndrome.
Patellar Tilt Test
Procedure
Patient supine, knee straight and relaxed. Try to lift the lateral border of the kneecap upwards, and compare with the other side.
Positive Finding
The lateral border cannot be lifted to horizontal, or less than on the other side.
Interpretation
Suggests a tight lateral retinaculum, a possible contributor to patellofemoral pain that can guide taping and soft-tissue treatment. Hip abductor strength, which this entry previously mixed in, should be tested separately.
⚠ Red Flags
- •Acute severe trauma with significant swelling and inability to bear weight (rule out fracture, ligamentous injury)
- •Knee locked in flexion or extension (meniscal pathology)
- •Severe effusion with systemic symptoms (septic arthritis, inflammatory arthropathy)
- •Unilateral calf swelling with calf pain and warmth (DVT)
- •Signs of acute ACL or MCL rupture (acute instability, hemarthrosis)
- •Swelling, warmth, and erythema suggesting infection or acute inflammatory process
⚡ Yellow Flags
- •High pain catastrophizing or fear-avoidance beliefs related to knee pain
- •Significant psychological distress or depression affecting rehabilitation engagement
- •Excessive reliance on passive treatments without active participation
- •Inconsistent reporting of pain severity versus functional limitation
- •Social or occupational stressors limiting rehabilitation compliance
- •Secondary gain factors or litigation involvement
- •Poor sleep quality exacerbating pain perception
Osteopathic Techniques
Region
Hip musculature (gluteus medius, gluteus maximus, hip rotators)
Technique
Rationale
Myofascial release and friction techniques to address hip abductor and external rotator tightness, improving hip stability and reducing compensatory femoral adduction and internal rotation that drives abnormal patellar tracking
Region
Vastus lateralis and iliotibial band
Technique
Rationale
Targeted soft tissue manipulation to reduce lateral knee tension and myofascial restrictions that contribute to lateral patellar tracking and increased patellofemoral compression forces
Region
Quadriceps musculature (all quadriceps components)
Technique
Rationale
Muscle energy techniques to normalize quadriceps tone, address VMO inhibition, and improve neuromuscular control of patellar positioning during functional movements
Region
Patellofemoral joint and surrounding structures
Technique
Rationale
Gentle patellofemoral joint mobilization to improve synovial fluid distribution, reduce cartilage stress concentration, and normalize joint mechanics without excessive compression
Region
Hip joint and lumbar spine
Technique
Rationale
Mobilization of hip capsule and lumbar segments to address postural dysfunction, correct lower limb mechanical alignment, and improve kinetic chain function from proximal to distal
Region
Foot and ankle (talus, subtalar joint, plantar fascia)
Technique
Rationale
Treatment of foot pronation and ankle stiffness through myofascial release and joint mobilization, correcting biomechanical foot posture that contributes to altered knee mechanics and patellar tracking
Rehabilitation Exercises
Quadriceps and Hip Flexor Stretching
Iliotibial Band and Lateral Knee Stretching (Modified Ober Position)
Gastrocnemius and Soleus Calf Stretching
Vastus Medialis Obliquus Strengthening (Terminal Knee Extension with Band)
Gluteus Medius Strengthening (Side-Lying Hip Abduction)
Gluteus Maximus Strengthening (Bridging with Single-Leg Progression)
Hip External Rotation Strengthening (Clamshells)
Wall Squats with Attention to Knee Alignment
Step-Up and Step-Down with Proper Femoral Alignment
Single-Leg Stance with Hip Stability Focus
Lateral Stepping with Resistance Band
Low-Impact Aerobic Activity (Swimming, Cycling with Proper Bike Fit, Elliptical)
Referral Criteria
- •Persistent pain unresponsive to conservative treatment over 6-8 weeks of structured rehabilitation
- •Suspected structural damage (meniscal pathology, cartilage defect) indicated by locking, catching, or positive McMurray test
- •Signs of patellofemoral osteoarthritis with imaging confirmation and progressive functional decline
- •Suspected patellar instability or dislocation history requiring orthopedic surgical evaluation
- •Concurrent knee ligamentous injury (ACL, MCL, PCL) with positive special tests and imaging confirmation
- •Severe knee swelling, effusion, warmth, or systemic symptoms suggesting inflammatory or septic arthritis
- •Significant functional limitation preventing ADLs or work duties unresponsive to conservative care
- •Complex cases with multiple comorbidities or psychosocial factors limiting conservative management success