Patellofemoral Pain Syndrome (PFPS) Rehabilitation Protocol for Runners

Pathophysiology

Patellofemoral Pain Syndrome (PFPS), also known as runner's knee, is a common condition characterized by pain around the patella (kneecap). The exact etiology is often multifactorial, involving a combination of biomechanical, muscular, and training-related factors. Commonly, PFPS arises from abnormal patellar tracking within the trochlear groove of the femur. This maltracking can lead to increased stress and irritation of the articular cartilage on the posterior surface of the patella and/or the anterior surface of the femoral condyles.

Key contributing factors include:

• Muscle Imbalances: Weakness of the hip abductors (gluteus medius), hip external rotators, and quadriceps (specifically the vastus medialis oblique - VMO) can contribute to poor lower extremity alignment and patellar maltracking. Overactivity or tightness of the iliotibial band (ITB) and lateral retinaculum can also contribute.
• Biomechanical Abnormalities: Excessive pronation, genu valgum (knock-knees), femoral anteversion, and tibial torsion can alter lower extremity mechanics and increase stress on the patellofemoral joint.
• Training Errors: Rapid increases in training volume or intensity, inadequate warm-up, improper footwear, and running on hard or uneven surfaces can overload the patellofemoral joint.
• Patellar Instability: Previous patellar subluxation or dislocation can damage the supporting structures and predispose to PFPS.

Common Special Tests

Several special tests can aid in the diagnosis of PFPS. These tests assess pain provocation, patellar mobility, and muscle function. It's important to note that special tests alone are not definitive and should be interpreted in conjunction with a thorough history and physical examination.

• Patellar Grind Test (Clarke's Test): The patient lies supine with the knee extended. The examiner applies a downward pressure over the patella while asking the patient to contract their quadriceps. A positive test is indicated by pain or grinding sensation under the patella.
• Patellar Apprehension Test: The patient lies supine with the knee slightly flexed. The examiner gently pushes the patella laterally. A positive test is indicated by apprehension or guarding by the patient.
• Single Leg Squat Test: The patient stands on one leg and squats down. Observe for knee valgus (knee collapsing inward), pelvic drop, and trunk rotation. These findings suggest weakness of the hip abductors and/or core muscles.
• Ober's Test: Assess ITB tightness. The patient lies on their side, the hip is abducted and extended with the knee flexed. The examiner then allows the leg to adduct towards the table. A positive test is indicated if the leg remains abducted, indicating ITB tightness.
• Q-Angle Measurement: Measure the angle between a line drawn from the ASIS to the mid-patella and a line drawn from the tibial tubercle to the mid-patella. An increased Q-angle may suggest abnormal patellar tracking.

Rehabilitation Protocol

This protocol is a guideline and should be adjusted based on individual patient presentation, pain levels, and functional goals. Progression through phases is based on meeting specific criteria, not solely on time.

Phase I: Protection (Pain and Inflammation Management)

Goals: Reduce pain, swelling, and inflammation. Restore pain-free range of motion. Initiate gentle muscle activation.

• Activity Modification: Advise the patient to avoid activities that aggravate their pain, such as running, squatting, and prolonged sitting. Consider cross-training activities like swimming or cycling (with a high seat and low resistance).
• Pain Management: Apply ice packs for 15-20 minutes, 2-3 times per day. Consider using NSAIDs as prescribed by a physician.
• Range of Motion (ROM):
  • Gentle Patellar Mobilization: Perform superior, inferior, medial, and lateral glides to improve patellar mobility.
  • Heel Slides: Perform gentle knee flexion and extension within a pain-free range.
  • Hamstring Stretches: Gentle stretching to address potential tightness, such as towel hamstring stretch.
• Muscle Activation:
  • Quad Sets: Isometric quadriceps contractions with the knee fully extended. Focus on VMO activation.
  • Straight Leg Raises (SLRs): Perform SLRs in all directions (forward, sideways, backward) with emphasis on maintaining proper form and avoiding hip hiking.
  • Gluteal Sets: Isometric gluteal contractions to improve hip stability.
• Criteria for Progression to Phase II:
  • Minimal pain at rest.
  • Pain-free ROM within functional limits (approximately 0-90 degrees of knee flexion).
  • Ability to perform quad sets and SLRs without pain.

Phase II: Loading (Strength and Endurance)

Goals: Improve quadriceps strength, hip strength, and core stability. Gradually increase tolerance to weight-bearing activities.

• Strength Training:
  • Mini Squats: Progress from wall sits to mini squats (0-45 degrees of knee flexion) with proper form (avoiding knee valgus).
  • Leg Press: Start with low weight and gradually increase as tolerated, focusing on controlled movements. Limit range of motion to avoid pain.
  • Step-Ups: Begin with low step heights and gradually increase as tolerated. Focus on maintaining proper form and avoiding knee valgus.
  • Hip Abduction and External Rotation Exercises: Use resistance bands to perform sidelying hip abduction, clamshells, and monster walks.
  • Hamstring Curls: Progress from prone hamstring curls to standing hamstring curls with resistance bands or weights.
  • Core Stabilization Exercises: Planks, side planks, bird dogs to improve core stability.
• Endurance Training:
  • Stationary Biking: Begin with low resistance and gradually increase duration and resistance. Ensure proper seat height to minimize patellofemoral stress.
  • Elliptical: Start with short intervals and gradually increase duration and intensity.
  • Walking Progression: Progress from short walks on flat surfaces to longer walks on varied terrain.
• Proprioceptive Training:
  • Single Leg Stance: Practice maintaining balance on one leg, gradually increasing duration and adding perturbations (e.g., reaching, head turns).
  • Balance Board/Wobble Board Exercises: Perform balance exercises on a balance board or wobble board to improve proprioception and dynamic stability.
• Criteria for Progression to Phase III:
  • Pain-free during functional activities such as walking, stairs, and squats.
  • Good quadriceps and hip strength (at least 80% of contralateral limb).
  • Adequate balance and proprioception.

Phase III: Return to Function (Running Progression)

Goals: Gradually return to running at pre-injury level. Optimize running mechanics. Prevent recurrence of symptoms.

• Running Progression: Follow a gradual return-to-running program, such as the Couch-to-5K program, or a customized program based on individual needs.
  • Walk/Run Intervals: Begin with short intervals of running alternating with walking (e.g., 1 minute run, 1 minute walk). Gradually increase the running intervals and decrease the walking intervals.
  • Distance Progression: Gradually increase the total distance run each week, but no more than 10% increase per week.
  • Surface Progression: Start running on flat, even surfaces (e.g., track, treadmill) and gradually progress to running on varied terrain (e.g., trails, hills).
• Running Mechanics Assessment and Correction: Evaluate running form and address any biomechanical abnormalities.
  • Cadence: Increase cadence (steps per minute) to reduce impact loading on the patellofemoral joint.
  • Stride Length: Shorten stride length to reduce overstriding.
  • Foot Strike: Encourage midfoot strike to reduce impact loading.
  • Pelvic Stability: Maintain pelvic stability during running to prevent excessive hip adduction and internal rotation.
• Plyometric Training:
  • Jump Rope: Start with low-impact jump rope exercises and gradually progress to higher-impact exercises.
  • Box Jumps: Perform box jumps with proper landing mechanics to improve power and explosiveness.
  • Hopping Exercises: Progress from double-leg hopping to single-leg hopping to improve leg strength and balance.
• Maintenance Program: Continue performing strength training and flexibility exercises to maintain strength, endurance, and flexibility.
• Criteria for Full Return to Running:
  • Pain-free running at pre-injury distance and intensity.
  • Good quadriceps and hip strength.
  • Optimal running mechanics.
  • Ability to perform all functional activities without pain.

Important Considerations:

• This protocol provides a general guideline and needs to be individualized based on the patient's specific needs and response to treatment.
• Communication between the physical therapist, patient, and referring physician is crucial for optimal outcomes.
• Patient education is essential to ensure adherence to the rehabilitation program and to prevent recurrence of symptoms. Educate the patient regarding proper warm-up, cool-down, footwear, and training techniques.