A Controlled Trial on Recreational Runners With Patellofemoral Pain

Study Overview
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Brief Summary
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From a rehabilitation point of view, while several approaches exist to retrain runners with PFPS, it is not clear which one is most effective, or why. The goals of this randomised-controlled trial are: 1) to compare the effectiveness of three rehabilitation programs on pain and functional limitations of runners with PFPS and 2) to explain why the programs are effective or not based on laboratory analyses. After baseline evaluation, runners will be randomly assigned to one of three treatment groups, each with a specific 8-week rehabilitation program aimed at addressing the efficiency of a specific type of retraining. These groups are: 1) Control; 2) muscle recruitment; 3) reducing knee loading during running. The investigators hypothesis is that the intervention targeting a reduction in knee loading will be significantly more effective in reducing symptoms and improving function of runners with patellofemoral pain syndrome.

Detailed Description
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Hypothesis will be tested using symptoms and functional status questionnaires. In addition, mechanistic analyses will be conducted using a running assessment using an instrumented treadmill and kinematics analyses.

Official Title
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A Randomised Controlled Trial on Recreational Runners With Patellofemoral Pain: Effects of Rehabilitation Approaches Based on Specific Underlying Mechanisms

Conditions
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Patellofemoral Pain (PFPS)

Intervention / Treatment
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* Other: Education
* Other: Exercise program
* Other: Gait retraining


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Running mileage at least 15km Symptoms since at least 3 months Pain level at least 3/10 during running and 3 activities among: kneeling, squatting, stairs and resisted knee extension Score lower than 85/100 on the KOS-ADLS Exclusion Criteria: History of knee surgery or patellar dislocation Pain believed to originate either from meniscus or from patellar tendon Pain following an acute trauma Concurrent lower limb injuries History of neurological, inflammatory, rheumatoid disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Control<br>Education will be given on how to modify running training to encourage improvement of symptoms. | Other: Education<br>* Education on running training modifications depending on symptoms (decrease running speed, spread running volume throughout the week, run/walk intervals, avoid downhill and stairs running). Education about symptoms will also be provided.<br>|
| Experimental: Muscle recruitment<br>Subjects will receive an additional exercise program targeting non task-specific strengthening and motor control exercises of the lower limb. | Other: Education<br>* Education on running training modifications depending on symptoms (decrease running speed, spread running volume throughout the week, run/walk intervals, avoid downhill and stairs running). Education about symptoms will also be provided.<br>Other: Exercise program<br>* A home-based program including strengthening and motor control exercises will be prescribed. The program will include 4 different phases of 2 weeks.<br>|
| Experimental: Reduction of knee loading<br>Subjects will receive additional personalized advice on how to modify running gait in order to reduce mechanical loads at the knee (gait retraining). | Other: Education<br>* Education on running training modifications depending on symptoms (decrease running speed, spread running volume throughout the week, run/walk intervals, avoid downhill and stairs running). Education about symptoms will also be provided.<br>Other: Gait retraining<br>* Running gait will be modified to reduce knee loading while running (step frequency, impact, foot strike pattern).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in symptoms and function using a self-reported questionnaire, the Activities of Daily Living Scale of the Knee Outcome Survey (KOS-ADLS) | A validated self-reported questionnaire (found to have the best psychometric properties in this population by a systematic review; Esculier et al., Disabil Rehabil 2013;35(26):2181-90) will be used to assess the severity of symptoms and functional limitations during the activities of daily living because of knee impairment. Changes in scores to this questionnaire will allow to compare the efficacy of rehabilitation protocols. | After 4 weeks and 8 weeks of rehabilitation; 3 months after the end of the rehabilitation program | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in pain scores using Visual analog scales (VAS) | Visual analog scales will be used to assess levels of usual pain, worst pain and pain during running. Changes in scores to these scales will allow to compare the efficacy of rehabilitation protocols. These pain scales have been validated in this population. | After 4 weeks and 8 weeks of rehabilitation; 3 months after the end of the rehabilitation program | 
| Global rating of change (GRC) | Self-reported outcome used to monitor perception of improvement or worsening of the condition following the intervention. | After the intervention (8 weeks) | 
| Changes in the vertical loading rate of ground reaction forces during treadmill running | Vertical ground reaction forces and vertical loading rate during running on a Bertec instrumented treadmill. The average and instantaneous rise in vertical ground reaction forces will be considered between initial contact and initial peak in vertical forces. Data will be collected during running between 8-10km/h on a Bertec instrumented treadmill. | Baseline and after the intervention (8 weeks) | 
| Changes in ankle, knee, hip and pelvis kinematics during the stance phase of running | Analysis of 3-dimensions motion of the lower limbs during running using VICON cameras. Peak angles and angular excursions will be assessed. | Baseline and after the intervention (8 weeks) | 
| Changes in patellofemoral joint load during the stance phase of running | Using inverse dynamics, patellofemoral joint load during the stance phase of running will be estimated by combining kinematics data with force plates data. | Baseline and after the intervention (8 weeks) | 
| Changes in lower limb muscle strength | Maximum isometric strength testing of the knee extensors and hip abductors, extensors and external rotators will be assessed using a handheld dynamometer with standard procedures. | Baseline and after the intervention (8 weeks) |