Personalized Blood Flow Restriction for Anterior Cruciate Ligament Rehabilitation

Study Overview
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Brief Summary
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This is a cross-sectional study on the use of personalized blood flow restriction during rehabilitation exercises and its effects on biomechanics on people who have had an anterior cruciate ligament reconstruction and healthy controls

Detailed Description
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Rehabilitation after surgical reconstruction of the anterior cruciate ligament (ACL) aims to reestablish the function of the knee. However, regaining previous levels of strength is challenging, with long-term muscle weakness frequently reported and thought to play a key role in the increased risk of knee osteoarthritis for individuals with a history of ACL damage. Effectively building muscle strength requires exercises with high resistance loads, however the joint stress and risk of further injury makes these types of activities inappropriate and unsafe for those rehabilitating after ACL reconstruction surgery and other injuries. Personalized blood flow restriction (BFR) training is a technique where the blood flow to the muscles being exercised is controlled by a pressure cuff to a predefined level, and has been shown to increase strength while exercising with significantly lower loads. Early results have been promising, however the effects of BFR on the biomechanics of the exercise as well as the acceptability in the ACL reconstruction population have not been explored. In this application, we propose a cross-sectional study designed to test the acceptability of BFR training for those undergoing rehabilitation from ACL reconstruction surgery and healthy controls during free standing exercises. We will also investigate the biomechanical effects of this rehabilitation technique. This application is part of a larger program of musculoskeletal research in this area being developed by the team. The results from the proposed project will inform the design of a clinical trial of personalized BFR after ACL reconstruction.

Official Title
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Personalized Blood Flow Restriction for Anterior Cruciate Ligament Rehabilitation

Conditions
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Anterior Cruciate Ligament Tear

Intervention / Treatment
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* Device: Blood flow restriction


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria (ACL-R group): Must be undergoing rehabilitation for anterior cruciate ligament reconstruction surgery Must be at least 3 months post surgery. Attending clinician should confirm that they are able to take part in the trial Exclusion Criteria: Any other orthopaedic, neurological, or other condition within the last 12 months that would affect ability to carry out the required exercises Any medical conditions that may affect circulation including, but not limited to, deep vein thrombosis, high blood pressure, and cardiac disease

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Anterior cruciate ligament reconstruction group<br>Single session blood flow restriction of lower limb to individuals who have undergone anterior ligament reconstruction surgery | Device: Blood flow restriction<br>* Intervention restricts blood flow to the lower limb as a percentage of the limb occlusion pressure<br>|
| Active Comparator: Control group<br>Single session blood flow restriction of lower limb to individuals who have no musculoskeletal injuries | Device: Blood flow restriction<br>* Intervention restricts blood flow to the lower limb as a percentage of the limb occlusion pressure<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee Flexion | Maximum difference in flexion motion of knee while performing exercise between baseline and blood flow restriction condition. Measured in degrees | 6 minutes | 
| Knee Internal Rotation | Maximum difference in internal rotation of knee while performing exercise between baseline and blood flow restriction condition. Measured in degrees | 6 minutes | 
| Knee Varus | Maximum difference in varus motion of knee while performing exercise between baseline and blood flow restriction condition. Measured in degrees | 6 minutes | 
| Hip Flexion | Maximum difference in flexion motion of hip while performing exercise between baseline and blood flow restriction condition. Measured in degrees | 6 minutes | 
| Hip Adduction | Maximum difference in adduction motion of hip while performing exercise between baseline and blood flow restriction condition. Measured in degrees | 6 minutes | 
| Hip Internal Rotation | Maximum difference in internal rotation motion of hip while performing exercise between baseline and blood flow restriction condition. Measured in degrees | 6 minutes | 
| Knee Extension Moment | Maximum difference in extension moment of knee while performing exercise between baseline and blood flow restriction condition. Measured in Newton meters per kilogram | 6 minutes | 
| Knee Internal Rotation Moment | Maximum difference in internal rotation moment of knee while performing exercise between baseline and blood flow restriction condition. Measured in Newton meters per kilogram | 6 minutes | 
| Knee Adduction Moment | Maximum difference in adduction moment of knee while performing exercise between baseline and blood flow restriction condition. Measured in Newton meters per kilogram | 6 minutes | 
| Hip Extension Moment | Maximum difference in extension moment of hip while performing exercise between baseline and blood flow restriction condition. Measured in Newton meters per kilogram. | 6 minutes | 
| Hip Adduction Moment | Maximum difference in adduction moment of hip while performing exercise between baseline and blood flow restriction condition. Measured in Newton meters per kilogram | 6 minutes | 
| Hip Internal Rotation Moment | Maximum difference in internal rotation moment of hip while performing exercise between baseline and blood flow restriction condition. Measured in Newton meters per kilogram | 6 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise Difficulty Score | Numerical Analogue Scale, 0-10, higher scores indicate greater difficulty | 6 minutes | 
| Exercise Discomfort Score | Numerical Analogue Scale, 0-10, higher scores indicate greater discomfort | 6 minutes |