The Effects of Preoperative Blood Flow Restriction Training in Patients Undergoing ACL Reconstruction (BFRACL)

March 25, 2024 updated by: Women's College Hospital

The Effects of Preoperative Blood Flow Restriction Training in Patients Undergoing ACL Reconstruction: A Pilot Randomized Control Trial

This prospective feasibility study is designed to assess pre-operative BFR in patients awaiting ACL reconstruction. This study will serve the following: (1) to determine if BFR improves strength testing prior to surgery and (2) to determine if BFR reduces QF muscle group atrophy prior to surgery. Additionally, preliminary results on pre-operative clinical and quality of life scores will be collected. If this study shows encouraging results, it will serve as a template for a more comprehensive randomized control trial.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Quadriceps femoris (QF) muscle function is an integral factor in the rehabilitation and overall outcome after lower extremity injury or surgical intervention. Atrophy of this muscle group is a common finding in patients undergoing anterior cruciate ligament (ACL) reconstruction. This is due to the immobility prior to surgery, vascular ischemia caused by a tourniquet intra-operatively and inability to perform high load strength training in the early post-operative period. A deficit in QF muscle strength can result in excessive joint loading and be a contributing factor in the early onset of osteoarthritis of the knee. It should be noted that a loss of strength in this primary knee extensor mechanism muscle group can persist for up to 2 years after surgery. Thus, the reduction of QF atrophy and maintenance of strength during an intervention such as an ACL reconstruction has large implications for the overall post-operative outcome and natural history of the knee joint.

In order to combat the challenges of muscle atrophy for patients with an ACL injury, blood flow restriction (BFR) training has been shown to have beneficial effects in the post-operative period specifically. The process of using BFR therapy involves the application of an extremity tourniquet to occlude venous outflow and restrict arterial inflow. Thus, an anaerobic environment is created to promote muscle hypertrophy by having cells upregulate cell signalling, protein synthesis and ultimately myogenic proliferation. The use of BFR during lower extremity rehabilitation has shown that its simultaneous use with low load resistance training can have similar hypertrophic effects to isolated high load resistance training. This is ideal for patients who are initially unable to perform high intensity exercises shortly after an ACL reconstruction surgery, but are attempting to reduce overall QF atrophy.

However, the use of BFR in the pre-operative period has yet to be well established. Preconditioning with an ischemic environment may provide an effective way to reduce QF atrophy with low load exercises while awaiting surgery. Additionally, having a period of sensitization with anaerobic conditions prior to surgery, may provide some resistance to the damaging effects of a tourniquet intra-operatively. The limited studies that have attempted to use BFR therapy prior to ACL surgery have had short intervention periods, small sample sizes and outcome variables that have not assessed overall clinical outcome. If BFR in the pre-operative setting can be shown to provide beneficial effects, it will be a valuable tool in maximizing the overall outcome of patients undergoing ACL reconstruction.

This prospective feasibility study has been designed to assess pre-operative BFR in patients awaiting ACL reconstruction. This study will serve the following: (1) to determine if BFR improves strength testing prior to surgery and (2) to determine if BFR reduces QF muscle group atrophy prior to surgery. Additionally, preliminary results on pre-operative clinical and quality of life scores will be collected. If this study shows encouraging results, it will serve as a template for a more comprehensive randomized control trial.

Study Type

Interventional

Enrollment (Actual)

32

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5G 1X5
        • Mount Sinai Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Sagittal Knee instability caused by ACL tear requiring surgical reconstruction
  • Minimum 4 weeks since the time of injury

  • Age 18 to 50 years

    • Range of motion required

      ▪ Active extension deficit <5o, Active flexion > 120o

    • No previous surgery to affected knee

Exclusion Criteria:

  • Functional impairment (neuro disease, gait abnormality, ambulatory aids at baseline)
  • Severe spine or lower limb injuries
  • Comorbidities including cardiovascular, respiratory or metabolic disease, blood coagulation disorders, current smoker

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Physiotherapy with Blood Flow Restriction Group
This group underwent a physiotherapy protocol while using Blood Flow Restriction adjunctive therapy prior to ACL reconstruction.
Device: Blood Flow Restriction Therapy
Patients wear a personalized tourniquet pressure system on their involved thigh while they perform a series of leg press machine exercises. This tourniquet is inflated.
Other Names:
  • BFR
Sham Comparator: Physiotherapy without Blood Flow Restriction Group
This group underwent a physiotherapy protocol without using Blood Flow Restriction adjunctive therapy prior to ACL reconstruction.
Device: Blood Flow Restriction Therapy Sham
Patients wear a personalized tourniquet pressure system on their involved thigh while they perform a series of leg press machine exercises. This tourniquet is not inflated.
Other Names:
  • Sham BFR Comparison Group

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Biodex Strength Testing
Time Frame: Baseline testing 1 day prior to physiotherapy initiation and Post intervention testing performed 1 day after physiotherapy completion but before ACL surgery.
Quadriceps and Hamstring Muscle Strength and Endurance testing. Maximal peak torque (FT-LBS) was recorded for both knee flexion and extension at 60 degrees / second (indicative of strength) and 180 degrees / second (indicative of endurance).
Baseline testing 1 day prior to physiotherapy initiation and Post intervention testing performed 1 day after physiotherapy completion but before ACL surgery.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Short Form Health Survey 12 (SF-12)
Time Frame: Baseline testing 1 day prior to physiotherapy initiation and Post intervention testing performed 1 day after physiotherapy completion but before ACL surgery.
Patient Reported Outcome Measure. Scores range from 0 to 100, with higher scores indicating better physical and mental health functioning.
Baseline testing 1 day prior to physiotherapy initiation and Post intervention testing performed 1 day after physiotherapy completion but before ACL surgery.
Knee Injury and Osteoarthritis Outcome Score (KOOS)
Time Frame: Baseline testing 1 day prior to physiotherapy initiation and Post intervention testing performed 1 day after physiotherapy completion but before ACL surgery.
Patient Reported Outcome Measure. Scores are transformed to a 0-100 scale, with zero representing extreme knee problems and 100 representing no knee problems.
Baseline testing 1 day prior to physiotherapy initiation and Post intervention testing performed 1 day after physiotherapy completion but before ACL surgery.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Women's College Hospital

Investigators

  • Principal Investigator: John Theodoropoulos, MD, FRCSC, Dovigi Sports Medicine Clinic, Mount Sinai Hospital, Toronto, Canada

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 1, 2021

Primary Completion (Actual)

October 31, 2023

Study Completion (Actual)

January 31, 2024

Study Registration Dates

First Submitted

March 11, 2024

First Submitted That Met QC Criteria

March 25, 2024

First Posted (Actual)

April 2, 2024

Study Record Updates

Last Update Posted (Actual)

April 2, 2024

Last Update Submitted That Met QC Criteria

March 25, 2024

Last Verified

March 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 20-0070-E

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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