Anterior Cruciate Ligament Rupture
Conditions
Keywords
BFR, ACL, rehabilitation
Brief summary
The main objective is to determine the impact of Blood Flow Restriction (BFR) therapy, in comparison to a standard rehabilitation protocol, on preventing atrophy, improving quadriceps strength and improving functional outcomes of patients recovering from ACL reconstruction. The investigators hypothesize that patients undergoing BFR therapy after ACL reconstruction surgery will have better functional outcomes than those undergoing normal rehabilitation without BFR therapy.
Detailed description
Recovery from anterior cruciate ligament (ACL) reconstruction involves early physical therapy to promote muscular development. Traditional training regimens are based on the concept that muscle growth is induced with high resistance exercises of at least 65-70% of 1-repetition maximum. Achieving a high resistance level can be challenging in the early post-surgical patient who may be limited by pain, muscle atrophy, diminished proprioception, and psychological factors. Increasing evidence has suggested that Blood Flow Restriction (BFR) in resistance training, while transmitting a decreased load (25-50% of 1-repetition maximum) across the surgical site, may provide an additional benefit of inducing muscular development similar to that of high intensity exercises . Augmenting exercises with BFR involves an external pressure cuff applied to the proximal portion of the extremity, which is inflated to a pressure that restricts venous outflow while allowing arterial inflow to continue. This creates a physiologic environment for the patient to gain the hypertrophic effect of high resistance training, though at a lower and safer intensity. Studies suggest that BFR stimulates muscular development through an increase in metabolic stress, muscle fiber recruitment, cell swelling, and protein synthesis.
Interventions
DEVICEBlood Flow Restriction Therapy
A wide pressure cuff will be applied to the upper thigh prior to starting strengthening exercises. The cuff is inflated to 80% of resting systolic blood pressure. The cuff remains inflated for the entirety of the exercise (4 sets of a specific movement). Once the exercises are completed, it is deflated for a minimum of one minute before the next type of exercises are started.
OTHERACL Reconstruction rehabilitation
post-operative rehabilitation according to current standards of care
Sponsors
Inova Health Care Services
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
13 Years to 50 Years
Healthy volunteers
No
Inclusion criteria
1. Age 13-35 years at the time of surgery 2. Anterior Cruciate Ligament (ACL) reconstruction 3. Using a physical therapy center with Blood Flow Restriction capabilities.
Exclusion criteria
1. Concomitant ligament reconstruction 2. Concurrent procedures that require delayed weight bearing (ie: High Tibial Osteotomy (HTO), multi-ligament reconstruction, microfracture, etc) 3. History of Deep Vein Thrombosis (DVT)/Pulmonary Embolism (PE) 4. Immunocompromising conditions (ie: Rheumatoid arthritis, chronic steroid use, etc.) 5. History of coagulation disorders or current use of anticoagulants 6. Completion of physical therapy at a location not affiliated with the study 7. Pregnancy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Quadriceps Tendon Strength | Tracked from initiation of therapy 2 weeks post-op through 12 weeks post-op. | We will measure quadriceps tendon strength (closed chain) strength using a hand-held dynamometer placed just distal to the knee joint on the posterior calf with the patient in the supine position. The outcome will be reported biweekly as a percentage of the strength of the contralateral side, and then finally reported as a change in strength from the first measurement to the final measurement. The results reported in this data table refer to the percent strength of the operated leg when compared to the contralateral side. The change in strength results can be found in the statistical analysis section. |
| International Knee Documentation Committee (IKDC) Questionnaire Score | Measured preoperatively and at 12 weeks post-op. | The International Knee Documentation Committee (IKDC Questionnaire) is a knee-specific patient-reported outcome measure. The IKDC Questionnaire is a subjective scale that provides patients with an overall function score. The questionnaire looks at 3 categories: symptoms, sports activity, and knee function. Scores are obtained by summing the individual items, then transforming the crude total to a scaled number that ranges from 0 to 100. This final number is interpreted as a measure of function with higher scores representing higher levels of function. |
| Visual Analog Score | Measured preoperatively, at 2-weeks post-op, 6 weeks post-op, and 12 weeks post-op | The visual analog scale (VAS) is a validated, subjective measure for acute and chronic pain. Scores are recorded by making a handwritten mark on a 10-cm line that represents a continuum between no pain and worst pain, with no pain corresponding to a VAS score of 0 and worst pain corresponding to a VAS score of 10. |
| Degrees of Knee Extension | Tracked in the perioperative week and then from initiation of therapy 2 weeks post-op through 12 weeks post-op. | Degrees of knee extension will be measured on the operative side by a licensed physical therapist, with zero degrees indicating the knee completely at extension and negative degrees indicating degrees of hyperextension. The outcome will be reported biweekly and then finally reported as a change in degrees from the first measurement to the final measurement. The results reported in this data table refer to the degrees of knee extension at each reported time point. The change in knee extension results can be found in the statistical analysis section. |
| Thigh Circumference | Tracked in the perioperative week and then from initiation of therapy 2 weeks post-op through 12 weeks post-op. | A tape measure will be used to measure the thigh circumference 15 cm proximal to the superior pole of the patella. The outcome will be reported biweekly as a percentage of the contralateral side, and then finally reported as a change in circumference from the first measurement to the final measurement. The results reported in this data table refer to the percent circumference of the operated leg when compared to the contralateral side. The change in circumference results can be found in the statistical analysis section. |
| Degrees of Knee Flexion | Tracked in the perioperative week and then from initiation of therapy 2 weeks post-op through 12 weeks post-op. | Degrees of knee flexion will be measured on the operative side by a licensed physical therapist. The outcome will be reported biweekly and then finally reported as a change in degrees from the first measurement to the final measurement. The results reported in this data table refer to the degrees of knee flexion at each reported time point. The change in knee flexion results can be found in the statistical analysis section. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Adverse Effects | Tracked from initiation of therapy 2 weeks post-op through 12 weeks post-op | Observation of any adverse events associated with BFR therapy, such as numbness, cuff-site pain, and bruising. |
Countries
United States
Participant flow
Recruitment details
Patients were enrolled from two fellowship trained sports medicine orthopedic surgeons at a large health system from November 2018 to November 2021.
Pre-assignment details
Of 49 enrolled patients, 45 met inclusion/exclusion criteria and were randomized to treatment.
Participants by arm
| Arm | Count |
|---|---|
| BFR Therapy This group will undergo physical therapy exercises per the standard of care, with the addition of Blood Flow Restriction (BFR) utilizing a wide pressure cuff. BFR exercises will be initiated two weeks post-op, and continued for 16 weeks.
Blood Flow Restriction Therapy: A wide pressure cuff will be applied to the upper thigh prior to starting strengthening exercises. The cuff is inflated to 80% of resting systolic blood pressure. The cuff remains inflated for the entirety of the exercise (4 sets of a specific movement). Once the exercises are completed, it is deflated for a minimum of one minute before the next type of exercises are started.
ACL Reconstruction rehabilitation: post-operative rehabilitation according to current standards of care | 25 |
| No BFR This group of patients will undergo physical therapy exercises per the current standard of care after their ACL reconstruction without BFR
ACL Reconstruction rehabilitation: post-operative rehabilitation according to current standards of care | 20 |
| Total | 45 |
Baseline characteristics
| Characteristic | Total | BFR Therapy | No BFR |
|---|---|---|---|
| Age, Continuous | 26.8 years STANDARD_DEVIATION 9.73 | 25.4 years STANDARD_DEVIATION 10.08 | 29.0 years STANDARD_DEVIATION 9.41 |
| Laterality Left | 19 Participants | 9 Participants | 10 Participants |
| Laterality Right | 26 Participants | 16 Participants | 10 Participants |
| Race and Ethnicity Not Collected | 0 Participants | — | — |
| Sex: Female, Male Female | 13 Participants | 6 Participants | 7 Participants |
| Sex: Female, Male Male | 32 Participants | 19 Participants | 13 Participants |
| Type of Anterior Cruciate Ligament (ACL) Graft Allograft | 3 Participants | 2 Participants | 1 Participants |
| Type of Anterior Cruciate Ligament (ACL) Graft Bone-Patellar Tendon-Bone Autograft | 26 Participants | 15 Participants | 11 Participants |
| Type of Anterior Cruciate Ligament (ACL) Graft Hamstring Tendon Autograft | 10 Participants | 5 Participants | 5 Participants |
| Type of Anterior Cruciate Ligament (ACL) Graft Quadriceps Tendon Autograft | 6 Participants | 3 Participants | 3 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 25 | 0 / 20 |
| other Total, other adverse events | 0 / 25 | 0 / 20 |
| serious Total, serious adverse events | 0 / 25 | 0 / 20 |
Outcome results
Primary
Degrees of Knee Extension
Degrees of knee extension will be measured on the operative side by a licensed physical therapist, with zero degrees indicating the knee completely at extension and negative degrees indicating degrees of hyperextension. The outcome will be reported biweekly and then finally reported as a change in degrees from the first measurement to the final measurement. The results reported in this data table refer to the degrees of knee extension at each reported time point. The change in knee extension results can be found in the statistical analysis section.
Time frame: Tracked in the perioperative week and then from initiation of therapy 2 weeks post-op through 12 weeks post-op.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| BFR Therapy | Degrees of Knee Extension | 4 weeks post-op | -0.32 degrees | Standard Error 0.73 |
| BFR Therapy | Degrees of Knee Extension | 8 weeks post-op | 1.22 degrees | Standard Error 0.64 |
| BFR Therapy | Degrees of Knee Extension | 2 weeks post-op | -3.60 degrees | Standard Error 1.45 |
| BFR Therapy | Degrees of Knee Extension | 10 weeks post-op | 1.62 degrees | Standard Error 0.68 |
| BFR Therapy | Degrees of Knee Extension | 6 weeks post-op | 0.68 degrees | Standard Error 0.51 |
| BFR Therapy | Degrees of Knee Extension | 12 weeks post-op | 1.59 degrees | Standard Error 0.63 |
| BFR Therapy | Degrees of Knee Extension | Perioperative week | -6.88 degrees | Standard Error 1.4 |
| No BFR | Degrees of Knee Extension | 12 weeks post-op | 0.31 degrees | Standard Error 0.6 |
| No BFR | Degrees of Knee Extension | Perioperative week | -5.25 degrees | Standard Error 1.25 |
| No BFR | Degrees of Knee Extension | 2 weeks post-op | -3.20 degrees | Standard Error 0.84 |
| No BFR | Degrees of Knee Extension | 4 weeks post-op | -0.09 degrees | Standard Error 0.89 |
| No BFR | Degrees of Knee Extension | 6 weeks post-op | -0.15 degrees | Standard Error 0.58 |
| No BFR | Degrees of Knee Extension | 8 weeks post-op | 0.63 degrees | Standard Error 0.73 |
| No BFR | Degrees of Knee Extension | 10 weeks post-op | 0.33 degrees | Standard Error 0.67 |
Comparison: This analysis compares the change over time in degrees of knee extension between the BFR Therapy group and the No BFR Group from 2 weeks post-op to 12 weeks post-op. Underlying data was collected on a biweekly basis. This statistical test utilized the null hypothesis that there would be no difference between groups in the change in degrees of knee extension over time.p-value: 0.049t-test, 1 sided
Primary
Degrees of Knee Flexion
Degrees of knee flexion will be measured on the operative side by a licensed physical therapist. The outcome will be reported biweekly and then finally reported as a change in degrees from the first measurement to the final measurement. The results reported in this data table refer to the degrees of knee flexion at each reported time point. The change in knee flexion results can be found in the statistical analysis section.
Time frame: Tracked in the perioperative week and then from initiation of therapy 2 weeks post-op through 12 weeks post-op.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| BFR Therapy | Degrees of Knee Flexion | 10 weeks post-op | 135.35 degrees | Standard Error 2.19 |
| BFR Therapy | Degrees of Knee Flexion | 4 weeks post-op | 102.02 degrees | Standard Error 3.07 |
| BFR Therapy | Degrees of Knee Flexion | 8 weeks post-op | 130.78 degrees | Standard Error 2.74 |
| BFR Therapy | Degrees of Knee Flexion | 6 weeks post-op | 121.08 degrees | Standard Error 2.73 |
| BFR Therapy | Degrees of Knee Flexion | 2 weeks post-op | 76.4 degrees | Standard Error 3.53 |
| BFR Therapy | Degrees of Knee Flexion | 12 weeks post-op | 137.18 degrees | Standard Error 2.2 |
| BFR Therapy | Degrees of Knee Flexion | Perioperative Week | 51.54 degrees | Standard Error 4.43 |
| No BFR | Degrees of Knee Flexion | 12 weeks post-op | 130.50 degrees | Standard Error 2.59 |
| No BFR | Degrees of Knee Flexion | 10 weeks post-op | 130.12 degrees | Standard Error 2.52 |
| No BFR | Degrees of Knee Flexion | 8 weeks post-op | 126.22 degrees | Standard Error 3.34 |
| No BFR | Degrees of Knee Flexion | Perioperative Week | 41.9 degrees | Standard Error 4.22 |
| No BFR | Degrees of Knee Flexion | 2 weeks post-op | 70.00 degrees | Standard Error 5.35 |
| No BFR | Degrees of Knee Flexion | 4 weeks post-op | 91.75 degrees | Standard Error 4.18 |
| No BFR | Degrees of Knee Flexion | 6 weeks post-op | 112.74 degrees | Standard Error 3.74 |
Comparison: This analysis compares the change over time in degrees of knee flexion between the BFR Therapy group and the No BFR Group from 2 weeks post-op to 12 weeks post-op. Underlying data was collected on a biweekly basis. This statistical test utilized the null hypothesis that there would be no difference between groups in the change in degrees of knee flexion over time.p-value: 0.242t-test, 1 sided
Primary
International Knee Documentation Committee (IKDC) Questionnaire Score
The International Knee Documentation Committee (IKDC Questionnaire) is a knee-specific patient-reported outcome measure. The IKDC Questionnaire is a subjective scale that provides patients with an overall function score. The questionnaire looks at 3 categories: symptoms, sports activity, and knee function. Scores are obtained by summing the individual items, then transforming the crude total to a scaled number that ranges from 0 to 100. This final number is interpreted as a measure of function with higher scores representing higher levels of function.
Time frame: Measured preoperatively and at 12 weeks post-op.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| BFR Therapy | International Knee Documentation Committee (IKDC) Questionnaire Score | Preoperative visit | 47.40 score on a scale | Standard Error 8 |
| BFR Therapy | International Knee Documentation Committee (IKDC) Questionnaire Score | 12 weeks post-op | 61.83 score on a scale | Standard Error 2.93 |
| No BFR | International Knee Documentation Committee (IKDC) Questionnaire Score | Preoperative visit | 50.80 score on a scale | Standard Error 4.01 |
| No BFR | International Knee Documentation Committee (IKDC) Questionnaire Score | 12 weeks post-op | 52.86 score on a scale | Standard Error 3.25 |
Comparison: Null hypothesis: there is no difference between groups in IKDC score at 12 weeks post-op.p-value: 0.0219t-test, 1 sided
Primary
Quadriceps Tendon Strength
We will measure quadriceps tendon strength (closed chain) strength using a hand-held dynamometer placed just distal to the knee joint on the posterior calf with the patient in the supine position. The outcome will be reported biweekly as a percentage of the strength of the contralateral side, and then finally reported as a change in strength from the first measurement to the final measurement. The results reported in this data table refer to the percent strength of the operated leg when compared to the contralateral side. The change in strength results can be found in the statistical analysis section.
Time frame: Tracked from initiation of therapy 2 weeks post-op through 12 weeks post-op.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| BFR Therapy | Quadriceps Tendon Strength | Week 2 | 58.88 percent difference to contralateral side | Standard Error 4.45 |
| BFR Therapy | Quadriceps Tendon Strength | Week 4 | 63.68 percent difference to contralateral side | Standard Error 3.37 |
| BFR Therapy | Quadriceps Tendon Strength | Week 6 | 75.73 percent difference to contralateral side | Standard Error 4.11 |
| BFR Therapy | Quadriceps Tendon Strength | Week 8 | 79.39 percent difference to contralateral side | Standard Error 2.07 |
| BFR Therapy | Quadriceps Tendon Strength | Week 10 | 80.22 percent difference to contralateral side | Standard Error 2.89 |
| BFR Therapy | Quadriceps Tendon Strength | Week 12 | 85.47 percent difference to contralateral side | Standard Error 3.84 |
| No BFR | Quadriceps Tendon Strength | Week 10 | 78.41 percent difference to contralateral side | Standard Error 5.11 |
| No BFR | Quadriceps Tendon Strength | Week 2 | 51.35 percent difference to contralateral side | Standard Error 5.85 |
| No BFR | Quadriceps Tendon Strength | Week 8 | 72.88 percent difference to contralateral side | Standard Error 3.16 |
| No BFR | Quadriceps Tendon Strength | Week 4 | 66.13 percent difference to contralateral side | Standard Error 3.43 |
| No BFR | Quadriceps Tendon Strength | Week 12 | 73.03 percent difference to contralateral side | Standard Error 5.31 |
| No BFR | Quadriceps Tendon Strength | Week 6 | 68.51 percent difference to contralateral side | Standard Error 3.33 |
Comparison: This analysis compares the change over time in quadriceps tendon strength between the BFR Therapy group and the No BFR Group. Underlying data was collected on a biweekly basis as the percent difference of the operated knee compared to the contralateral side. This statistical test utilized the null hypothesis that there would be no difference between groups in the change in quadriceps tendon strength over time.p-value: 0.011t-test, 1 sided
Primary
Thigh Circumference
A tape measure will be used to measure the thigh circumference 15 cm proximal to the superior pole of the patella. The outcome will be reported biweekly as a percentage of the contralateral side, and then finally reported as a change in circumference from the first measurement to the final measurement. The results reported in this data table refer to the percent circumference of the operated leg when compared to the contralateral side. The change in circumference results can be found in the statistical analysis section.
Time frame: Tracked in the perioperative week and then from initiation of therapy 2 weeks post-op through 12 weeks post-op.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| BFR Therapy | Thigh Circumference | 6 weeks post-op | 95.33 percent difference to contralateral side | Standard Error 1.05 |
| BFR Therapy | Thigh Circumference | 8 weeks post-op | 96.03 percent difference to contralateral side | Standard Error 0.71 |
| BFR Therapy | Thigh Circumference | Perioperative | 99.23 percent difference to contralateral side | Standard Error 1.65 |
| BFR Therapy | Thigh Circumference | 10 weeks post-op | 96.00 percent difference to contralateral side | Standard Error 0.71 |
| BFR Therapy | Thigh Circumference | 4 weeks post-op | 94.55 percent difference to contralateral side | Standard Error 0.82 |
| BFR Therapy | Thigh Circumference | 12 weeks post-op | 98.28 percent difference to contralateral side | Standard Error 0.61 |
| BFR Therapy | Thigh Circumference | 2 weeks post-op | 97.02 percent difference to contralateral side | Standard Error 1.11 |
| No BFR | Thigh Circumference | 12 weeks post-op | 98.27 percent difference to contralateral side | Standard Error 0.83 |
| No BFR | Thigh Circumference | Perioperative | 101.62 percent difference to contralateral side | Standard Error 2.09 |
| No BFR | Thigh Circumference | 2 weeks post-op | 97.68 percent difference to contralateral side | Standard Error 1.05 |
| No BFR | Thigh Circumference | 4 weeks post-op | 97.11 percent difference to contralateral side | Standard Error 0.94 |
| No BFR | Thigh Circumference | 8 weeks post-op | 95.76 percent difference to contralateral side | Standard Error 1.09 |
| No BFR | Thigh Circumference | 10 weeks post-op | 96.46 percent difference to contralateral side | Standard Error 0.9 |
| No BFR | Thigh Circumference | 6 weeks post-op | 95.55 percent difference to contralateral side | Standard Error 0.91 |
Comparison: This analysis compares the change over time in thigh circumference between the BFR Therapy group and the No BFR Group. Underlying data was collected on a biweekly basis as the percent difference of the operated knee compared to the contralateral side. This statistical test utilized the null hypothesis that there would be no difference between groups in the change in thigh circumference over time.p-value: 0.223t-test, 1 sided
Primary
Visual Analog Score
The visual analog scale (VAS) is a validated, subjective measure for acute and chronic pain. Scores are recorded by making a handwritten mark on a 10-cm line that represents a continuum between no pain and worst pain, with no pain corresponding to a VAS score of 0 and worst pain corresponding to a VAS score of 10.
Time frame: Measured preoperatively, at 2-weeks post-op, 6 weeks post-op, and 12 weeks post-op
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| BFR Therapy | Visual Analog Score | 6 weeks post-op | 1.00 score on a scale | Standard Error 0.26 |
| BFR Therapy | Visual Analog Score | Preoperative visit | 2.36 score on a scale | Standard Error 0.5 |
| BFR Therapy | Visual Analog Score | 2 weeks post-op | 2.72 score on a scale | Standard Error 0.65 |
| BFR Therapy | Visual Analog Score | 12 weeks post-op | 0.29 score on a scale | Standard Error 0.3 |
| No BFR | Visual Analog Score | 12 weeks post-op | 1.16 score on a scale | Standard Error 0.37 |
| No BFR | Visual Analog Score | 6 weeks post-op | 1.51 score on a scale | Standard Error 0.56 |
| No BFR | Visual Analog Score | 2 weeks post-op | 3.16 score on a scale | Standard Error 0.63 |
| No BFR | Visual Analog Score | Preoperative visit | 3.18 score on a scale | Standard Error 1.02 |
Comparison: Null hypothesis: there is no difference between groups in VAS score at 12 weeks post-op.p-value: 0.008t-test, 1 sided
Secondary
Adverse Effects
Observation of any adverse events associated with BFR therapy, such as numbness, cuff-site pain, and bruising.
Time frame: Tracked from initiation of therapy 2 weeks post-op through 12 weeks post-op
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| BFR Therapy | Adverse Effects | 0 adverse events |
| No BFR | Adverse Effects | 0 adverse events |