Characterizing Clinical and Biomechanical Contributions to Function Following ACL Reconstruction

Study Overview
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Brief Summary
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Quantify differences in quadriceps function and gait biomechanics in individuals within 2 years of ACL reconstruction compared to a healthy comparison group and establish the feasibility of conducting a progressive strengthening program to improve clinical and patient-oriented outcomes in individuals who are within 2 years of ACL reconstruction

Detailed Description
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A maximal isometric muscle contraction of the quadriceps will be used to examine neural and peripheral contributions to quadriceps strength. Neural influences will be quantified using the interpolated twitch technique (voluntary activation) and early RTD. Peripheral influences will be quantified by examining the stimulus-evoked torque with the quadriceps relaxed (resting twitch) and late RTD. Knee joint biomechanics during treadmill walking and running will include sagittal plane (flexion, extension) movement variability (Lyapunov Exponent and approximate entropy), peak knee flexion angle, and peak external knee flexion and adduction moments. Additionally, the clinical relevance of impairments in the ACL reconstruction group will be determined by examining the relationship with performance on jumping tasks and patient function (secondary outcomes). The progressive strengthening program will be performed for 6 weeks and emphasize development of strength and power. Feasibility will be established if the researchers can recruit up to 8 participants and retain at least 80% over the 3 week intervention program. The researchers will determine effect sizes for changes outcome measures.

Official Title
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Characterizing Clinical and Biomechanical Contributions to Function Following ACL Reconstruction

Conditions
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ACL Tears

Intervention / Treatment
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* Other: Progressive strengthening program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Physically active History of primary unilateral ACL reconstruction within the past 3-24 months (ACL group only) Exclusion Criteria: History of lumbar spine or lower extremity injury or surgery (except ACL) within the past 1 year that required physician care Concomitant knee injury (ACL group only): ligament injury that requires surgical repair (medial collateral ligament [MCL], posterior cruciate ligament[PCL]), chondral defects >2cm, fracture, bilateral knee injury Medial conditions that are contraindications to electrical stimulation: Cardiac Pacemaker and Pregnancy Participants who are unable to understand procedures of experiment or provide consent (assent/parental permission)

Ages Eligible for Study
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Minimum Age: 14 Years
Maximum Age: 35 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: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: Physical therapy exercises (progressive strengthening program)
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Progressive strengthening program<br>Subjects identified as having a clinically relevant strength deficit will be asked to participate in physical therapy sessions 3 times per week for 3 weeks. The strengthening program will consist of an individualized, progressive exercise program with an emphasis on increasing lower extremity strength, power, and biomechanics. | Other: Progressive strengthening program<br>* The progressive strengthening program will be performed for 3 weeks and emphasize development of strength and power. Feasibility will be established if we can recruit up to 8 participants and retain at least 80% over the 3 week intervention program. We will determine effect sizes for changes outcome measures.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quadriceps Rate of Torque Development (RTD) Maximum | slope of the torque-time tracing (change in torque/change in time) (Nm/kg*s-1) | Change from Baseline Quadriceps RTD at 3 weeks | 
| Knee Joint biomechanics during gait (nonlinear) | Sagittal plane (knee flexion) movement variability (calculated using Lyapunov Exponent and approximate entropy) | Change from Baseline nonlinear knee joint biomechanics at 3 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quadriceps percent activation | Supramaximal electrical stimulus (interpolated twitch technique) used to augment a voluntary muscle contraction | Change from Baseline Quadriceps percent activation at 3 weeks | 
| Knee Joint biomechanics during gait (traditional) | peak external knee flexion moment (Nm/kgm) | Change from Baseline knee joint biomechanics at 3 weeks | 
| Patient reported function | International Knee Documentation Committee (IKDC) subjective form | Change from Baseline IKDC at 3 weeks | 
| Jumping performance | single leg hop for distance (cm) | Change from Baseline single leg hop for distance at 3 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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quadriceps strength, quadriceps voluntary activation, progressive strength program