Muscle Strengthening and Return-to-exercise Criteria After Anterior Cruciate Ligament Reconstruction (ACLR)

Study Overview
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Brief Summary
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Anterior cruciate ligament injury is very common in recreational and elite athletes. It is considered the second most frequent pathology seeing in Sports Medicine Services. After the injury and ACLR, there is a marked decrease in the strength of the knee extensors/flexors muscles. Strength exercise programs are aimed at recovering strength and functionality, however, a low percentage of patients manage to achieve the optimal return-to-exercise criteria. Therefore, it is relevant to design and evaluate exercise programs that allow early recovery of muscle strength and knee functionality. The main purpose of this study is to investigate a neuromuscular exercise program compared with a standard institutional program in the recovery of the strength and functionality of the knee extensor/flexor muscles after ACLR.

Detailed Description
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Study design: this is a 22-week, randomized trial. 62 participants will be recruited from the medical services of the National Institute of Rehabilitation (NIR). Participants: adults between 20-40 years old, with a body mass index <30.0 kg/mˆ2, history of sports practice immediately prior to the injury, post-operated unilaterally for ACL with the hamstring autograft technique (semitendinosus-gracilis tendons), with full ranges of motion and no edema will be recruited. Participants with multi-ligament knee injuries, with more than 12 months from the injury to surgery or more than 8 months after surgery, with uncompensated metabolic diseases or acute illnesses/infections under treatment will not be recruited. Intervention: participants will be randomized to 1) neuromuscular or 2) institutional exercise program with computer-generated random numbers. Both programs consist of isotonic open and closed kinetic chain exercises for the hip and knee. The neuromuscular program also includes exercises to improve vastus medialis and lateralis strength, hamstrings, hip flexors and extensors, proprioception, and core stability. On the other hand, the institutional program includes concentric and eccentric knee exercises. Both programs will be performed 3 days/week, 3 sets, 18-22 repetitions for each exercise; the intensity will initiate at 65-75% (1RM), and it will be increased to 75-85%; the workload will be increased 5-10% from the fifth week according to perceived exertion. The exercises will be done with both legs; however, the injured leg will be exercised complementary. The last 6 weeks of the programs correspond to functional exercises according the sport. Every training session will consist of 15 minutes of warm-up, 40-60 minutes of resistance training, and 15 minutes of cool-down; all training sessions will take place in the NIR Sports Medicine therapeutic gym. The knee flexors/extensors muscle strength will be determined by isokinetic dynamometry (at 60°/s). The knee function will be evaluated by hop tests and agility T-test. The patient's perception of daily functional activities after ACL reconstruction will be assessed by the Lysholm knee score. For each participant, the study length will be 22 weeks with 66 exercise sessions. The beginning of the study corresponds to session 1 of exercise. Initial evaluation will be performed 5 days prior to the start of the intervention, while final evaluations will be conducted at the end of 22 weeks of follow-up (2 days after the last day of the intervention). Data will be recorded by study investigators.

Official Title
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Comparison of Two Muscle Strengthening Programs on the Return-to-exercise Criteria in Patients With Anterior Cruciate Ligament Reconstruction

Conditions
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Anterior Cruciate Ligament Injuries

Intervention / Treatment
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* Other: Neuromuscular exercise program
* Other: Institutional exercise program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: History of sports practice immediately prior to the injury Post-operated unilaterally for ACL with the hamstring autograft technique (semitendinosus-gracilis tendons), Full ranges of motion and no edema Body mass index < 30.0 kg/mˆ2 Exclusion Criteria: Multi-ligament knee injuries, More than 12 months from the injury to surgery More than 8 months after surgery Uncompensated metabolic diseases Acute illnesses/infections under treatment

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 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 |
| --- | --- |
| Experimental: Neuromuscular exercise program<br>Participants on a neuromuscular exercise program | Other: Neuromuscular exercise program<br>* Participants will complete a neuromuscular program during 22 weeks. The program consist of isotonic open and closed kinetic chain exercises for the hip and knee, and training to improve hip and knee muscles strength, proprioception, and core stability.<br>|
| Active Comparator: Institutional exercise program<br>Participants on an institutional exercise program | Other: Institutional exercise program<br>* Participants will complete an institutional exercise program during 22 weeks. The program consist of isotonic open and closed kinetic chain exercises for the hip and knee, and concentric and eccentric knee exercises.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Knee flexors muscle strength asymmetry | The asymmetry will be calculated as the percentage of the peak knee flexor torque in the involved limb over the peak knee flexor torque in the uninvolved limb, multiplied by 100. Asymmetry % = (peak flexor torque involved limb/ peak flexor torque uninvolved limb) *100 | 22 weeks | 
| Knee extensors muscle strength asymmetry | The asymmetry will be calculated as the percentage of the peak knee extensor torque in the involved limb over the peak knee extensor torque in the uninvolved limb, multiplied by 100. Asymmetry % = (peak extensor torque involved limb/peak extensor torque uninvolved limb)*100 | 22 weeks | 
| Hop distance asymmetry | The asymmetry will be calculated as the percentage of the hop distance (one leg hop, triple hop, or cross-over hop) in the involved limb over the hop distance in the uninvolved limb, multiplied by 100. Asymmetry % = (hop distance involved limb/hop distance uninvolved limb)*100 | 22 weeks | 
| Agility T-test time | The time will be determined with data obtained from T-test; the fastest time will be recorded. | 22 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg muscle quality index (MQIleg) | The muscle quality index from legs will be calculated with data obtained by isokinetic dynamometry, and lean mass obtained by bioimpedance analysis . MQIleg = peak torque (Nm) / leg lean mass (kg) | Baseline and 22 weeks | 
| Lysholm knee score | The score consists of eighth questions rated to produce an overall score on a point scale of 0 to 100. An assignment is given as excellent for 95 to 100 points, good for 84 to 94 points, fair for 66 to 83 points, and poor for less than 65 points. | Baseline and 22 weeks |