Dynamic Muscular Electrical Stimulation Following Anterior Cruciate Ligament Reconstruction in Military Academy Cadets

Anterior cruciate ligament (ACL) tears have a recovery time of nearly 6-12 months with operative treatment. While most service members return to full duty after ACL reconstruction, it is delayed by quadriceps activation, muscle weakness, and abnormal gait patterns. Neuromuscular electric stimulation devices are already being used in physical therapy to complement gains in muscle strength and size. The innovation of KneeStim, is that it can be used to stimulate knee muscles while the individual is engaging in their daily activities. This study looks at the effects of 12 weeks of post-operative use of the KneeStim on biomechanical function (gait) in United States Military Academy Cadets aged 17-27 years of age. The investigators hypothesize that using the KneeStim will accelerate normalization of the biomechanical function parameters of gait and thus return to full duty.

• KneeStim (Device): Participant will be randomized to either be in control or experimental group

Primary outcomes

• Change in gait post-operatively assessed by the KneeStimTM Device [6 weeks;3, 6, 9, 12 months post-operative]: Effects of a novel wearable electrical stimulation knee sleeve device (KneeStim) on post-operative biomechanical function (femur sagittal angle, tibial sagittal angle, femur coronal angle, tibial coronal angle, femur and tibia coronal velocity)

Secondary outcomes

• change in gait post-operatively assessed by 3D Motion capture [3, 6, 9, 12 months post-operative]: Kinetic and kinematic biomechanical data will be monitored throughout the return to run phases of rehabilitation in knee and hip joints (walking and running); changes in gait speed (walking and running); changes in join angle range of motion (walking and running); changes in stride length (walking and running)
• change in gait post-operatively assessed by force plate instrumented treadmill [3, 6, 9, 12 months post-operative]: Ground reaction forces will be recorded simultaneously with the motion capture system via force plates on an instrumented treadmill to determine force output between limbs during walking and running trials.
• change in muscle volume assessed by MRI [pre-operative, 3, 6, 9, 12 months post-operative]: Summation of the cross-sectional area and volumetric measurements
• ACL graft healing assessed by MRI [pre-operative, 3, 6, 9, 12 months post-operative]: Signal intensity will be used to monitor tissue quality throughout healing process
• Change in isometric muscle strength assessed by CSMi HUMAC NORM [3, 6, 9, 12 months post-operative]: Rate of torque development (in ms) over time.
• Change in skeletal muscle mass assessed by bioelectrical impedance analysis (SECA BIA) [pre-operative, 4, 8 weeks; 3, 6, 9, 12 months post-operative]: Skeletal muscle mass will be measured (in kg) to monitor rate of muscle hypertrophy/atrophy over rehabilitation timeline.
• Change in lean body mass assessed by bioelectrical impedance analysis (SECA BIA) [pre-operative, 4, 8 weeks; 3, 6, 9, 12 months post-operative]: Muscle mass, bone mass, and body fluid (kg/m2) will be measured to contribute to Body Mass Index (BMI) scores.
• Change in fat mass assessed by bioelectrical impedance analysis (SECA BIA) [pre-operative, 4, 8 weeks; 3, 6, 9, 12 months post-operative]: Fat mass (kg/m2) will be measured to contribute to body mass index (BMI) scores.
• Change in knee pain and function assessed by the Knee Injury and Osteoarthritis Score (KOOS) [pre-operative, 3, 6, 9, 12 months post-operative]: The KOOS is a self-reported outcome measure assessing the patient's perspective about the health, symptoms, and functionality of their knee. It is a 42-item questionnaire, including 5 subscales: symptoms, pain, activities of daily living, function in sports/recreation, and quality of life. A likert scale is used and all items have five possible answers ranging from 0 (no problems) to 4 (extreme problems). The five subscale scores are calculated as the sum of the items for each subscale. Scores are then transformed to a 0-100 scale, with 0 representing extreme knee problems and 100 representing no knee problems.
• Change in knee pain and function assessed by the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) [pre-operative, 3, 6, 9, 12 months post-operative]: The IKDC is a self-reported outcome measure that assesses knee disability and function before and after treatment. It consists of 18 items that measure symptoms, function, and sports activity. Response types include 5-point Likert Scales, 11-point Likert scales, and dichotomous "yes-no" responses.
• Change in knee pain assessed by the Patient-Reported Outcome Measure Information System (PROMIS-29) [pre-operative, 3, 6, 9, 12 months post-operative]: PROMIS-29 is a self-reported outcome measure assessing for the patient's pain intensity. It is a 28-item questionnaire, which includes 7 subscales of four items each: physical function, fatigue, pain interference, depressive symptoms, anxiety, ability to participate in social roles and activities, and sleep disturbance. A likert scale is used for all domain response scales, however they vary in responses.
• Change in knee function assessed with the Single Assessment Numeric Evaluation Method (SANE) [pre-operative, 3, 6, 9, 12 months post-operative]: Participants will provide a numerical rating from 0 (least normal) to 100 (most normal) of the perceived improvement in knee health in relation to their pre-injury baseline.
• Change in knee function assessed by the Marx Activity Rating Scale (MARS) [pre-operative, 3, 6, 9, 12 months post-operative]: MARS includes 4 items that assess the frequency of running, cutting, decelerating, and pivoting based on the subjects "healthiest and most active state in the past year". Each item is scored on a 5-point ordinal scale ranging from 0 (less than 1 time in a month) to 4 (4 or more times in a week), and the total scale score is obtained by summing the individual items' scores (range, 0-16). A higher score indicates more functional demand on the knee joint and potentially a higher risk of injury.
• Impact of ACL surgery on overall quality of life assessed by the Anterior Cruciate Ligament-Quality of Life (ACL-QOL) [pre-operative, 3, 6, 9, 12 months post-operative]: The questionnaire consists of 32 equally weighted questions that are answered using a 100 mm visual analog scale and is scored of 100. It comprises 5 domains, including (1) symptoms and physical complaints (5 items); (2) work-related concerns (4 items); (3) recreational activity and sport participation or competition (12 items); (4) lifestyle (6 items); and (5) social and emotional (5 items).
• Change of running gait function from the patients' perspective assessed by the University of Wisconsin Running Injury and Recovery Index (UWRI) [pre-operative, 3, 6, 9, 12 months post-operative]: The 9-item UWRI assesses running ability following a running related injury, with the maximum score of 36 indicating a return to preinjury running ability.
• Change of knee pain from the patients' perspective assessed by the Visual Analog Scale (VAS) [Weekly from 1-week post-operative until 3 months; monthly from 4-12 months]: Will measure average knee pain over a given timeframe from 0 to 10 cm visual analogue scale where 0 cm equals no pain and 10 cm indicates the most severe pain the patient could imagine. Higher numbers equal greater levels of reported pain.
• Time to return to full duty [12 months post-operative]: Measured by the time from post-operative timepoint to time of full clearance for military tasks
• Difference between the Tindeq Progessor and CSMi HUMAC NORM in measuring peak isometric knee extensor torque. [At either month 3, 6, 9, or 12, Tindeq testing will occur 24-72 hours after the bilateral strength assessment using the CSMi HUMAC NORM.]: Peak isometric extensor torque (nm/kg).
• Difference between the Tindeq Progessor and CSMi HUMAC NORM in measuring knee extensor rate of torque development. [At either month 3, 6, 9, or 12, Tindeq testing will occur 24-72 hours after the bilateral strength assessment using the CSMi HUMAC NORM.]: Rate of torque development (nm/s)

Sex: All, ages: 17 Years to 27 Years

Inclusion Criteria:

1. United States Military Academy cadet between ages of 17-27 years
2. Undergoing a Primary ACL Reconstruction, or Revision ACL Reconstruction

Exclusion Criteria:

1. Concomitant or prior high tibial osteotomy (HTO)
2. Concomitant or prior cartilage restoration procedure
3. Concomitant ligamentous reconstruction (lateral collateral ligament; posterior cruciate ligament; medial collateral ligament)
4. Contraindications to using the KneeStim device

   \- Use of pacemaker, defibrillators, or other implanted electronic devices, as this may cause electric shock, burns, electrical interference, or death Unstable angina or decompensated heart failure Epilepsy or history of seizure disorder Pregnancy or planning to become pregnant (Self reported) Critical ischemia of lower limbs Moderate to severe dementia Altered sensation at the knee such that the user cannot feel a pinprick Undiagnosed pain syndromes
5. Any meniscus tear precluding weight bearing for 6 weeks.

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• Shawn M Gee, MD, Principal investigator, Keller Army Community Hospital