Electromyostimulation and Strength Walking for Knee Injuries

The purpose of this project is to compare three treatment regimens for knee injury to the standard rehabilitation protocol: 1) NMES, 2) graduated strength walking (via a weighted vest), and 3) NMES combined with graduated strength walking. Each treatment arm will be supplemented by the standard of care and compared to a group who receive the standard rehabilitation only.

The Study will compare the effects of NMES, Strength Walking and combined NMES/ Strength Walking on strength, mobility, symptomatology, and Quality of Life (QOL) in military members with knee injury to a standard rehabilitation protocol program only. All groups will participate in standard rehabilitation protocol. The groups will be assessed over 18 weeks to compare main and interactive effects over time.

The prevalence of knee injuries has shown a striking increase of \>24% over the last 5 years, affecting work performance, limiting mobility, and impacting military deployment health. This increase reflects the current high op-tempo and frequent deployments of a nation at war including activities related to military operations, physical fitness, and demanding training. We have shown that neuromuscular electrical stimulation (NMES) improves quadriceps muscle strength. We have also shown that a pedometer-based protocol improves fitness. The overall objective of this project is to compare three treatment regimens for knee injury to the standard rehabilitation protocol as potential treatments for improving strength, work efficiency, and mobility in active duty military personnel with a knee injury. Our central hypothesis is that the combination of NMES and walking while wearing a weighted vest will demonstrate greater improvements in muscle strength, work efficiency, and mobility, as compared to the usual care alone. The rationale is that NMES combined with graduated strength walking could produce marked improvements in muscle strength and thereby enhance work performance, readiness and fitness, decrease physical symptoms and faster return to duty. NMES and graduated strength walking, simulate the current uniform in the theatre of operation (body armor).The specific aims are to compare the effectiveness of three treatment regimens to the usual care in improving: (1) muscle strength, (2) work efficiency, (3) mobility, (4) symptoms/pain, and (5) quality of life. After baseline testing, we propose to randomly assign male and female subjects (n=132) ages 18 to 50 years with a knee injury to one of 4 groups: 1) NMES, 2) strength walking, 3) NMES and strength walking, or 4) usual care. All groups will receive 12-weeks of the intervention and 6-weeks of follow-up. Generalized estimating equation (GEE) methods will be used to build regression models for statistical analysis of longitudinal data. If the interventions are effective with respect to parameters of strength, mobility, work performance, and symptoms, recommendations for future treatments can be made. This is hugely important, given the rising rate of knee injuries and the possibility that provider-managed care would be critical for assisting our warriors in a rapid recovery and return to duty.

Eligibility Criteria:
Inclusion Criteria:

* A diagnosis of knee injury (internal derangement of the knee with new effusion, including knee sprain or strains, meniscal tear, cruciate ligamentous tear, and chondral flap or injury);
* A diagnosis of knee pain that is anterior knee pain, overuse pain, patella-femoral pain, and chronic pain (less than 6 months) associated with overuse syndromes which negatively impacts performance by (a) pain in 1 or both knees on most days of the month; b) self reported difficulty performing at least one or more tasks due to pain: stair climbing, rising from a chair, walking or running a quarter mile, repetitive movements such as kneeling or squatting or stooping, pain that inhibits job performance and daily activities;
* Military service member at the time of injury (active duty military and Reserve/ National Guard in active duty status);
* Age ≥18 and ≤50 years;
* Ability to provide freely given informed consent.

Exclusion Criteria:

* Fracture or injury to external knee structures such that knee extension or flexion is impaired;
* Evidence of a fracture on radiographs or clinical evidence of unstable tendon tear/rupture;
* A significant co-morbid medical condition (such as severe hypertension or neurological disorder in which NMES strength training or unsupervised exercise is contraindicated and would pose a safety threat or impair ability to participate;
* Inability or unwillingness to participate in a walking or strengthening program;
* Inability to speak and/or read English;
* Reduced sensory perception in the lower extremities;
* Inability to walk on a treadmill without an assistive device;
* Vision impairment, where participant is classified as legally blind;
* Unwillingness to accept random assignment;
* Pregnancy;
* A score of 23 or greater on the Center for Epidemiological Studies- Depression scale (CES-D);
* If the person has a demand type implanted pacemaker or defibrillator.