Trial of Self-managed Approaches for Patellofemoral Pain Syndrome in Active Duty

Patellofemoral pain syndrome (PFPS) is the most common diagnosis among active duty military
presenting with knee pain in the military ambulatory care setting. The incidence of PFPS has
shown a striking increase of >11.3% over the last 4 years, affecting work performance,
limiting activity, and impacting military deployment health. The investigators have shown
that home-based neuromuscular electrical stimulation (NMES) is safe, portable, easy-to-use
and improves quadriceps muscle strength with some pain relief. NMES and transcutaneous
electrical nerve stimulation (TENS) devices are widely used by warfighters in the theatre of
operation for knee problems. The overall objective of this project is to compare three
home-managed treatment regimens for PFPS: NMES, TENS, and NMES combined with TENS to a
standard home exercise program (HEP). The central hypothesis is that the combination of NMES
with TENS will show significantly greater improvements in muscle strength, mobility, pain,
daily activity and quality of life (QOL) than HEP alone. The rationale for this study is that
increasing muscle strength and decreasing pain will significantly improve mobility, physical
activity and QOL. Such outcomes will ultimately result in improved deployability, retention
of military personnel and decreased economic costs in this population. The specific aims are
to determine whether the three treatment regimens are significantly more efficacious than
standard HEP for improving muscle strength, physical activity, mobility, QOL and symptoms of
PFPS including pain. After consent and baseline testing, the investigators will randomly
assign active duty male and female subjects, ages 18 to <45, (n=136) with PFPS to one of the
four groups. Each of the three treatment arms will be supplemented by HEP and compared to a
group receiving standard HEP alone. All groups will receive 9 weeks of home therapy. Using
GEE methods, the investigators will build longitudinal regression models so that differences
in time trends for the outcome variables among controls and those in the treatment groups can
be statistically assessed. Positive results could translate into accelerated rehabilitation,
decreased symptoms and lower medical costs with better patient outcomes.

Inclusion Criteria:

The study will be open to all active duty personal who are:

1. diagnosed with knee pain, categorized as anterior or retropatellar in one or both
knees;

2. self-reported difficulty performing at least two or more of the following activities
associated with knee pain: prolonged sitting, stair climbing, running, jumping and
repetitive movements such as kneeling or squatting or stooping;

3. military service member at the time of diagnosis;

4. age ≥18 and <45 years; and

5. ability to provide freely given informed consent.

Exclusion Criteria:

Those who might be at risk of adverse outcomes from the study interventions will be
excluded. This includes individuals with

1. Fracture or injury to external knee structures such that knee extension or flexion is
impaired;

2. A significant co-morbid medical condition (such as severe hypertension, neurological
disorder or pacemaker/defibrillator) in which NMES strength training or unsupervised
exercise is contraindicated and would pose a safety threat or impair ability to
participate;

3. Previous knee surgeries (i.e., tibiofemoral, patellofemoral) excluding knee
arthroscopy;

4. Knee instability or recurrent patella dislocation or subluxation;

5. Inability or unwillingness to participate in a home exercise program or strengthening
program;

6. Inability to speak and/or read English;

7. Reduced sensory perception in the lower extremities;

8. Pregnancy;

9. Vision impairment, where participant is classified as legally blind;

10. Unwillingness to accept random assignment; or

11. A score of 23 or greater on the Center for Epidemiological Studies-Depression scale
(CES-D).