Trial of Neurostimulation and Blood Flow Restriction for PFPS in Active Duty
Condition: Patellofemoral Pain Syndrome
MeSH terms: Patellofemoral Pain Syndrome
Study type: Interventional

Summary: 
      The overall objective of this project is to compare two self-managed treatment regimens for
      PFPS: (1) NMES-Exercise supplemented with high BFR LOP of 80% and (2) NMES Exercise augmented
      with a low percentage of BFR LOP at 20 mmHG (BFR-sham). Each of the two treatment arms will
      perform a fixed exercise protocol singularly and in combination with BFR-NMES, and NMES
      alone. The specific aims of the study are 1) To determine whether self-managed NMES-Exercise
      program supplemented with a high BFR of 80% LOP (limb occlusion pressure) is significantly
      more efficacious than NMES-Exercise with low BFR LOP set at 20 mmHG (sham) in improving
      muscle strength of the lower extremity, daily physical activity and mobility; and 2) To
      determine whether NMES-Exercise with high LOP BFR therapy improves QOL and PFPS symptoms
      significantly more than NMES-Exercise with low LOP BFR.
    

Detailed description: 
      The long-term goal is to identify effective self-managed therapies for military members that
      will return them to duty as quickly as possible. The overall objective of this project is to
      compare two self-managed treatment regimens for PFPS: (1) NMES-Exercise supplemented with
      high BFR LOP of 80% and (2) NMESExercise augmented with a low percentage of BFR LOP at 20
      mmHG (BFR-sham). Each of the two treatment arms will perform a fixed exercise protocol
      singularly and in combination with BFR-NMES, and NMES alone.

      The rationale for this study is that by limiting blood flow to an exercising limb using both
      active and passive exercise is expected to significantly improve lower extremity muscle
      strength, mobility, quality of life (QOL) and pain. The central hypothesis is that the
      combination of NMES/exercise of the injured leg supplemented with BFR set at 80% LOP will
      show significantly greater improvements in muscle strength, mobility, pain, daily activity
      and QOL than the NMES-Exercise with BFR set at a very low percentage of LOP at 20 mmHG. To
      test this hypothesis, the investigators will address the following specific aims:

      a1. To determine whether self-managed NMES-Exercise program supplemented with a high BFR of
      80% LOP (limb occlusion pressure) is significantly more efficacious than NMES-Exercise with
      low BFR LOP set at 20 mmHG (sham) in improving muscle strength of the lower extremity, daily
      physical activity and mobility. Muscle strength will be measured by isometric peak torque of
      the left and right knee and hip posterolateral stabilizers; physical activity will be
      measured by steps walked and energy (kcal) expenditure/day; and mobility by time to complete
      a stair climb, step down test, distance walked in 6 minutes, and number of times to complete
      the chair rise.

      a2. To determine whether NMES-Exercise with high LOP BFR therapy improves QOL and PFPS
      symptoms significantly more than NMES-Exercise with low LOP BFR. QOL will be measured by the
      SF-12 Health Survey and the Center for Epidemiological Studies-Depression (CES-D) scale.
      Symptoms of PFPS will be quantified by the Anterior Knee Pain Scale and IKDC subjective knee
      form.

      The investigators expect to demonstrate that these combined multimodality therapies of a
      self-managed NMES-Exercise program supplemented with high (80%) LOP BFR-NMES-Exercise is more
      efficacious than a low percentage of LOP BFR-NMES-Exercise (sham). Positive results will
      translate into therapy options for PFPS that can be used by health care providers to
      accelerate rehabilitation, speed return to world-wide duty status, decrease symptoms, and
      lower medical costs. Moreover, these approaches are safe, easy to use and
      non-pharmacological.
    

Intervention name(s): NMES and exercise supplemented with high BFR; NMES and exercise supplemented with low BFR
Intervention type(s): Device; Device
Intervention description(s): The BFR-NMES-Exercise training consists of 20-min sessions performed concurrently with NMES and exercise in the clinic 2x a week for a total of 18 in-clinic sessions. Using the Delfi PTS Personalized Tourniquet System for Blood Flow Restriction at 80% of LOP, the participant performs 4 exercise sets of 60 repetitions (5 seconds ea) for 5 minutes, with a 1-minute BFR deflation between sets. The standard exercise rehabilitation protocol for PFPS combines open chain and closed chain quadriceps strengthening exercises: active straight leg raises, quadriceps straightening, step up, and squats. NMES training consists of 20-minute sessions: a 2-min warm-up, 15-min work-out, and a 3-min cool down using the KneeHAB® XP "Multipath" stimulation system which changes the current pathways between the electrodes for preset periods within each pulse, allowing for higher stimulation intensities that maximizes muscle fibre recruitment and minimizes muscle fatigue.; The BFR-NMES-Exercise training consists of 20-min sessions performed concurrently with NMES and exercise in the clinic 2x a week for a total of 18 in-clinic sessions. Using the Delfi PTS Personalized Tourniquet System for Blood Flow Restriction at 20mmHG venous pressure (no blood flow restricted), the participant performs 4 exercise sets of 60 repetitions (5 seconds ea) for 5 minutes, with a 1-minute BFR deflation between sets. The standard exercise rehabilitation protocol for PFPS combines open chain and closed chain quadriceps strengthening exercises: active straight leg raises, quadriceps straightening, step up, and squats. NMES training consists of 20-minute sessions: a 2-min warm-up, 15-min work-out, and a 3-min cool down using the KneeHAB® XP "Multipath" stimulation system which changes the current pathways between the electrodes for preset periods within each pulse, allowing for higher stimulation intensities that maximizes muscle fibre recruitment and minimizes muscle fatigue.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: 84 (anticipated) participants will be assigned to one of two parallel groups. Sample size was determined using 1) an alpha level of 0.05 and power of 0.80; 2) review of PFPS literature and data from pilot work; and 3) calculation of effect sizes for key variables from previous studies that addressed the Specific Aims.
For the primary outcome variable of strength, the sample size calculated was 35 subjects per groups (70 total subjects) with an effect size of 0.52. For the outcomes measures of function, mobility and pain, assuming that standard errors will be similar to those observed in our previous work, the sample size of 35 per group is sufficient to detect the expected mean changes. To account for dropouts, the investigators inflated the sample size by 20%, for a total of 42 subjects per group and a total sample size of 84.
Masking: None (Open Label)
Primary purpose: Treatment