Combined NMES and BFR Training After TKA
Condition: Total Knee Arthroplasty
Study type: Interventional

Summary: 
      The purpose of this feasibility study is to determine the initial efficacy of early combined
      Neuromuscular Electrical Stimulation (NMES) and Blood Flow Restriction (BFR) in addition to
      standard rehabilitation in 15 subjects after Total Knee Arthroplasty (TKA). The second aim is
      to determine the feasibility and patient perceptions of combined NMES and BFR by assessing:
      1) adherence, 2) satisfaction and 3) safety.
    

Detailed description: 
      It's estimated that almost 3.5 million Total Knee Arthroplasties (TKA) will be performed
      annually by 2030. Despite initiating rehabilitation within 48 hours of surgery, up to a 60%
      strength loss is noted in the quadriceps one month after TKA. This weakness persists for
      years after surgery and is associated with decreased gait speed, balance, stair climbing
      ability and is associated with an increased risk for falls. Approximately 85% of the strength
      loss after TKA is explained by the combination of voluntary muscle activation deficits and
      muscle atrophy. Immediately postoperatively, strength loss is primarily due to activation
      deficits, and as time progresses, muscle atrophy becomes the major contributing factor. Early
      in the postoperative period, Neuromuscular Electrical Stimulation (NMES) has been shown to
      diminish activation deficits and improve function after TKA. Blood Flow Restriction (BFR) is
      a proposed strength training alternative for people who are unable to tolerate traditional
      strength training at 70-80% of their 1 repetition maximum (1RM), such as those who have just
      had surgery. Performing low intensity exercise (20-30% of 1RM) with BFR has been shown to
      achieve similar muscle mass and strength gains when compared to high intensity resistance
      training. BFR has been studied in people with TKA, but it has been used later in the recovery
      period (>6 weeks postoperative) when the greatest strength losses have already occurred. The
      goal of this study is to address both factors of postoperative quadriceps weakness,
      activation deficit and atrophy, through the use of early NMES and BFR in addition to standard
      postoperative rehabilitation in an attempt to minimize strength loss and improve functional
      outcomes.

      AIM 1: To determine the initial efficacy of combined neuromuscular electrical stimulation and
      blood flow restriction training (COMBO) on strength (primary outcome), activation, pain,
      range of motion, and function compared to historical controls.

      Hypothesis 1.1: The COMBO group will have greater attenuation of early postoperative strength
      losses and improved pain, ROM, and function compared to historical controls.

      AIM 2: To determine the feasibility of COMBO by assessing 1) adherence, 2) satisfaction, and
      3) safety

      Hypothesis 2.1: An 80% adherence rate to the intervention will be observed.

      Hypothesis 2.2: Study participants will indicate acceptability of COMBO with a satisfaction
      survey median score of at least 4/5 ("somewhat satisfied").

      Hypothesis 2.3: There will be no intervention-related Adverse Events or Serious Adverse
      Events during the 8-week protocol.
    

Intervention name(s): Standard Rehabilitation + Neuromuscular Electrical Stimulation and Blood Flow Restriction
Intervention type(s): Procedure
Intervention description(s): Subjects will begin a standardized protocol on post-op day 2. Outpatient visits will be 2x/wk for weeks 0-4 and then 1x/wk for weeks 5-8.
Subjects will utilize NMES on the quadriceps in the home setting 2x/day for the first 3-4 weeks during isometric contractions at their highest tolerated intensity. Total treatment will begin at 10 minutes.
At the end of post-op week 2, subjects will be exposed in clinic to BFR on the surgical limb increasing to 80% limb occlusion pressure over weeks 3-4 as tolerated. Initially, BFR and NMES will be performed simultaneously. BFR will then be progressed using active exercises. After completing a safety checklist, subjects will be issued a home BFR unit for use 2x/week (3x total including clinic visit) at which time NMES will be discontinued. BFR exercise intensity will be progressed as tolerated to maintain 20-30% of 1RM.
Other intervention name(s): Blood Flow Restriction; Occlusion Training; BFR; Neuromuscular Electrical Stimulation; NMES
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Blood Flow Restriction; Neuromuscular Electrical Stimulation; BFR; NMES; Rehabilitation