title: Blood Flow Restriction Training After Knee Arthroscopy: A Randomized Controlled Pilot Study.
abstract: BACKGROUND
  Quadriceps strength after arthroscopic knee procedures is frequently diminished several years postoperation. Blood flow restriction (BFR) training uses partial venous occlusion while performing submaximal exercise to induce muscle hypertrophy and strength improvements. The purpose of this study was to evaluate BFR as a postoperative therapeutic intervention after knee arthroscopy.
  
  
  METHODS
  A randomized controlled pilot study comparing physical therapy with and without BFR after knee arthroscopy was conducted. Patients underwent 12 sessions of supervised physical therapy. Subjects followed the same postoperative protocol with the addition of 3 additional BFR exercises. Outcome measures included thigh girth, physical function measures, Knee Osteoarthritis Outcome Score (KOOS), Veterans RAND 12-Item Health Survey (VR12), and strength testing. Bilateral duplex ultrasonography was used to evaluate for deep venous thrombosis preintervention and postintervention.
  
  
  RESULTS
  Seventeen patients completed the study. Significant increases in thigh girth were observed in the BFR group at 6-cm and 16-cm proximal to the patella (P = 0.0111 and 0.0001). All physical outcome measures significantly improved in the BFR group, and the timed stair ascent improvements were greater than conventional therapy (P = 0.0281). The VR-12 and KOOS subscales significantly improved in the BFR group, and greater improvement was seen in VR-12 mental component score (P = 0.0149). The BFR group displayed approximately 2-fold greater improvements in extension and flexion strength compared with conventional therapy (74.59% vs 33.5%, P = 0.034). No adverse events were observed during the study.
  
  
  CONCLUSIONS
  This study suggests that BFR is an effective intervention after knee arthroscopy. Further investigation is warranted to elucidate the benefits of this intervention in populations with greater initial impairment.
authors.affiliation: *Department of Orthopaedics and Rehabilitation, San Antonio Military Medical Center, Ft Sam, Houston, Texas; and †Center for the Intrepid, San Antonio Military Medical Center, Ft Sam, Houston, Texas.
authors.forename: David J
authors.initials: DJ
authors.lastname: Tennent
authors.forename: Christina M
authors.initials: CM
authors.lastname: Hylden
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Johnson
authors.forename: Travis C
authors.initials: TC
authors.lastname: Burns
authors.forename: Jason M
authors.initials: JM
authors.lastname: Wilken
authors.forename: Johnny G
authors.initials: JG
authors.lastname: Owens
mesh_terms: D000328:Adult; D001182:Arthroscopy; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D006984:Hypertrophy; D007718:Knee Injuries / Q000534:rehabilitation* / Q000601:surgery; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D010865:Pilot Projects; D052097:Quadriceps Muscle / Q000098:blood supply*; D012039:Regional Blood Flow; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000000981:diagnostic imaging