title: Continuous femoral nerve block using 0.125% bupivacaine does not prevent early ambulation after total knee arthroplasty.
abstract: BACKGROUND
  Continuous femoral nerve block has been shown to decrease opioid use, improve postoperative pain scores, and decrease length of stay. However, several studies have raised the concern that continuous femoral nerve block may delay patient ambulation and increase the risk of falls during the postoperative period.
  
  
  OBJECTIVE
  This study sought to determine whether continuous femoral nerve block with a single-shot sciatic block prevented early ambulation after total knee arthroplasty (TKA) and whether the technique was associated with adverse effects.
  
  
  METHODS
  Between January 2011 and January 2013, 77 consecutive patients undergoing primary TKAs at an orthopaedic specialty hospital received a continuous femoral nerve block for perioperative analgesia. The femoral block was placed preoperatively with an initial bolus and 76 (99%) patients received a single-shot sciatic nerve block performed at the same time. Fifty-eight percent (n = 45) received an initial bolus of 0.125% bupivacaine and 42% (n = 32) received 0.25% bupivacaine. All 77 patients received 0.125% bupivacaine infusion postoperatively with the continuous femoral nerve block. All patients were provided a knee immobilizer that was worn while they were out of bed and was used until 24 hours after removal of the block. All patients also used a front-wheeled walker to assist with ambulation. All 77 patients had complete records for assessing the end points of interest in this retrospective case series, including distance ambulated each day and whether in-hospital complications could be attributed to the patients' nerve blocks.
  
  
  RESULTS
  Thirty-five patients (45%) ambulated for a mean distance of 19 ± 22 feet on the day of surgery. On postoperative Days 1 and 2, all 77 patients successfully ambulated a mean of 160 ± 112 and 205 ± 123 feet, respectively. Forty-eight patients (62%) had documentation of ascending/descending stairs during their hospital stay. No patient fell during the postoperative period, required return to the operating room, or readmission within 90 days of surgery. One patient experienced a transient foot drop related to the sciatic nerve block, which resolved by postoperative Day 1.
  
  
  CONCLUSIONS
  Continuous femoral nerve block with dilute bupivacaine (0.125%) can be successfully used after TKA without preventing early ambulation. By taking active steps to prevent in-hospital falls, including the use of a knee immobilizer for ambulation while the block is in effect, patients can benefit from the analgesia provided by the block and still ambulate early after TKA.
  
  
  METHODS
  Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, University of Utah School of Medicine, 590 Wakara Way, Salt Lake City, UT, 84108, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Beebe
authors.forename: Rachel
authors.initials: R
authors.lastname: Allen
authors.forename: Mike B
authors.initials: MB
authors.lastname: Anderson
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Swenson
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Peters
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D002045:Bupivacaine / Q000008:administration & dosage* / Q000009:adverse effects; D051341:Dependent Ambulation; D004434:Early Ambulation; D005260:Female; D005267:Femoral Nerve; D006801:Humans; D007103:Immobilization; D007263:Infusions, Parenteral; D007267:Injections; D007719:Knee Joint / Q000294:innervation / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000009:adverse effects / Q000379:methods*; D010149:Postoperative Pain / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D020127:Recovery of Function; D012189:Retrospective Studies; D012584:Sciatic Nerve; D013997:Time Factors; D016896:Treatment Outcome; D014853:Walkers; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine