title: Below-Knee Amputation Failure and Poor Functional Outcomes Are Higher Than Predicted in Contemporary Practice.
abstract: OBJECTIVE
  The perceived functional benefit of below-knee amputation (BKA) must be carefully weighed against the need for potential reinterventions. This study sought to examine the contemporary clinical and functional outcomes of patients undergoing BKA in the endovascular era.
  
  
  METHODS
  All patients who underwent BKA from January 2008 to December 2014 at a single tertiary medical center were retrospectively reviewed. Demographics, comorbidities, ambulation status, and transcutaneous oximetry (TcPO2) values were recorded. Study end points included freedom from conversion to above-knee amputation (AKA), freedom from conversion to AKA or death, BKA healing, and ambulation. Statistical modeling was performed to determine associations with BKA failure.
  
  
  RESULTS
  Over the study interval, 130 limbs underwent BKA in 120 patients. Transcutaneous oximetry studies were obtained in 65% (n = 85). Thirty-eight percent (n = 46) of all BKA patients went on to heal and ambulate. Twenty-five percent (n = 33) required reintervention, 24 with conversion to AKA, and 9 with BKA revision. One-year freedom from conversion to AKA was 76% and was decreased among those with lower TcPO2 levels (60% TcPO2 <40 vs 81% TcPO2 ≥40; P = .04). One-year composite freedom from conversion to AKA/death was 60% and was decreased among those with lower TcPO2 readings (39% TcPO2 <40 vs 69% TcPO2 ≥40; P = .01).
  
  
  CONCLUSIONS
  Despite a perceived functional bias toward knee salvage at the time of major amputation, most patients failed to postoperatively ambulate. Those with decreased TcPO2 levels (<40 mm Hg) have a 2-fold higher risk of AKA conversion or death, while nearly one-fourth of all BKA patients will succumb to the same fate irrespective of TcPO2. This suggests that many BKA patients in the endovascular era fail to derive the perceived benefit of knee salvage at the time of their index amputation. These findings highlight the need for careful patient selection and for a shared decision-making model in this frail population.
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Jesse A
authors.initials: JA
authors.lastname: Columbo
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Brian W
authors.initials: BW
authors.lastname: Nolan
authors.affiliation: 2 Department of General Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Ryland S
authors.initials: RS
authors.lastname: Stucke
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Rzucidlo
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Walker
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Powell
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: Bjoern D
authors.initials: BD
authors.lastname: Suckow
authors.affiliation: 1 Section of Vascular Surgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Stone
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical / Q000009:adverse effects* / Q000401:mortality; D001785:Blood Gas Monitoring, Transcutaneous; D004185:Disability Evaluation; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D009513:New Hampshire; D058729:Peripheral Arterial Disease / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D020127:Recovery of Function; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D062606:Tertiary Care Centers; D013997:Time Factors; D017211:Treatment Failure
keywords: amputation; amputation revision; critical limb ischemia