title: Bone mineral density loss after combat-related lower extremity amputation.
abstract: OBJECTIVE
  Determine the incidence, severity, and associated risk factors for the development of low bone mineral density (BMD) after combat-related lower extremity amputation.
  
  
  METHODS
  Retrospective case-control comparison.
  
  
  METHODS
  Tertiary care military treatment facility.
  
  
  METHODS
  One hundred fifty-six lower extremity amputees, representing 182 amputations (121 unilateral, 35 bilateral).
  
  
  METHODS
  All patients underwent dual energy x-ray absorptiometry scanning during the treatment period.
  
  
  METHODS
  The Z score was the main outcome measure. We identified all patients with low BMD (Z < -1.0) and conducted multivariate analysis to identify significant risk factors for low BMD development.
  
  
  RESULTS
  The observed rate of low BMD was 42%. The average Z score was -0.6 ± 1.1 among unilateral amputations and -1.2 ± 1.0 among bilateral amputations (P = 0.005). Risk factors for the development of low BMD were prolonged time to first ambulation [odds ratio (OR) = 1.39; 95% confidence interval (CI): 1.003-1.93; P = 0.048], prolonged time to dual energy x-ray absorptiometry (OR = 1.10; 95% CI: 1.02-1.18; P = 0.009), and more proximal amputation level (OR = 7.27; 95% CI: 3.21-16.49; P < 0.001). Among unilateral amputees, we detected a significant difference in the BMD of the intact and amputated limbs (-1.0; 95% CI: -1.1 to -0.8; P < 0.001).
  
  
  CONCLUSIONS
  Proximal amputation level and delayed ambulation demonstrated a significant relationship with low BMD after traumatic and trauma-related amputation. We conclude that transfemoral amputees are at greater risk of BMD loss and that disuse atrophy is a primary factor in the development of low BMD. Prevention should focus on early and aggressive weight bearing rehabilitation and assessing levels and appropriately supplementing calcium and vitamin D.
authors.affiliation: *Department of Orthopaedic, Walter Reed National Military Medical Center, Bethesda, MD; and †Department of Surgery, Uniformed Services University of Health Sciences, Bethesda, MD.
authors.forename: James H
authors.initials: JH
authors.lastname: Flint
authors.forename: Alana M
authors.initials: AM
authors.lastname: Wade
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Stocker
authors.forename: Paul F
authors.initials: PF
authors.lastname: Pasquina
authors.forename: Robin S
authors.initials: RS
authors.lastname: Howard
authors.forename: Benjamin K
authors.initials: BK
authors.lastname: Potter
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000671:Amputation, Surgical / Q000009:adverse effects*; D018488:Bone Demineralization, Pathologic / Q000209:etiology*; D015519:Bone Density; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007869:Leg Injuries / Q000000981:diagnostic imaging* / Q000601:surgery* / Q000628:therapy; D035002:Lower Extremity / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D008297:Male; D008889:Military Personnel / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D014857:Warfare; D055815:Young Adult