title: The Amsterdam wrist rules: the multicenter prospective derivation and external validation of a clinical decision rule for the use of radiography in acute wrist trauma.
abstract: BACKGROUND
  Although only 39 % of patients with wrist trauma have sustained a fracture, the majority of patients is routinely referred for radiography. The purpose of this study was to derive and externally validate a clinical decision rule that selects patients with acute wrist trauma in the Emergency Department (ED) for radiography.
  
  
  METHODS
  This multicenter prospective study consisted of three components: (1) derivation of a clinical prediction model for detecting wrist fractures in patients following wrist trauma; (2) external validation of this model; and (3) design of a clinical decision rule. The study was conducted in the EDs of five Dutch hospitals: one academic hospital (derivation cohort) and four regional hospitals (external validation cohort). We included all adult patients with acute wrist trauma. The main outcome was fracture of the wrist (distal radius, distal ulna or carpal bones) diagnosed on conventional X-rays.
  
  
  RESULTS
  A total of 882 patients were analyzed; 487 in the derivation cohort and 395 in the validation cohort. We derived a clinical prediction model with eight variables: age; sex, swelling of the wrist; swelling of the anatomical snuffbox, visible deformation; distal radius tender to palpation; pain on radial deviation and painful axial compression of the thumb. The Area Under the Curve at external validation of this model was 0.81 (95 % CI: 0.77-0.85). The sensitivity and specificity of the Amsterdam Wrist Rules (AWR) in the external validation cohort were 98 % (95 % CI: 95-99 %) and 21 % (95 % CI: 15 %-28). The negative predictive value was 90 % (95 % CI: 81-99 %).
  
  
  CONCLUSIONS
  The Amsterdam Wrist Rules is a clinical prediction rule with a high sensitivity and negative predictive value for fractures of the wrist. Although external validation showed low specificity and 100 % sensitivity could not be achieved, the Amsterdam Wrist Rules can provide physicians in the Emergency Department with a useful screening tool to select patients with acute wrist trauma for radiography. The upcoming implementation study will further reveal the impact of the Amsterdam Wrist Rules on the anticipated reduction of X-rays requested, missed fractures, Emergency Department waiting times and health care costs.
  
  
  BACKGROUND
  This study was registered in the Dutch Trial Registry, reference number NTR2544 on October 1(st), 2010.
authors.affiliation: Department of Surgery, Trauma Unit, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. m.m.walenkamp@amc.nl.
authors.forename: Monique M J
authors.initials: MM
authors.lastname: Walenkamp
authors.affiliation: Department of Surgery, Trauma Unit, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. a.bentohami@gmail.com.
authors.forename: Abdelali
authors.initials: A
authors.lastname: Bentohami
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. a.slaar@amc.nl.
authors.forename: Annelie
authors.initials: A
authors.lastname: Slaar
authors.affiliation: Department of Surgery, Trauma Unit, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. m.s.beerekamp@amc.nl.
authors.forename: M Suzan H
authors.initials: MS
authors.lastname: Beerekamp
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. m.maas@amc.nl.
authors.forename: Mario
authors.initials: M
authors.lastname: Maas
authors.affiliation: Emergency Department, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. carajager@gmail.com.
authors.forename: L Cara
authors.initials: LC
authors.lastname: Jager
authors.affiliation: Spaarne Hospital, Department of Surgery, P.O. Box 770, Hoofddorp, 2130 AT, The Netherlands. nsosef@spaarneziekenhuis.nl.
authors.forename: Nico L
authors.initials: NL
authors.lastname: Sosef
authors.affiliation: Tergooi Hospitals, Department of Surgery, P.O. Box 10016, Hilversum, 1201 DA, The Netherlands. rvanvelde@tergooi.nl.
authors.forename: Romuald
authors.initials: R
authors.lastname: van Velde
authors.affiliation: Sint Lucas Andreas Hospital, Department of Surgery, P.O. box 9243, Amsterdam, 1006 AE, The Netherlands. ultee@knmg.nl.
authors.forename: Jan M
authors.initials: JM
authors.lastname: Ultee
authors.affiliation: Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Rotterdam, 3000 CA, The Netherlands. e.steyerberg@erasmusmc.nl.
authors.forename: Ewout W
authors.initials: EW
authors.lastname: Steyerberg
authors.affiliation: Department of Surgery, Trauma Unit, Academic Medical Center, University of Amsterdam, P.O. Box 22660, Amsterdam, 1100 DD, The Netherlands. j.c.goslings@amc.nl.
authors.forename: J Carel
authors.initials: JC
authors.lastname: Goslings
authors.affiliation: Maasstad Hospital, Department of Surgery, P.O. Box 9100, Rotterdam, 3007 AC, The Netherlands. schepn@maasstadziekenhuis.nl.
authors.forename: Niels W L
authors.initials: NW
authors.lastname: Schep
mesh_terms: D000328:Adult; D000368:Aged; D000066491:Clinical Decision-Making; D015331:Cohort Studies; D004636:Emergency Service, Hospital / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011446:Prospective Studies; D011859:Radiography / Q000592:standards / Q000706:statistics & numerical data; D014954:Wrist Injuries / Q000000981:diagnostic imaging* / Q000453:epidemiology