title: Biomechanical studies: science (f)or common sense?
abstract: BACKGROUND
  It is our impression that many biomechanical studies invest substantial resources studying the obvious: that more and larger metal is stronger. The purpose of this study is to evaluate if a subset of biomechanical studies comparing fixation constructs just document common sense.
  
  
  METHODS
  Using a web-based survey, 274 orthopaedic surgeons and 81 medical students predicted the results of 11 biomechanical studies comparing fracture fixation constructs (selected based on the authors' sense that the answer was obvious prior to performing the study). Sensitivity, specificity, and accuracy were calculated according to standard formulas. The agreement among the observers was calculated by using a multirater kappa, described by Siegel and Castellan.
  
  
  RESULTS
  The accuracy of predicting outcomes was 80% or greater for 10 of 11 studies. Accuracy was not influenced by level of experience (i.e., time in practice and medical students vs. surgeons). There were substantial differences in accuracy between observers from different regions. The overall categorical rating of inter-observer reliability according to Landis and Koch was moderate (κ=0.55; standard error (SE)=0.01).
  
  
  CONCLUSIONS
  The results of a subset of biomechanical studies comparing fracture fixation constructs can be predicted prior to doing the study. As these studies are time and resource intensive, one criterion for proceeding with a biomechanical study should be that the answer is not simply a matter of common sense.
authors.affiliation: Orthopaedic Hand and Upper Extremity Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Jos J
authors.initials: JJ
authors.lastname: Mellema
authors.affiliation: University of Amsterdam Orthopaedic Residency Program (PGY 4), Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Job N
authors.initials: JN
authors.lastname: Doornberg
authors.affiliation: University of Amsterdam Orthopaedic Residency Program (PGY 4), Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Thierry G
authors.initials: TG
authors.lastname: Guitton
authors.affiliation: Orthopaedic Hand and Upper Extremity Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: dring@partners.org.
authors.forename: David
authors.initials: D
authors.lastname: Ring
mesh_terms: D001696:Biomechanical Phenomena; D005592:Fracture Fixation / Q000193:education / Q000379:methods; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D007600:Judgment; D015588:Observer Variation; D011361:Professional Competence / Q000592:standards; D011859:Radiography; D015203:Reproducibility of Results; D058028:Research Report / Q000592:standards; D013337:Students, Medical / Q000706:statistics & numerical data; D066231:Surgeons / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
keywords: Biomechanical; Fixation; Fracture; Orthopaedic