title: Reliability of a complication classification system for orthopaedic surgery.
abstract: BACKGROUND
  Quality of health care and safety have been emphasized by various professional and governmental groups. However, no standardized method exists for grading and reporting complications in orthopaedic surgery. Conclusions regarding outcomes are incomplete without a standardized, objective complication grading scheme applied concurrently. The general surgery literature has the Clavien-Dindo classification that meets the above criteria.
  
  
  OBJECTIVE
  We asked whether a previously reported classification would show high intraobserver and interobserver reliabilities when modified for orthopaedic surgery specifically looking at hip preservation surgery. We therefore determined the interreader and intrareader reliabilities of the adapted classification scheme as applied to hip preservation surgery.
  
  
  METHODS
  We adapted the validated Clavien-Dindo complication classification system and tested its reliability for orthopaedic surgery, specifically hip preservation surgery. There are five grades based on the treatment required to manage the complication and the potential for long-term morbidity. Forty-four complication scenarios were created from a prospective multicenter database of hip preservation procedures and from the literature. Ten readers who perform hip surgery at eight centers in three countries graded the scenarios at two different times. Fleiss' and Cohen's κ statistics were performed for interobserver and intraobserver reliabilities, respectively.
  
  
  RESULTS
  The overall Fleiss' κ value for interobserver reliability was 0.887 (95% CI, 0.855-0.891). The weighted κ was 0.925 (95% CI, 0.894-0.956) for Grade I, 0.838 (95% CI, 0.807-0.869) for Grade II, 0.87 (95% CI, 0.835-0.866) for Grade III, and 0.898 (95% CI, 0.866-0.929) for Grade IV. The Cohen's κ value for intraobserver reliability was 0.891 (95% CI, 0.857-0.925).
  
  
  CONCLUSIONS
  The adapted classification system shows high interobserver and intraobserver reliabilities for grading of complications when applied to orthopaedic surgery looking at complications of hip preservation surgery. This grading scheme may facilitate standardization of complication reporting and make outcome studies more comparable.
authors.affiliation: Hospital for Special Surgery, New York, NY 10021, USA. sinke@hss.edu
authors.forename: Ernest L
authors.initials: EL
authors.lastname: Sink
authors.forename: Michael
authors.initials: M
authors.lastname: Leunig
authors.forename: Ira
authors.initials: I
authors.lastname: Zaltz
authors.forename: Jennifer Claire
authors.initials: JC
authors.lastname: Gilbert
authors.forename: John
authors.initials: J
authors.lastname: Clohisy
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D019637:Orthopedic Procedures / Q000009:adverse effects*; D009985:Orthopedics / Q000592:standards*; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000592:standards*; D011183:Postoperative Complications / Q000145:classification* / Q000175:diagnosis; D015203:Reproducibility of Results