title: New classification of lunate fossa fractures of the distal radius.
abstract: BACKGROUND
  A die-punch fracture is a depression fracture of the lunate fossa of the distal radius. We propose a morphological classification of die-punch fractures that includes five types: center depression fractures, vertical depression fractures, volar depression fractures, dorsal depression fractures, and double die-punch fractures.
  
  
  METHODS
  The radiographs of 112 die-punch fractures treated between January 2005 and January 2015 were retrospectively reviewed. The clinical images were examined independently for two rounds by six orthopedists with different clinical experiences: two residents, two attending physicians, and two consultants. A category-specific kappa score and a kappa score for more than two observers were analyzed. We used Cohen's kappa to test intraobserver variation.
  
  
  RESULTS
  The kappa score for interobserver reliability was 0.69 for the first round and 0.70 for the second round. The intraclass correlations were 0.65 and 0.63, respectively. Intraobserver reproducibility using Cohen's kappa test was satisfactory. All of the results indicated a kappa value >0.4, suggesting good agreement within, as well as between, observers.
  
  
  CONCLUSIONS
  The outcome was assessed using kappa statistics, which showed good interobserver reliability and intraobserver reproducibility.
authors.affiliation: Department of Orthopaedics, Chinese People's Liberation Army General Hospital (301 Hospital), Beijing, 100038, China.|Department of Orthopaedics, The Affiliated Hospital of Inner Mongolia Medical University, Hohhot, 010000, Inner Mongolia, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Chinese People's Liberation Army General Hospital (301 Hospital), Beijing, 100038, China.
authors.forename: Xin Ran
authors.initials: XR
authors.lastname: Ji
authors.affiliation: Department of Orthopaedics, Chinese People's Liberation Army General Hospital (301 Hospital), Beijing, 100038, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Orthopaedics, Chinese People's Liberation Army General Hospital (301 Hospital), Beijing, 100038, China.
authors.forename: Jian Tao
authors.initials: JT
authors.lastname: Li
authors.affiliation: Department of Orthopaedics, Chinese People's Liberation Army General Hospital (301 Hospital), Beijing, 100038, China. zhanglihai74@qq.com.|General Hospital of PLA, Haidian District 28, Beijing, 100038, China. zhanglihai74@qq.com.
authors.forename: Li Hai
authors.initials: LH
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Chinese People's Liberation Army General Hospital (301 Hospital), Beijing, 100038, China. pftang301@163.com.|General Hospital of PLA, Haidian District 28, Beijing, 100038, China. pftang301@163.com.
authors.forename: Pei Fu
authors.initials: PF
authors.lastname: Tang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011885:Radius Fractures / Q000145:classification* / Q000000981:diagnostic imaging; D013223:Statistics as Topic; D055815:Young Adult
keywords: Classification; Die-punch fracture; Radius