title: Distal radius fracture metaphyseal comminution: a new radiographic parameter for quantifying, the metaphyseal collapse ratio (MCR).
abstract: BACKGROUND
  Metaphyseal comminution is widely considered as a key radiographic parameter that predicts fracture instability for distal radius fractures. However, no quantitative parameter is available to measure this degree of comminution. To quantify metaphyseal comminution objectively, the authors devised and validated the metaphyseal collapse ratio, a new radiographic index.
  
  
  METHODS
  Seventy-four cases of distal radius fracture in the elderly were included in this analysis. After closed reduction, a strictly lateral plain radiograph was obtained and digitally adjusted. The metaphyseal collapse ratio (MCR) was calculated expressing the maximal radiolucent extent as a percentage of the intercortical distance. Furthermore, correlations between MCR and age, gender, DXA scores, and other radiographic parameters, namely, radial shortening, volar tilt, radial inclination, and the presence of an associated ulnar fracture were investigated.
  
  
  RESULTS
  Mean metaphyseal collapse ratio in the cohort was calculated to be 51.7% by one observer and 53.7% by a second, showing good interobserver and mean intraobserver reliability (0.812, P<0.001 and 0.826, P<0.001, respectively). MCR was found to be significantly correlated with conventionally accepted radiographic parameters of fracture instability, that is, radial shortening (P<0.001), volar tilt (P<0.001), and radial inclination (P=0.002), but not with age, gender, DXA scores, and the presence of a combined ulnar fracture.
  
  
  CONCLUSIONS
  Metaphyseal collapse ratio, a novel radiographic parameter, was found to provide a reliable measure of metaphyseal comminution, and to be significantly correlated with other radiographic parameters that predict distal radius fracture instability.
  
  
  METHODS
  Level III, diagnostic.
authors.affiliation: Department of Orthopedic Surgery, Seoul National University Boramae Medical Center, Seoul, South Korea. Electronic address: hyskong@snu.ac.kr.
authors.forename: S H
authors.initials: SH
authors.lastname: Rhee
authors.forename: J
authors.initials: J
authors.lastname: Kim
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000379:methods; D017102:Fracture Healing / Q000502:physiology; D018460:Fractures, Comminuted / Q000000981:diagnostic imaging* / Q000601:surgery; D015577:Geriatric Assessment; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D015588:Observer Variation; D010147:Pain Measurement; D011182:Postoperative Care / Q000379:methods; D011859:Radiography; D011885:Radius Fractures / Q000000981:diagnostic imaging* / Q000534:rehabilitation / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D016896:Treatment Outcome; D014954:Wrist Injuries / Q000000981:diagnostic imaging* / Q000601:surgery
keywords: Distal radius fracture; Metaphyseal comminution; Radiographic parameter