title: Synovial fluid cavitation during distraction radiography of the coxofemoral joint in dogs.
abstract: OBJECTIVE
  To determine risk factors for, and prevalence and short- and long-term effects of synovial fluid cavitation during distraction radiography.
  
  
  METHODS
  Multicenter prevalence survey.
  
  
  METHODS
  6,649 purebred dogs comprising 129 breeds.
  
  
  METHODS
  Radiographs from the PennHIP (University of Pennsylvania Hip Improvement Program) Laboratory were subjectively evaluated for evidence of cavitation. Multiple logistic regression was used to determine whether sex, breed, age, weight, distraction index (DI), or examining veterinarian was associated with cavitation. Short-term effects of cavitation were assessed by comparing DI for the hip with cavitation with DI for the contralateral hip in dogs with unilateral cavitation. Long-term effects of cavitation were assessed by comparing DI before and after cavitation was detected.
  
  
  RESULTS
  Cavitation was detected in 279 (4.2%) of the radiographs analyzed. Male dogs, Golden Retrievers, and heavier dogs were at a decreased risk for cavitation. Irish Wolfhounds, Irish Setters, Rhodesian Ridgebacks, and Weimaraners had an increased risk for cavitation. Age and DI were not risk factors for cavitation. Mean DI was 0.08 greater in hips with cavitation than in paired hips without cavitation. Significant differences were not detected between DI before and after cavitation, but only 7 dogs were included in this analysis.
  
  
  CONCLUSIONS
  Cavitation is rare during distraction radiography and can increase measured DI. Radiographs should be routinely examined to ensure accurate reporting of DI.
authors.affiliation: Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA.
authors.forename: E
authors.initials: E
authors.lastname: LaFond
authors.forename: G K
authors.initials: GK
authors.lastname: Smith
authors.forename: T P
authors.initials: TP
authors.lastname: Gregor
authors.forename: P J
authors.initials: PJ
authors.lastname: McKelvie
authors.forename: F S
authors.initials: FS
authors.lastname: Shofer
mesh_terms: D000818:Animals; D001175:Arthrography / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D001947:Breeding; D004283:Dog Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D004285:Dogs; D005260:Female; D006619:Hip Dysplasia, Canine / Q000000981:diagnostic imaging; D006621:Hip Joint / Q000000981:diagnostic imaging*; D007592:Joint Diseases / Q000453:epidemiology / Q000209:etiology / Q000662:veterinary*; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000662:veterinary; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D013582:Synovial Fluid