title: Radiographic risk factors for contralateral rupture in dogs with unilateral cranial cruciate ligament rupture.
abstract: BACKGROUND
  Complete cranial cruciate ligament rupture (CR) is a common cause of pelvic limb lameness in dogs. Dogs with unilateral CR often develop contralateral CR over time. Although radiographic signs of contralateral stifle joint osteoarthritis (OA) influence risk of subsequent contralateral CR, this risk has not been studied in detail.
  
  
  RESULTS
  We conducted a retrospective longitudinal cohort study of client-owned dogs with unilateral CR to determine how severity of radiographic stifle synovial effusion and osteophytosis influence risk of contralateral CR over time. Detailed survival analysis was performed for a cohort of 85 dogs after case filtering of an initial sample population of 513 dogs. This population was stratified based on radiographic severity of synovial effusion (graded on a scale of 0, 1, and 2) and severity of osteophytosis (graded on a scale of 0, 1, 2, and 3) of both index and contralateral stifle joints using a reproducible scoring method. Severity of osteophytosis in the index and contralateral stifles was significantly correlated. Rupture of the contralateral cranial cruciate ligament was significantly influenced by radiographic OA in both the index and contralateral stifles at diagnosis. Odds ratio for development of contralateral CR in dogs with severe contralateral radiographic stifle effusion was 13.4 at one year after diagnosis and 11.4 at two years. Odds ratio for development of contralateral CR in dogs with severe contralateral osteophytosis was 9.9 at one year after diagnosis. These odds ratios were associated with decreased time to contralateral CR. Breed, age, body weight, gender, and tibial plateau angle did not significantly influence time to contralateral CR.
  
  
  CONCLUSIONS
  Subsequent contralateral CR is significantly influenced by severity of radiographic stifle effusion and osteophytosis in the contralateral stifle, suggesting that synovitis and arthritic joint degeneration are significant factors in the disease mechanism underlying the arthropathy.
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Connie
authors.initials: C
authors.lastname: Chuang
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Megan A
authors.initials: MA
authors.lastname: Ramaker
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Sirjaut
authors.initials: S
authors.lastname: Kaur
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Csomos
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Kroner
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Bleedorn
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Schaefer
authors.affiliation: Comparative Orthopaedic Research Laboratory, and the Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Peter
authors.initials: P
authors.lastname: Muir
mesh_terms: D000818:Animals; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging*; D000070598:Anterior Cruciate Ligament Injuries; D004285:Dogs / Q000293:injuries*; D005260:Female; D008297:Male; D011859:Radiography; D012307:Risk Factors; D012421:Rupture / Q000000981:diagnostic imaging / Q000662:veterinary; D016019:Survival Analysis