title: Computed tomographic documentation of a comminuted fourth carpal bone fracture associated with carpal instability treated by partial carpal arthrodesis in an Arabian filly.
abstract: OBJECTIVE
  To report treatment of a unilateral comminuted fourth carpal bone (C4) fracture associated with carpal instability by partial carpal arthrodesis (PCA) of the middle carpal joint (MCJ) and carpometacarpal joint (CMCJ).
  
  
  METHODS
  Case Report.
  
  
  METHODS
  An 8-month-old Arabian filly.
  
  
  METHODS
  A C4 slab fracture was diagnosed radiographically; however, fracture comminution was conclusively diagnosed after computed tomographic (CT) imaging. PCA of the MCJ and CMCJ was performed with 2 narrow dynamic compression plates.
  
  
  RESULTS
  PCA provided appropriate carpal stability and correct limb alignment immediately after surgery. Complete bony fusion with substantial carpal flexion and no lameness at walk or light trot was observed 8 months after surgery.
  
  
  CONCLUSIONS
  Carpal CT was successfully used to define fracture configuration after standard radiographic examination failed to delineate comminution. PCA was selected because of joint instability and lateral carpal collapse of MCJ and CMCJ and can be successfully used to treat comminuted C4 slab fractures associated with carpal instability. Moderate MCJ osteoarthritis without radiocarpal joint involvement allows pain-free, substantial carpal flexion and thus, return to low-level pleasure riding may be possible.
  
  
  CONCLUSIONS
  CT imaging may more adequately characterize traumatic carpal bone injury, particularly, when carpal bone fracture configuration cannot be determined on standard radiographs. Early PCA of the MCJ and CMCJ is an useful alternative to treat comminuted C4 slab fractures that cannot be reconstructed.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA. Waselau.1@osu.edu
authors.forename: Martin
authors.initials: M
authors.lastname: Waselau
authors.forename: Alicia L
authors.initials: AL
authors.lastname: Bertone
authors.forename: Eric M
authors.initials: EM
authors.lastname: Green
mesh_terms: D000818:Animals; D001174:Arthrodesis / Q000379:methods / Q000662:veterinary*; D002348:Carpal Bones / Q000293:injuries / Q000601:surgery; D002350:Carpus, Animal / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery*; D005260:Female; D005593:Fracture Fixation, Internal / Q000379:methods / Q000662:veterinary; D018460:Fractures, Comminuted / Q000000981:diagnostic imaging / Q000601:surgery / Q000662:veterinary*; D006736:Horses / Q000293:injuries / Q000601:surgery; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000601:surgery / Q000662:veterinary; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000662:veterinary; D016896:Treatment Outcome