title: Orthogonal view analysis for evaluating the femoral component position of total hip implants in dogs using postoperative radiographs.
abstract: OBJECTIVE
  To show the ability to obtain repeatable, accurate, quantitative data to assess the position of the femoral component of canine total hip implants using postoperative radiographs.
  
  
  METHODS
  Cadaveric study and clinical trial.
  
  
  METHODS
  Five cadaveric canine femurs and 4 patients.
  
  
  METHODS
  Femoral implants were placed into 5 cadaveric canine femurs in predetermined locations. Orthogonal radiographs were taken of each femur at 10 degrees intervals as they were moved through a natural range of hip motion. An assessment of implant position was made with each set of radiographs and analyzed to observe significant inconsistencies in the values obtained when the femur was repositioned. Three investigators positioned and radiographed the hips of 4 client-owned dogs that had total hip arthroplasty (THA). Each investigator obtained a set of orthogonal radiographic views from which implant position was measured. The measurements obtained from each investigator's set of radiographs were statistically analyzed to evaluate for interobserver differences.
  
  
  RESULTS
  The methods described indicate that consistent data regarding femoral implant placement can be obtained from postoperative radiographs of THA patients. Under most circumstances, change in position of the femur did not significantly affect femoral implant measurements. There were no significant differences noted among values obtained by different investigators.
  
  
  CONCLUSIONS
  Measurements based on the femoral and implant axes obtained from orthogonal radiographic views of the femur provide a means for obtaining accurate and consistent quantitative data regarding femoral implant position using postoperative radiographs of canine THA patients.
  
  
  CONCLUSIONS
  Acquisition of quantitative information about femoral implant position using postoperative radiographs will facilitate development of a readily available data source. This information, attainable in a clinical setting, may help identify elements of implant position that are important in determining the clinical outcome of THA in dogs.
authors.affiliation: University of Wisconsin-Madison School of Veterinary Medicine, Comparative Orthopaedics Research Laboratory, 53706, USA.
authors.forename: Carl T
authors.initials: CT
authors.lastname: Jehn
authors.forename: Mary Sarah
authors.initials: MS
authors.lastname: Bergh
authors.forename: Paul A
authors.initials: PA
authors.lastname: Manley
mesh_terms: D000818:Animals; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000662:veterinary*; D002102:Cadaver; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D006622:Hip Prosthesis / Q000662:veterinary*; D007091:Image Processing, Computer-Assisted / Q000592:standards*; D015207:Osteoarthritis, Hip / Q000601:surgery / Q000662:veterinary*; D011859:Radiography; D012680:Sensitivity and Specificity