Ultrasound is an accurate method compared to radiography for diagnosing the presence of acute hip luxation in cadaver dogs and can identify the direction of luxation with variable reliability

Abstract

Acute hip luxation is a common musculoskeletal injury in dogs, with radiographs being the preferred imaging modality for confirming the diagnosis. In large animal and human medicine, ultrasound is often utilized for this purpose. The objectives of this three‐part study were to utilize a canine cadaver model to establish ultrasonographic features of hip luxation and evaluate the accuracy and reliability for diagnosing hip luxation with ultrasound. For the first prospective, exploratory study, a cadaver model was developed that allowed manual luxation and subsequent ultrasonography of the hip joint while in four directions of luxation. For the second prospective, anatomic study, a description of the ultrasonographic features for each direction of luxation was created. For the third prospective diagnostic accuracy, observer agreement study, 16 residency‐trained and intern veterinarians without prior experience in this technique performed randomized, repeated ultrasound exams on cadaver hips assigned as normal or luxated (equally distributed between the 4 directions). A total of 1140 hip ultrasounds were performed with good accuracy (median, 90.8%; range, 61.4–100%), sensitivity (89.5%), and specificity (80.0%) for diagnosing the presence of hip luxation. Accuracy for identifying the correct quadrant of luxation was significantly lower (mean, 58.6%; range, 24.6–90.8%; P < 0.001). Intraobserver accuracy agreement varied widely from none to almost perfect agreement, and interobserver agreement ranged from slight to moderate agreement. The results of this study supported the use of ultrasound for diagnosing the presence of hip luxation but did not support replacing radiographs for diagnosing the direction of luxation.