Influence of Anaesthesia on Grading of Canine Hip Dysplasia

This study aimed to evaluate the effect of anesthesia on grading of canine hip dysplasia. For this purpose, 20 middle-sized healthy dogs from different breeds were used. Radiographs were taken using 4 different imaging methods, including the hip-extended, subluxation, distraction, and compression. This procedure was repeated 4 times for each dog, while the dogs were unanesthetized and anesthetized with 3 different anesthetic protocols at 15-day intervals (propofol [5 mg/kg, IV]; diazepam [0.5 mg/kg, IV] / ketamine [20 mg/kg, IV]; medetomidine [0.05 μg/kg, IM] / ketamine [20 mg/kg, IM]). The radiographs were taken and evaluated by the same investigator to prevent interobserver variation. Because of the radiographic positioning difficulty, unanesthetized radiographic imaging revealed higher repetition number than the anesthetized; therefore, radiation safety decreased. The administration of diazepam/ketamine and medetomidine/ketamine was sufficient in terms of both muscle relaxation and duration of the anesthesia; however, some dogs under propofol anesthesia were required maintenance doses to complete radiographic imaging procedure. Unanesthetized radiographic images of the dogs had significantly lower (P < .001) hip score, distraction index (DI), subluxation index (SI), and higher compression index (CI) (P< .001), when compared with anesthetized radiographic images. When compared the anesthetic protocols, propofol revealed lower (P< 0.001) hip score, DI, SI, and higher (P < .001) CI than medetomidine/ketamine. Medetomidine/ketamine is the most appropriate anesthetic protocol for detailed radiographic evaluation of CHD considering both muscle relaxation and duration of action.