Histological Analysis and Evaluation of the Efficacy of Computed Tomography on Diagnosis of Legg–Calvé–Perthes Disease in Toy Poodles: A Retrospective Study

Introduction: Legg–Calvé–Perthes Disease (LCPD) affects young small breed dogs. We hypothesized that computed tomography (CT) is superior to radiography in detecting LCPD. The goal of this study is to describe the femoral head of Toy Poodles affected by LCPD on histology, radiography, and CT. First, we will detail histological changes of LCPD utilizing bright and polarized light microscopy. Second, we will evaluate efficacy of radiography and CT to diagnose LCPD.

Materials and Methods: Fourteen Toy Poodles diagnosed with LCPD from two referral practices were included. Age, body weight, sex, and duration of clinical signs were collected. All patients underwent femoral head and neck ostectomies. Femoral heads were collected and processed. Histology was graded based on severity, chronicity, and cartilage pathology. CTs and radiographs were graded on severity of lesions. McNemar’s test was used to correlate histology to CT and radiographs.

Results: McNemar’s test revealed that CT was stronger than radiographs when compared with histology grade (p < 0.10).

Discussion/Conclusion: We revealed that CT had a stronger correlation to histological grade when compared with radiographs of the same dog. Histologically, LCPD lesions appeared distinct under both bright light and polarized microscopy. The strength of the study is that all enrolled cases are Toy Poodles, therefore breed differences did not contribute to the results; however, it is limited in the number of cases enrolled. Future comparison between Toy Poodles and other breeds will be compiled to see if breed affects CT as a diagnostic for LCPD.

Acknowledgment: Funding for this project was provided by Fujiirdera Animal Hospital and NORTHLAB.