Ultrasonographic Ventral Hip Joint Approach and Relationship with Joint Laxity in Estrela Mountain Dogs

Hip dysplasia (HD) is a prevalent disease in medium to large-breed dogs, characterized by joint laxity and degenerative joint changes. Early diagnosis of HD poses significant challenges, as radiographic imaging often identifies the disease only in advanced stages. Conversely, ultrasonography, a non-invasive and cost-effective imaging modality, offers the potential for earlier detection by evaluating the surrounding soft tissues and synovial changes. This study aimed to assess the relationship between the ventral hip ultrasonographic findings, and hip joint laxity evaluated through stress radiographs on 22 young Estrela Mountain dogs (n=44 hips) aged 4 to 8 months. Key ultrasound measurements included synovial fluid in the cranial femoral neck recess (CFNR) and capsular-synovial fold thickness (CFT). Radiographic laxity was estimated by measuring the distraction index (DI). The mean ± standard deviation of the CFNR area, CFT, and DI was 45.58±25.40 mm², 3.21±0.90 mm, and 0.40±0.10, respectively. The Pearson correlation coefficient was statistically significant between all these variables (P<0.05). The ventral ultrasonographic approach to hip joint revealed potential, considering the early diagnosis of HD in dogs, by showing relationships between changes in periarticular soft tissues and joint laxity. Further studies are needed to associate ultrasonographic findings with radiographic signs of HD and related clinical signs in dogs.