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. The 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 (<i>n</i> = 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 median (quartile 25-75%) of the CFNR area, CFT, and DI were 44.00 (27.00-52.25) mm², 3.10 (2.68-3.55) mm, and 0.38 (0.34-0.40), respectively. The Spearman correlation coefficient was statistically significant between all of these variables (<i>p</i> < 0.05). The ventral ultrasonographic approach to the 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.