Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Four The Appendicular Skeleton 557
A
B
Fig. 4-106 A 3-year-old male mixed breed dog was hit by a car and became lame immediately in the
left hind limb. A, There is a luxation of the proximal intertarsal joint (black arrows) and moderate
soft-tissue swelling in the area. B, The dorsoplantar view reveals the soft-tissue swelling but the luxation
is obscured. Diagnosis: Partial luxation of the proximal intertarsal joint.
Conformational or Developmental Hip Dysplasia. Hip dysplasia is a multifactorial, clinically
complex arthropathy with structural alterations of the coxofemoral joints. Although
dogs are afflicted most commonly, cats may also have hip dysplasia. 468-471 The anatomical
alterations of hip dysplasia include shallow acetabula, swelling or tearing of the round ligament,
joint subluxation, erosion of articular cartilage, and remodeling of the acetabulum
as well as the femoral head and neck surfaces. 472 One or both hips may be involved. 473-476
The causes of canine hip dysplasia are numerous and possibly interactive. 477-482 The manner
and degree in which these pathologies cause radiographic changes are not consistent.
Any or all of the radiographic changes of canine hip dysplasia, including shallow acetabula,
coxofemoral subluxation, remodeling of the acetabulum, femoral head, or femoral neck, or
periarticular osteophytosis, may be present (Figs. 4-110 to 4-114). The degree of radiographic
change does not necessarily correlate with the clinical signs.