Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Four The Appendicular Skeleton 563
A
B
Fig. 4-114 A 2-year-old female Chesapeake Bay Retriever was brought in for routine hip evaluation.
A, There is subluxation of the right coxofemoral joint with no remodeling changes present. B,
Follow-up radiographs were obtained 2 years later. At this time both femoral heads appear deeply
seated within their respective acetabula. Joint surfaces are smooth. There is no evidence of degenerative
joint disease. The pelvic conformation appears normal at this age. Although the animal
appeared to have dysplastic hips at 2 years of age, the follow-up radiographs indicate that the pelvis
is normal. This is an unusual occurrence; however, it emphasizes the need for follow-up radiographs
in animals in which the radiographic evidence of hip dysplasia is minimal. Diagnosis: Normal
pelvis.
24 months of age should be considered provisional. A repeat study at 2 1 2 or 3 years of age
may be required in dogs with borderline pelvic conformation.
Another study has shown that preliminary readings (i.e., before 24 months of age) are
generally reliable. The correlations with the final diagnoses were best at the extremes of the
range (excellent hip joint conformation had 100% correlation, moderate hip dysplasia had
94.7% correlation). Correlations were weaker in the less definitive ends of the range of
diagnoses (76.9% for fair hip joint conformation and 84.4% with mild hip dysplasia). 493
The OFA has defined standards of hip joint conformation ranging from excellent hip
joint conformation (superior hip joint conformation as compared with other individuals
of the same breed and age) to severe hip dysplasia (radiographic evidence of marked dys-