Despite considerable research and the application of screening programs dur
ing the past three decades, the incidence of canine hip dysplasia (CHD) rem
ains disturbingly high. Mild CHD is underdiagnosed by subjective evaluation
of adult dogs, and moderate CHD is underdiagnosed by subjective assessment
of immature dogs. Coxofemoral subluxation measurement methods hold promise
for increasing the accuracy of CHD assessment, especially in 4-month-old d
ogs. Many radiologists have greater confidence in the PennHip method than i
n subjective hip assessment alone for dogs 6 months of age or younger. The
incidence of CHD is unlikely to be dramatically reduced until CHD registrie
s are open to the public and CHD examination is required for purebred dog r
egistration.