Canine Hip Dysplasia Study Guide

Overview and Clinical Importance

Canine hip dysplasia (CHD) is the most common developmental orthopedic disease in dogs, characterized by coxofemoral joint laxity, progressive degeneration, and secondary osteoarthritis (OA). First described in the 1930s, CHD continues to affect millions of dogs worldwide, with prevalence ranging from 1% to over 70% depending on breed. Understanding CHD is essential for the NAVLE as questions frequently test pathophysiology, diagnosis, breed predisposition, radiographic interpretation, and treatment selection.

CHD is a polygenic, multifactorial disease where both genetic predisposition and environmental factors (nutrition, exercise, growth rate) influence expression. Dogs are born with normal hips, but joint laxity develops within the first few weeks of life, leading to abnormal joint mechanics, cartilage damage, and eventual OA.

Etiology and Pathophysiology

Genetic Factors

CHD is a polygenic trait with complex inheritance patterns. The heritability ranges from 0.2 to 0.6 depending on breed. Key genetic factors include abnormal collagen composition in the joint capsule leading to reduced stiffness, delayed endochondral ossification of hip structures, and variations in genes associated with cartilage and bone development.