Hypothesis 1 – Developmental Disease causing lameness

9 month old immature large-breed dog
In this case the bones of the pelvic limb and hip have not fully developed and are susceptible to injury
History and physical exam localized to the coxofemoral joint(s). Possible joint laxity can lead to joint 
subluxation. The weight-bearing surface of the femoral head and acetabulum is reduced, causing erosion 
and damage to the joint cartilage. The cartilage may thicken in attempt to stabilize the joint, and the 
cartilage surfaces become inflamed and roughened. The dog is more painful in the AM because of stiffness 
in the joint, and after exercise the roughened cartilage surfaces rub together causing joint damage, 
inflammation, and pain.

Overextension and adduction of the coxofemoral joint beyond normal ROM may lead to separation of the 
femoral head from the acetabular fossa. This separation could be due to lack of or aplasia of the ligaments 
supporting the coxofemoral joint. This could be a congenital condition which predisposes the joint to its 
current confirmation.