Hip dysplasia is a term used to describe an abnormal hip joint in which there
is laxity (looseness) between the femoral head and the acetabulum (cup).
This developmental abnormality typically leads to secondary changes of the
joint including thickening of the joint capsule, flattening of the femoral
head, and osteoarthritis of the joint. Some dogs can lead normal lives with
hip dysplasia and the secondary arthritic changes caused by it. Other
dogs will become lame at a young age from the joint pain. Lameness in older
dogs is typically due to bone-on-bone contact caused by the chronic, severe
osteoarthritis.