Signs and symptoms vary by age group. In infants, you might notice that one leg is longer than the other. Once a child begins walking, a limp may develop. During diaper changes, one hip may be less flexible than the other. In teenagers and young adults, hip dysplasia can cause painful complications such as osteoarthritis or a hip labral tear. This may cause activity-related groin pain. In some cases, you might experience a sensation of instability in the hip.