A degenerative disease of the bone and cartilage in the joint region. It known as a developmental orthopaedic disease as it is caused by disturbances in the process of growth associated enchondral ossification (the cartilage on the growth plates and in the joint region turning into bone). It is considered a multifactorial disease (a combination of causes leading to its development), with possible causes including rapid growth, overnutrition, mineral imbalance, and biomechanics. The most frequent presenting signs are lameness and a distended joint.