The cause can be traumatic, or can occur as a result of chronic inflammation in the knee joint. There may be no known cause to the inflammation. However, the ligament may rupture as a result of the following diseases: medial patellar luxation, a disease in which the kneecap pops in and out of joint; rheumatoid arthritis; lupus; immune mediated polyarthritis; septic arthritis, an infection in the joint; osteochondrosis, which is a cartilage development problem; and problems related to the animal's build or body conformation.
Dogs that are obese are much more likely to develop this disease than dogs that are of normal weight. In addition, certain breeds are more prone to developing the disease, especially the rottweiller and cocker spaniel.
