These ligaments of knee joint and are responsible for joint stability, weight bearing and motion of the leg. A sudden turn, twist or a jump can cause the injury and even rupture these ligaments leading to instability, pain and even arthritis (old injury) in knee joint. Most commonly it occurs in overweight or hyperactive pets. Pet has very painful limp or non-weight bearing injured leg. Sometimes X-rays but the palpation of the relaxed knee joint (with heavy tranquilizer or even anesthesia) is essential for diagnosing the ruptured cruciate ligament. A minor cruciate injury can be managed by strictly confining the with pain medication but in severe injury a surgical repair is recommended. The post-op recovery depends on the home care restrictive management of the patient. Please make an appointment to discuss with the doctor if your pet has some knee injury at 562-630-2082 for evaluation.