Injury to the cruciate ligament is characterized by tearing of the cranial cruciate ligament (one of the stabilizing ligaments of the knee or stifle joint). Tearing of the ligament may be due to trauma or because of degenerative changes in the ligament.

Complete tearing of the cruciate ligament results in sudden onset of severe hind leg lameness (with little or no bearing of weight on the leg). Partial tearing may result in more subtle lameness.

If you observe these symptoms in your dog, contact your veterinarian.