Cranial cruciate ligament tears, also known as anterior cruciate ligament (ACL) tears, represent the most common small animal surgical problem dogs face today. The cause of this ever- increasing problem remains elusive, although chronic biomechanical wear associated with the canine tibial plateau slope seems to be a common denominator. Left untreated, the problem is gradually debilitating and leads to a high incidence of tearing the opposite side. All breeds can develop ACL tears. Limping and sitting to the side are the main clinical signs. Tentative diagnosis is based on palpation and radiographs. Definitive diagnosis should always be made using an arthroscope at the onset of surgery. Most surgeons agree the TPLO surgery yields the most consistent positive results.
In dogs the anatomical term is Cranial Cruciate Ligament, but because most people are familiar with the human terminology, ACL will be used for this discussion.