Cranial Cruciate Ligament
The CrCL is composed of two bands, a craniomedial band and a caudolateral band. It functions to stop cranial (anterior) movement of the tibia with respect to the femur, hyperextension of the stifle joint and internal rotation of the tibia. The cranial cruciate ligament is thought to be able to resist a force equivalent to four times the weight of the dog before it ruptures, but often the ligament is weakened by arthritis that is present in the joint. Arthritis infers inflammation of the joint; in this condition there is the production of a joint fluid that is less viscous and therefore less able to absorb shock than normal fluid. Joint fluid's other role is to provide nutrition to the cartilage and the cruciate ligaments. The situation is a little like a chicken-and-egg scenario: it is usually accepted that the CrCL ruptures because arthritis has caused the ligament to weaken because of poor joint fluid characteristics, but what causes the arthritis in the first place – a partial cruciate tear?
The situation is dissimilar to that seen in human athletes where overextension of the joint stretches the CrCL to failure, and replacement of the ligament with a fascial prosthesis has a good prognosis for return to full function.
Read more about this topic: Triple Tibial Osteotomy