What is Cranial Cruciate Ligament (CCL) disease?
The CCL (cranial cruciate ligament) is akin to the ACL in people but there are some anatomical differences which influence how a ligament tear occurs and how it is treated. The primary function of the CCL is to prevent the tibia (shin bone) from sliding forward under weight-bearing forces. This is called tibial thrust or cranial drawer sign, which indicates an unstable knee.
The CCL has other functions such as preventing hyperextension of the knee and restraining internal tibial rotation, but the tibial thrust is the primary cause of discomfort in dogs with partial or complete tears. Dogs frequently develop CCL tears in a degenerative manner, like a rope fraying over time. You can see subtle, intermittent lameness prior to a sudden increase of limping as the tear progresses from partial to complete. In other cases, the ligament tears can occur in an acute, traumatic fashion.
Surgery is the recommended treatment in pets with CCL tears. The goal of any CCL surgery is to restore stability to the knee. The most common surgery performed in dogs is tibial plateau leveling osteotomy. In small dogs and cats, lateral fabellar suture (extracapsular repair) is sometimes recommended.
More information is available at: https://www.acvs.org/small-animal/cranial-cruciate-ligament-disease
Frequently Asked Questions
Can dogs and cats get meniscal tears?
Yes they can, typically secondary to a CCL tear. If a meniscal tear is present at the time of surgery, the torn part of the meniscus is removed. Late meniscal tears (tears that occur after a TPLO) can occur in < 5% of cases.
Can cats get CCL tears?
Yes they can, but less commonly than dogs. Typically these occur as a result of trauma, such as jumping down or falling.
Can a CCL heal on its own?
No. The ligament will not heal on its own due to poor blood supply. Some dogs will learn to compensate and adapt, meaning the grade of lameness may decrease over time. Unfortunately, chronic lameness and pain result when the joint is not surgically stabilized.
Do CCL tears cause osteoarthritis?
Yes, the combination of the inflammation of the joint and abnormal cartilage wear secondary to instability cause arthritic changes in the joint. Surgery stops or significantly slows the progression of arthritis, but arthritis cannot be reversed once it occurs. The degree of osteoarthritis correlates with the duration on injury prior to surgical stabilization.
Is a CCL tear painful?
Yes. Limping is a major indicator of pain. If a tear is acute and traumatic, you may notice other signs of pain such as whimpering or depression. Many tears occur gradually, however, so the only sign of pain may be lameness.