Cranial Cruciate Ligament Injury and Surgical Repair

The Cranial Cruciate Ligament (CrCL) is a major stabilizing ligament of the knee, similar to the ACL in humans. This ligament is a strong, broad, stranded ligament located inside the stifle (knee) joint. It serves to provide forward stabilization and rotational stability during flexion and extension of the stifle. Hyperextension or excessive internal rotation of the tibia (shin bone) during heavy exercise is a common cause of a complete tear of the ligament.     
Occasionally, only part of the ligament will be torn. This partial tear still produces pain and will lead to progressive degenerative joint disease. 

Click here for a handout describing the function of the CrCL, how injuries are diagnosed, and what it means for your pet 

There are many methods of surgical fixation available for the cranial cruciate ligament-deficient stifle.  At MMVSRC, we have found great success with the Modified Retinacular Imbrication Technique (MRIT) and the Tightrope Procedure (TR).


The MRIT is an excellent choice for cats and for dogs approximately 50 pounds or less, although in some cases it is sufficient in larger dogs.  This technique employs a surgical "fishing line" that mimics the function of the CrCL and stabilizes the joint while the body lays down permanent scar tissue.


The TR may be the more appropriate choice for most larger dogs (approximately 60 pounds and above) as well as very active or high-performance dogs.  This technique also mimics the function of the CrCL, but employs the use of Fibertape, which is a Kevlar-like material that is exceptionally strong.


Popular techniques employed at other surgical facilities include the Tibial Plateau Leveling Osteotomy (TPLO) and the Tibial Tuberosity Advancement (TTA), both of which involve cutting the tibia, or the "shin bone".


We are happy to discuss the various surgical options that are available and help you decide which option is the best fit for you and your pet.




No matter which method of surgical fixation is used, strict adherence to postoperative care guidelines is essential to a successful surgical outcome for your pet.  


A 3-month period of strict exercise restriction is necessary in order for your pet's body to lay down enough scar tissue to permanently stabilize the joint.


Click here for an example of postoperative care instructions

This dog had a ruptured cranial cruciate ligament.  His knee was stabilized using the Tightrope procedure and went on to have an excellent return to function.