Reviewed and fact checked by Bruce Whittle, DVM
What is the cranial cruciate ligament and what is its purpose?
One of the more common causes of lameness in dogs is cranial cruciate ligament rupture (CCLR). In humans this condition is referred to anterior cruciate ligament rupture. This ligament is found in the stifle (knee joint) and attaches from the back of the femur (upper leg bone) to the front of the tibia (lower leg bone). This ligament, when normal, prevents the tibia from being able to move forward (cranially) in relation to the femur. When the cranial cruciate ligament (CCL) becomes partially or completely ruptured, the tibia can then move forward out of its normal position causing the joint to become unstable. This also puts pressure on other structures of the stifle such as the meniscus, other ligaments and the cartilage covering of the bone.
Are dogs of some breeds more likely to rupture their cranial cruciate ligament?
Certain dog breeds, especially those that are large and athletic are more likely to rupture their cranial cruciate ligament:
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Labrador Retrievers
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Golden Retrievers
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Rottweilers
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Akitas
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Saint Bernards
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American Staffordshire Terriers
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Newfoundlands
A hereditary aspect is suspected in Labrador Retrievers but more study is required in them as well as other breeds to confirm. Spayed female dogs also appear to experience CCLR more frequently. Because all dogs have the same basic anatomy, dogs of any other breed can also experience cranial cruciate ligament injury, especially when they are overweight, even a short-legged Dachshund who jumps off the couch and lands wrong. A recent study comparing agility dogs that experienced CCLR compared to those who had not showed that dogs who were more physically fit due to core balance and strength training on a regular basis had a lower incidence of CCLR.
Why does cranial cruciate ligament rupture occur?
Cranial cruciate ligament injury usually occurs acutely which means suddenly, as opposed to a condition that develops slowly over time. Twisting a hind leg when running or jumping down from a height are common reasons for the injury. When your dog becomes suddenly lame in a hind limb it is important to have your veterinarian examine your dog right away because there are several different causes of sudden hind limb pain other than CCLR, including fracture, rupture of other ligaments, muscle strain or luxation of the hip joint meaning the ball of the hip comes out of its socket. Waiting several days to get a diagnosis can lead to further damage to the leg, depending upon the condition, which can worsen the long-term treatment success rate. Diagnosis is based upon careful palpation and movement of the affected leg as well as radiographs to make sure there is not a different problem. Radiographs cannot evaluate whether there is a partial or complete rupture of the CCL.
What can be done to help my dog if he ruptures his cranial cruciate ligament?
Once cranial cruciate ligament rupture is diagnosed, a therapy plan can be made. In minor cases in smaller dogs, administering pain medication and controlling exercise can be successful. You should not give your dog a pain medication until you have consulted with your veterinarian, however, especially a human over-the-counter medication. Complementary therapies such as laser therapy and acupuncture can also be helpful at reducing pain and swelling. Custom othotics can be made for your dog and usually require making a cast of the affected leg and sending it to an orthotic company so a device can be built that specifically fits your dog. This orthotic device helps stabilize the joint during activity to allow the tissues to heal.
In severe cases, especially in larger dogs, surgery may be necessary. There are a few different surgical techniques that can be used depending upon your dog and surgeon preference. The simpler techniques involve placing a permanent heavy suture on the outside of the joint (extra-capsular) that basically takes the place of the injured ligament to hold the tibia in the proper position. Other procedures referred to as osteotomy procedures include Tibial Plateau Leveling Osteotomy (TPLO) or Tibial Tuberosity Advancement (TTA). In these procedures, part of the tibial bone (the lower leg bone) is cut off, moved to a different position that holds the joint in a better position, then screwed or plated in place to heal in the new location. Because there are structural implants used to hold the bone in place, there is the potential for implant failure or infection, necessitating a follow-up surgery. Generally, complications are minimal when these procedures are performed by an experienced surgeon.
Summary
Cranial cruciate ligament rupture is a very serious injury. Dogs that are more susceptible should receive ample exercise to keep muscles strong to help prevent injury as well as to keep them at a healthier weight that also decreases the risk. The only way to truly prevent cranial cruciate ligament injury would be to not let your dog do anything but that would not be much of a life. It is very important to have your veterinarian examine your dog if he or she has a sudden lameness of a hind leg. He or she can help you determine a good treatment or rehabilitation protocol for your individual dog once the diagnosis is made.
