Do you have a large breed dog that loves to run, romp and jump? And one day you notice that your dog seems to be favoring one leg, and then limping a bit, and then suddenly your dog can’t put any weight on the leg at all? Then it’s time to visit Dr. Whitworth for a physical exam and some specialized testing to identify if your dog is presenting symptoms of a Cranial Crucate Ligament (CCL) injury. Early diagnosis is preferable over waiting until the condition becomes chronic, as arthritis may develop over the long term.
What is a Cranial Cruciate Ligament (CCL) Injury?
When a dog suddenly develops rear leg lameness, in most cases it is caused by a ruptured cranial cruciate ligament. In fact, a ruptured cruciate ligament is the most common knee injury experienced by large breed dogs. Without treatment, the leg favoring may seem to improve over a few week period, but once the condition enters the chronic stage the knee will remain swollen, and arthritis can set in.
The knee is a fairly complicated joint, consisting of long bones, the kneecap in front, the medial and lateral menisci cartilage, and an assortment of ligaments holding everything together. This construction allows the knee to bend properly. Not to get too technical, but in a dog’s anatomy, two ligaments cross inside the knee joint: the cranial (anterior) cruciate and the caudal (posterior) cruciate. The cranial cruciate ligament is located in front and prevents the tibia from slipping forward out from under the femur. This type of ligament injury usually involves the cranial cruciate ligament, but may also include damage to the caudal cruciate ligament and/or the meniscus depending on the case.
How Does the Rupture Occur?
The condition most often affects large breed dogs, and some breeds are more susceptible to ruptured CCL injury. There are two major scenarios that most often lead to a CCL injury.
Young, athletic large breed dog: This injury is usually incurred during rough play or while running. The dog may take a bad step and tweak the knee, which can cause immediate onset of lameness. The following breeds are particularly at risk for this phenomenon: Neapolitan mastiff, Newfoundland, Akita, St. Bernard, Rottweiler, Chesapeake Bay retriever, and American Staffordshire Terrier.
Older large breed dog: Older dogs, particularly those with extra pounds on their frame, may develop a partial rupture – weakened, stretched or partially torn ligaments from a combination of age and strain from the weight. If the partial rupture goes undetected, the rupture may not become evident until the ligament completely tears. Even a small everyday motion like getting off a couch or bed, or an air wriggle when you get home, and boom – the ligament tears. Rupture damage may also arise from gradual chronic age related joint disintegration, although it is often more difficult to discern. In addition, with plump older and larger dogs, a ruptured cruciate ligament usually comes in pairs. Be prepared for a rupture in the other hindquarter to occur within several months from the first.
How is a Ruptured Cranial Cruciate Ligament Injury Diagnosed?
Patton Chapel Animal Clinic is pleased to offer veterinary orthopedics services to its clients. We have our own in- house laboratory and radiology equipment to diagnose injuries and perform any followup or diagnostic tests should they be needed. In the case of a potential ruptured cranial cruciate ligament, unfortunately during a physical exam, CCL related abnormalities in the early part of the disease cycle are not readily evident on an x-ray. Instead, Dr. Whitworth conducts 2 types of tests: a cranial drawer sign and a tibial compression test.
Cranial Drawer Sign: The key to the diagnosis of the ruptured cruciate ligament is the demonstration of an abnormal knee motion called a drawer sign. It is not possible for a normal knee to show this sign. The position of the femur is stabilized with one hand and the tibia is manipulated with the other hand. If the tibia moves forward (like a drawer being opened), the cruciate ligament is ruptured. A second opinion may be warranted as a partial rupture may not exhibit the “drawer” indicator.
Tibial Compression Test: The femur is stabilized with one hand and the ankle is flexed towards the ankle with the other hand. The tibia moves abnormally forward when the ligament has been ruptured.
Radiograph: Another indication that a rupture has occurred is swelling on inside of the knee joint, called a medial buttress, which is associated with arthritis. A veterinary radiograph should be taken to assess the level of arthritis and to rule out the possibility that a piece of bone where the ligament attaches to the tibia has not broken off. The presence of arthritis has the potential to limit the extent of recovery after surgery.
What are the Treatment Options?
The knee is unstable without an intact cruciate ligament, leading to abnormal wear between the bones and meniscal cartilage. As a result, the joint begins to exhibit degenerative changes, and bone spurs may develop. No dog owner wants to subject their four legged family member to chronic pain and loss of joint motion, so surgery is recommended to repair the damage. Although there are several surgical options, there are two different surgical repair techniques that Dr. Whitworth recommends: Lateral fabellotibial suture and Tibial plateau leveling osteotomy (TPLO).
Lateral Fabellotibial Suture Technique: This surgery can be performed in-office at Patton Chapel Animal Clinic as it is less time intensive than other procedures and does not require specialized equipment. It involves opening and inspecting the knee joint, and any torn portion of the cruciate ligament is removed, as well as any bone spurs, and any damaged portion of the meniscus, if also torn. Giving the procedure its name, a large, strong suture is passed around the fabella behind the knee and exits through a hole drilled in the front of the tibia, tightening the joint to prevent the drawer motion. In essence, the suture replaces the function of the cruciate ligament.
Tibial Plateau Leveling Osteotomy (TPLO): Dr. Whitworth considers this technique more appropriate for larger dogs. Even a dog with arthritis pain from an old cruciate rupture may still benefit from a TPLO surgery. The tibia is cut and rotated so that the natural stance of the dog is employed to stabilize the knee joint. Again, the knee joint is opened and damaged meniscus removed, although the cruciate ligament remnants may or may not be removed depending on the degree of damage. Because of the complexity of this surgery, Dr. Whitworth refers his patients to a specialist trained in this technique.
What to Expect Following Surgery?
Generally rehabilitation following the surgery is similar to human recovery – except probably your furry friend doesn’t complain as much! That said – ice, rest and gentle physical therapy is the drill. Water treadmills are helpful if available. Jumping, running or stair-climbing are not allowed during recovery, which typically lasts about 6 weeks.
If you suspect that your dog has suffered a CCL, particularly an animal weighing over 30 pounds, schedule an appointment with Dr. Whitworth at Patton Chapel Animal Clinic right away. Time is of the essence to determine a diagnosis and treatment plan in order to deter further degeneration and arthritis if the condition is not treated. We are conveniently located in Hoover, Alabama, serving the Birmingham metro communities of Vestavia Hills, Mountain Brook, Cahaba Heights, Pelham, and Homewood, as well as other Jefferson County and Shelby County residents.