Without an intact cruciate ligament, the knee is unstable. What Happens if the Cruciate Rupture is Not Surgically Repaired The lameness may be acute but have features of more chronic joint disease or the lameness may simply be a more gradual/chronic problem. In this type of patient, stepping down off the bed or a small jump can be all it takes to break the ligament. The partial rupture may be detected or the problem may not become apparent until the ligament breaks completely. On the other hand, an older large dog, especially if overweight, can have weakened ligaments and slowly stretch or partially tear them. Bernard, Chesapeake Bay retriever, and American Staffordshire terrier. This is usually a sudden lameness in a young large-breed dog.Ī recent study identified the following breeds as being particularly at risk for this phenomenon: L abrador retriever, Golden retriever, Rottweiler, Neapolitan mastiff, Newfoundland, Akita, St. One is a young athletic dog playing roughly who takes a bad step and injures the knee. Several clinical pictures are seen with ruptured cruciate ligaments.
Arthritis present prior to surgery limits the extent of the recovery after surgery though surgery is still needed to slow or even curtail further arthritis development. This will require surgical repair and the surgeon will need to know about it before beginning surgery. Another reason for radiographs is that occasionally when the cruciate ligament tears, a piece of bone where the ligament attaches to the tibia breaks off as well. Since arthritis can set in relatively quickly after a cruciate ligament rupture, radiographs to assess arthritis are helpful. Eliciting a drawer sign can be difficult if the ligament is only partially ruptured so a second opinion may be a good idea if the initial examination is inconclusive. This is especially true with larger dogs. Often sedation is needed to get a good evaluation of the knee. Tense muscles can temporarily stabilize the knee, preventing demonstration of the drawer sign during examination.
It is not unusual for animals to be tense or frightened at the vet's office. This is called a medial buttress and is a sign that arthritis is well along. If the rupture occurred some time ago, there will be swelling on side of the knee joint that faces the other leg. If the ligament is ruptured, again the tibia moves abnormally forward. (See a video of this manipulation.)Īnother method is the tibial compression test where the veterinarian stabilizes the femur with one hand and flexes the ankle with the other hand. If the tibia moves forward (like a drawer being opened), the cruciate ligament is ruptured. The veterinarian stabilizes the position of the femur with one hand and manipulates the tibia with the other hand. The anterior/cranial cruciate ligament prevents the tibia from slipping forward out from under the femur. This may be hard to visualize based on the description but the illustration above shows the orientation of the two crossing ligaments effectively. They are named for their attachment site on the tibia (the cranial cruciate attaches to the front of the tibia and the caudal cruciate attaches to the back of the tibia). They connect from one side of the femur on top to the opposite side of the tibia on the bottom, the two ligaments forming an X (hence the name cruciate) inside the knee joint. There are two cruciate ligaments that cross inside the knee joint: the anterior (or, more correctly in animals, cranial) cruciate and the posterior (in animals, the caudal) cruciate. An assortment of ligaments holds everything together, allowing the knee to bend the way it should and keep it from bending the way it shouldn't. Chunks of cartilage called the medial and lateral menisci fit between the femur and tibia like cushions. It consists of the femur above, the tibia below, the kneecap (patella) in front, and the bean-like fabellae behind.