A cruciate ligament tear in dogs often comes out of the blue. Just now the dog is jumping happily after his ball, suddenly you can hear him yowling and he hobbles on three legs. No injuries can be seen externally.
The cruciate ligament tear is one of the most common causes of hind leg lameness in dogs. Around 20% of hind leg lameness that require veterinary treatment is caused by a tear in the anterior cruciate ligament in the dog’s knee.
While a cruciate ligament rupture in humans is usually the result of an accident, in dogs this injury is usually the result of a wear and tear disease in which the ligament gradually becomes thinner and weaker until it finally breaks with minimal stress. The causes of this material fatigue are not yet known. Since the cruciate ligament of the other hind leg also tears in around 60% of patients within a year after the first cruciate ligament tear, there are some arguments in favor of hereditary predisposition.
In fact, certain breeds, such as Golden and Labrador Retrievers, Newfoundlands, Rottweilers, Bulldogs, Bull Terriers, and Boxers, are affected significantly more often than others. In principle, however, dogs of other breeds can also suffer a cruciate ligament tear. Large, heavy, or overweight dogs with steep knee joints or bow-legged legs are particularly prone to this injury.
Large dogs are more likely to tear a cruciate ligament. © stock.adobe.com / Grigorita Ko
The rupture of the cruciate ligament is briefly associated with severe pain in the knee, as a result of which the freshly injured animals did not strike the affected hind leg. The knee joint is usually swollen after the cruciate ligament tear. Some dogs spread their injured, aching knee like a frog while sitting. Over time, the symptoms will usually decrease and the dog will no longer paralyze as badly. The lameness can get worse again in stages. In retrospect, once the diagnosis has been made, many owners remember that their dog was lame from time to time even before the cruciate ligament rupture. The slight lameness in advance can be the first symptoms of instability in the knee due to the worn cruciate ligament and the onset of osteoarthritis.
If a cruciate ligament rupture is suspected, the vet tries to push the lower leg forwards in relation to the thigh. If this succeeds, one speaks of the drawer phenomenon, which is considered evidence of a torn cruciate ligament. If the muscles are very strong, the joint capsule is hardening or the ligament is not completely torn, the drawer phenomenon sometimes does not work. In these cases, a joint endoscopy, a so-called arthroscopy, or an MRI (magnetic resonance imaging) may be necessary to make a reliable diagnosis. If knee surgery has to be performed, the vet usually refers the dog to a veterinary clinic that specializes in orthopedic surgery.
Usually a cruciate ligament rupture has to be operated on. Surgery can only be avoided in slim, small dogs with uninjured menisci. As part of conservative therapy, the animals are given anti-inflammatory painkillers and are only allowed to be moved on a leash for a short period of six weeks. Physiotherapeutic applications complement the therapy. It is hoped that the scarring of the capsule will stabilize the knee and that the dog will be able to move painlessly again after the treatment.
There is no alternative to the operation of the cruciate ligament tear:
Various surgical methods are available. The decision for a surgical method depends on the age, height, weight of the patient and the further damage to the joint.
1. Capsule tightening / Tighttrope®
With a capsule tightening or Tighttrope®, the joint is stabilized from the outside. The ligament replacement method stabilizes the knee from the inside. As a rule, both methods can only be carried out successfully on dogs of medium-sized or larger size and are not suitable for large and / or heavy dogs, because the forces that act on the knee joint are great in these animals and can lead to ligament replacement as well rips.
2. Tibial Plateau Leveling Osteotomy (TPLO) and Tibial Tuberosity Advancement (TTA)
For large, heavy dogs, interventions that alter the biomechanics of the knee are recommended. With the Tibial Plateau Leveling Osteotomy (TPLO) or the Tibial Tuberosity Advancement (TTA), the surgeon brings the bones into a different position to one another. This stabilizes the joint and ensures that the biomechanical tensile and shear forces that act on the joint are absorbed and weakened. Usually the dogs are allowed to go home after a night in the veterinary clinic for convalescence.
A cruciate ligament rupture usually requires surgery. © stock.adobe.com / alexsokolov
In the first two weeks after the operation, the dog should be spared so that the wound can heal in peace. That is, daily walks should be limited to doing business. Of course there is a line obligation. In consultation with the veterinarian, you can support the healing process with gentle measures, such as elevating the knee or cold packs against the swelling.
The prerequisite for this, however, is that the dog participates voluntarily, because any resistance on the part of the dog increases the risk of complications in the healing process.
After pulling the strings, the dog’s exercise program can be increased very slowly.