An almost everyday situation: The four-legged friend enjoys the trip together with us, runs happily across the meadow. Suddenly he does not step up with one of his hind legs and hobbles on three legs in our direction, seeking help. As with us, the first shock, so also lies with him soon the first pain, and arrived home, everything seems only half as bad. Nevertheless, we notice in the next few days again and again a slight lameness. Unrest is spreading, because we know that cruciate ligament rupture is one of the most common injuries in dogs. “My PET” spoke to Prof. Britta Vidoni from the Vetmeduni Vienna Small Animal Surgery about diagnostic and therapeutic options.
For the dog owner, it is difficult to classify whether a sudden lameness of the dog is a harmless strain, or whether a cruciate ligament tear could be a more serious injury behind it. When is the way to the vet indicated?
Prof. Britta Vidoni: Any lameness that persists after a few days of medication must be clarified. The diagnosis of a cruciate ligament rupture is sometimes relatively difficult. In general, the affected dogs show lameness on the hind limb. The more chronic this lameness is, the more difficult it is for the vet to detect a cruciate ligament tear. A first indication is swelling of the knee joint due to increased joint filling. Then the joint is examined with special orthopedic provocation samples.
Does this include the “drawer handle,” which is often heard in connection with the cruciate ligament tear?
Prof. Britta Vidoni: Yes! The “cranial drawer” is one of those provocation specimens in which you want to move the lower leg against the thigh bone forward. This is only possible if the anterior cruciate ligament is torn and can no longer fulfill its task of guaranteeing stability in the knee joint. In chronic processes in the joint, but also in heavy dogs, this drawer is often extremely difficult to trigger. Another type of provocation is the “tibial compression test”, which imitates the strain on the foot. Thus, the lower leg bone, the tibia, in turn has the ability to dodge forward, which only happens when the cruciate ligament is torn.
Tibia is the medical name for the lower leg bone (tibia). The tibial plateau is the entire upper surface of the bone that lies in the knee joint. (Editor’s note)
An x-ray does not help diagnose the cruciate ligament tear further?
Prof. Britta Vidoni: The X-ray shows only the secondary signs of a problem in the knee joint. If there is an instability lasting about six to eight weeks, you will see first arthroses that develop very quickly. In addition one sees on the X-ray image an increased knee joint filling, but the torn cruciate ligament itself can not be seen, of course, because an X-ray shows only the bone structures or in the case of soft tissue thickening and changes. These secondary signs give us additional clues that something is wrong in the knee joint, but the cruciate ligament tear still remains a question mark. A safe diagnosis is provided only by magnetic resonance imaging or arthroscopy, a minimally invasive procedure in which we can look into the knee joint and assess the cruciate ligament as well as the menisci.
Does this procedure only serve the purpose of diagnosis or is it possible to do therapy with arthroscopy at the same time?
Prof. Britta Vidoni: In the knee joint, arthroscopy can be used to treat a torn meniscus. One can rinse the joint and remove some ligament remains, but stability in the knee can not be achieved primarily with arthroscopic surgery. That is the goal! Simultaneous presentation of tibial plateau angle measurement Use of arthroscopy for diagnosis and therapy, such as OCD (osteochondritis dissecans), where a local cartilaginous bone defect is diagnosed and arthroscopically removed in the same operation, is present in the knee in the presence of instability not possible in this form. However, it is used to assist with ligament replacement techniques.
Which we would be with the therapy … Is the ligament replacement today still a common surgical method?
Prof. Britta Vidoni: No, the cause is different – either traumatic or degenerative. In the dog, it is mostly bagatelles. He jumps out of the car like every day and suddenly gets lame. In the course of a degenerative process, the ligament is successively weakened until it breaks and then can no longer fulfill its function as a stabilizer of the knee joint. The reason for this may be the multiple movement possibilities of the knee joint, which could strain the band tremendously and could be a reason for the degeneration. Obese dogs are more likely to be affected. In addition, a steeper tibial plateau is certainly a predisposition for a cruciate ligament tear. And with that we come back to your question Therapy with ligament replacement. These band replacement techniques work the less the steeper the plateau is. Because there is too much force on the replacement band, so that it finally breaks. Because of this, other techniques have been developed, namely the interventions in biomechanics, in which the plateau is changed over with special saw cuts in the bones in order to neutralize the force axes.
These biomechanical interventions include the TPLO methodology?
Prof. Britta Vidoni: Among other things! However, there are a variety of osteotomy options available through this 30 my pet arthritomally altered knee joint after a cruciate ligament rupture osteotomy, the tibial plateau leveling osteotomy (TPLO). All have in common the goal to neutralize the force axes in the knee joint under load and thus to achieve dynamic stability. With the TPLO, the mechanical axis is changed so that a neutralization of the forces in the knee joint arises: If the dog occurs and the knee loaded, the tibia can not move forward.
Osteotomy is a surgical method in which a bone is severed to correct malpositions or an existing balance of power. (Editor’s note)
The decision as to which surgical method is the right one depends on the individual anatomy of the patient …
Prof. Britta Vidoni: Absolutely. Especially smaller dogs with a flat tibial plateau have a good chance that the ligament replacement techniques will work. If the plateau is steeper, the tibia will relocate over time. Then you decide to maybe a Umstellungsostenotomy.
For sports dogs, a conversion osteotomy would be the method of choice?
Prof. Britta Vidoni: That would certainly be recommended. The TPLO method was developed more than 20 years ago in the USA specifically for sports dogs. Of course, the convalescence phase lasts several months. You saw a bone apart and fix it in a different position – that must heal! But if all goes well, these dogs have a good chance to do sports again.
As with all joint operations, is the time after surgery certainly crucial for success?
Prof. Britta Vidoni: Immediately after the operation, cold compresses are important, then absolute linen pressure and good pain therapy are the first steps. When the acute pain is over, targeted physiotherapy can begin, as joints need to be moved. Monthly skincare is wrong. The movement must be slowly increased until you can finally return to a normal load.