The rupture of the cruciate ligaments is a common condition in dogs. It mainly concerns the cranial cruciate ligament. The latter ensures good stability of the knee and its rupture, partial or total, will cause the appearance of a lameness of the limb concerned.
A little anatomy ...
As in man, the articulation of the knee of the dog comprises two crossed ligaments whose role is to ensure the stability of the joint. Each of the two ligaments has one attachment on the femur and another on the tibia.
The main function of the cranial cruciate ligament is to prevent the forward movement of the tibia with respect to the femur.
Circumstances of cranial cruciate ligament rupture
In men the rupture of the cruciate ligaments occurs, most often, after an important trauma especially during the practice of certain sports (skiing, football, baseball ...)
In the dog, this condition can also occur as a result of a "bad movement" during a phase of intense play or a badly carried out sporting activity. However, these acute trauma are not the main cause of rupture of the anterior cruciate ligament. Indeed, this rupture frequently occurs without any prior trauma being noted. It is then secondary to a progressive weakening of the various constituents of the joint.
Certain factors predispose to rupture of the anterior cruciate ligament:
Obesity: the bigger the animal, the greater the tension on its ligaments
Sedentary lifestyle: very little physical activity and therefore a very rare stress on articular structures weakens cross ligaments
A chronic luxation of the patella: dogs of small breeds often suffer dislocation of the patella. The latter causes chronic inflammation of the joint and changes in the forces exerted on the ligaments, the fragilizers.
Finally, osteoarthritis of the knee is a factor favoring this pathology.
The rupture of the cranial cruciate ligament is accompanied very frequently by concomitant lesions of the meniscus.
- Traumatic ruptures of the cranial cruciate ligament may involve animals of all ages. The dog then presents a very limp limp of the limb just after the trauma.
- Secondary ruptures of a degenerative phenomenon are found in middle-aged animals (6 years old, age at which osteoarthritis may already be present) or older. It causes a more progressive lameness, not related to a specific trauma.
During the clinical examination, the veterinarian reveals a pain when he presses on the knee or mobilizes and can notice swelling of the joint
The confirmation of rupture of the cruciate ligament can be done by several methods:
During the Manipulation:
As indicated, the cranial cruciate ligament prevents the tibia from advancing relative to the femur. Upon rupture of the ligament, this "advance" becomes possible.
By practicing appropriate manipulation, the veterinarian can demonstrate this abnormal mobilization of the tibia with respect to the femur. This is called the "drawer sign"
This "sign of the drawer" is unfortunately not always present, especially when the inflammation and swelling of the knee limit its manipulation, during associated lesion of a meniscus that can distort the examination or even when only partial rupture of the ligament .
Radiography will detect signs suggestive of osteoarthritis or even diagnose a complete rupture of the anterior cruciate ligament (the ligaments are not directly visible on the plate but the radiograph taken in a suitable position may show an abnormal position of the tibia relative to To the femur). On the other hand, this method does not make it possible to demonstrate the partial ligament ruptures.
On ultrasound, inflammation of the articular membranes can be demonstrated and the cranial cruciate ligament visualized. Thus, suspicion of cranial cruciate ligament rupture will be confirmed and partial ligament rupture can be detected.
MRI allows not only accurate visualization of cruciate ligaments but also meniscus of the knee, which is very interesting considering that ruptures of the anterior cruciate ligament are very often associated with meniscal lesions.
Arthroscopic examination is performed under general anesthesia. It consists of introducing a miniature camera inside the joint to visualize all the structures. It has several interests:
- It allows to confirm the diagnosis of rupture of the cruciate ligament,
- It allows to see the meniscus and see if they are harmed
- and if the diagnosis is confirmed, the surgeon can treat the rupture of the ligament during the anesthesia of arthroscopy.
Diagnosis and surgical treatment are then feasible at the same time.
The treatment of anterior cruciate ligament rupture is surgical.
The operation must be able to stabilize the joint during walking.
Several methods can be used. The surgeon will decide which is the most suitable for each case.
The surgery consists of:
Either replace the ligament with a prosthesis.
The prosthesis may be placed inside or outside the joint and will perform the functions of the ruptured cruciate ligament. It can be synthetic or biological.
Either to stabilize the knee joint only to support it. For this, a part of the tibia will be cut and repositioned using plates and screws in a slightly different orientation. These modifications will make it possible to eliminate the tension to which the cranial cruciate ligament is usually subjected when the animal is supported on its posterior member.
The abnormal advancement of the tibia at each support is therefore eliminated without even needing to replace the ruptured cranial cruciate ligament.
Whichever method is chosen, an exploration of the inside of the joint is systematically performed in order to observe the meniscus and to be able to remove some parts which may be damaged.
After the surgery, your companion must remain in complete rest and in a confined space for a period of several weeks to avoid any stroke, any jump that can prevent a good healing of the joint (the surgeon will indicate precisely these delays in Depending on the surgical method used and the starting lesions).
Anti-inflammatories will help manage pain.
In the early days, walks will be limited to short leash trips for the animals to make their needs, then the duration of these walks will increase and a gradual and controlled re-entry of the exercise can be undertaken. Examinations and X-rays of control will be performed by the surgeon to ensure the normal course of the surgical follow-up.
In addition, careful monitoring of the weight of the animal will be carried out in order to limit any overweight, which as we have seen, is a factor promoting cross ligament ruptures.
Finally, the second knee of the dogs for which osteoarthritis seems to have been the factor favoring ligament rupture can be regularly checked by your veterinarian to ensure that there is no abnormality.
The rupture of the cranial cruciate ligament is a frequent pathology in particular in animals too sedentary or overweight. Respect for a healthy lifestyle, regular physical activity and monitored feeding may limit the risk of developing this condition.
In the face of your companion's persistent lameness, it is advisable to consult your veterinarian quickly because the rupture of a cruciate ligament very quickly generates important lesions of osteoarthritis.