Dislocations

Dislocations in dogs, cats and NACs

Dislocations are abnormal displacements of a bone that partially or totally protrude from its joint socket. Although traumatic causes are most frequently mentioned, congenital or hereditary dislocations or subluxations also occur, such as in hip dysplasia or patella dislocation.

In the case of complete dislocation, the handicap is considerable, as this anomaly prevents normal movement and generates pain. In the case of incomplete dislocation or subluxation, abnormal friction between surfaces that are not designed to come into contact during movement leads to cartilage wear, inflammation and pain. The result is also a form of disability for the animal.

Traumatic dislocation

The degree of severity of dislocation depends on its origin. Traumatic dislocations are always serious, as they involve significant damage to the means of support, i.e. the anatomical structures that help hold the joint in place. These include tendons, ligaments, muscles and the joint capsule. Such damage may be irreversible, and after-effects may persist despite treatment.

Treatment of these dislocations is urgent and should ideally be undertaken within 48 hours of the trauma whenever possible.

Technically, these injuries can involve all the joints of a limb, but also the vertebrae, the jaw, the pelvic bones, etc.

In rare cases, the reduction can be reduced by manipulation and stabilized with splints. In many cases, however, surgery remains the treatment of choice.

Dislocation of the patella

The patella is a small, mobile bone that extends from the quadriceps femoris. It slides over the femur during knee extension and flexion movements. Naturally, it slides along a single axis, but occasionally the patella may come out of its socket and end up on the inside or outside of the knee. This position is obviously abnormal, causing discomfort and sometimes pain. This dislocation may be occasional, intermittent or permanent, depending on its degree of severity. This anomaly is mostly found in small dogs, more occasionally in larger dogs, and rarely in cats and rabbits. The most common breeds are the Yorkshire terrier, the Chihuahua, the Bichon Frise, the Pomeranian, the Poodle, the Cavalier King Charles, the Miniature Pinsher...

Different stages are described:

• Stage 1 : the kneecap luxates when you try to dislodge it. Lameness is rare. It returns to its natural position.
• Stage 2: the patella luxates spontaneously and intermittently. When the patella is replaced, it remains in place when the knee is immobile.
• Stage 3: the patella is permanently dislocated. It is possible to reposition it, but it instantly relocates.
• Stage 4: the patella is permanently dislocated and cannot be replaced.

Stages 3 and 4 require surgical correction. Sometimes surgery is indicated in stage 2, when pain is present. To find out about treatments for patella luxation, click here. (link to patella dislocation surgery page)

Shoulder dislocation

Shoulder dislocation corresponds to abnormal movement of this joint, which becomes partially dislocated. It is a sign of instability between the scapula and the humerus, which may be congenital, traumatic or due to wear and tear of the joint over time.

This instability is responsible for abnormal wear of the joint surfaces, and abnormal tensioning of the shoulder muscles and tendons. Inflammation and pain then set in, resulting in occasional lameness of the forelimb concerned, which becomes increasingly frequent as the anomaly progresses. Eventually, irreversible osteoarthritis develops. In the most advanced cases, muscle wasting is observed in the shoulder area.

This anomaly affects both small and large dogs. Some breeds are more affected than others by congenital shoulder instability, such as Pinshers, Poodles, Pomeranians, Chihuahuas, Lhasa Apsos, Cavaliers King Charles, etc.

How can I tell if my dog suffers from shoulder instability?

If your dog has occasional, intermittent or permanent lameness of one of its front limbs, it may be suffering from shoulder instability. In this case, it's important to have your dog examined by your vet. Your dog's shoulder will need to be manipulated to check that the joint's range of movement is normal. The most frequent instability is in the medial (inner) part of the joint.

An X-ray examination is often recommended to check for osteoarthritis of this joint, which usually indicates the age of the problem. It can also be used to check for other abnormalities in the joint that may be unrelated to instability or dislocation.

Arthroscopy is also an interesting examination for assessing this joint. It allows us to visualize the ligaments (glenohumeral medial) and check their condition. It can also check the state of the articular cartilage and the presence of osteoarthritis, which has prognostic value.

How do I treat my dog's dislocated shoulder?

The ideal treatment is surgical. It aims to correct instability by using certain tendons, shortening certain ligaments, using prostheses... Arthroscopic treatment techniques are being developed, and appear to give encouragingly better results than traditional techniques involving transposition of the biceps tendon.