The kneecap dislocation is a problem affecting a great number of dogs, especially small-sized dogs. This is usually a congenital problem that gets more and more serious as time is passing by, although sometimes it is an acquired problem.

The most affected breeds are the small-sized ones, especially Yorkshire Terriers, Carlinos, West Highland White Terriers, Pinschers and Chihuahuas, and often it goes together with other diseases like hip displasia or avascular necrosis of the femur’s head.

This disorder happens when the kneecap jumps out of its natural space inside the femur inwards or outwards of the knee joint. Sometimes kneecap dislocation takes place in the inner side of the knee and exceptionally, especially in big-sized dogs, in the outer side of the joint. There are several reasons for this disorder to happen, but basically it is caused by a lack of depth in the cavity of the kneecap ligament that joins the kneecap with the top of the tibia where it is inserted.

There are four stages for the kneecap to come back to its usual place when there is a dislocation of this kind.

The clinical signs of this problem are quite easy to find and many readers will have seen animals with these symptoms in the streets. Generally, these animals can walk normally until they suddenly start hobbling for two or three steps before they can walk normally on their leg again. This is because the knee gets twisted and the animal can’t stay on that leg. If we could see them in slow motion we would see how they stretch their leg until the knee is in its right place again and they are able to walk again. When the dislocation is in the third or fourth stage and the kneecap is most of the time out of its place, hobbling is quite obvious and permanent.

The solution of this problem is always surgical. We recommend operating all the dislocation as soon as any clinical sign happens. The operation is relatively easy and solves the problem easily. Probably, this is one of the most common orthopaedic operations due to the great amount of affected dogs. We do an average of three operations on kneecap dislocation each month at our clinic.

This operation consists of moving the top of the tibia, where the kneecap tendon is inserted, towards one side if the dislocation is medium, or inwards, if it is lateral. The piece of bone removed is fixed by some steel needles that generally are never taken out. If we see that the wrinkle is flat, we dig into it with a piece of bone. However, we sometimes find animals with dislocation in the fourth stage have already caused serious disorders in the bones axes. At that point, the surgical correction will be more complex since muscles will have to be moved and probably both the femur and tibia will have to be cut.

Such aggressive and bad prognostic interventions could be avoided if these dogs were operated at the initial stages of the disease.

Article written and supplied by Paco,

Clinica Veterinaria Puerto de Mazarrón.