The wrist or carpal joint of the dog differs from that of humans with the presence of a semirigid fibrocartilaginous ligament which encircles the wrist.

This ligament allows the dog to remain upright on it's forelimbs by preventing the wrist from collapsing backwards. In certain situations this ligament can rupture.

This most commonly occurs when a dog leaps down from a great height and lands on its frontlegs tearing these ligaments in the process.

It can also occur in a much more insidious manner when the wrist joint, over a prolonged period of time, degenerates due to the presence of severe arthritis.

This was the case with Zedby an elderly collie who was referred to me from Ashby de la Zouche. He had been under treatment from his own vet for his arthritis for a number of years but recently his right carpus/wrist had collapsed to the point where it could no longer support his body upright.

Once this occurs there is never any possibility of the ligament repairing and regaining its original strength. Ligaments have a poor blood supply and, due to the presence of random collagen formation, the resulting scar tissue is unable to perform the original task. Attempting to splint the leg always results in failure.

The only successful procedure involves fusing or arthrodesing all the joint surfaces within the carpus/wrist. This is a highly complex procedure which is both time consuming and expensive to perform.

A specially designed stainless steel plate is secured across all of the joints only after all joint cartilage has been destroyed or removed.

Trying to encourage bone production in an area where the patient would normally inhibit its presence goes against Mother Nature! Consequently, a bone graft is taken from the patient's own shoulder to stimulate bone fusion.

Even after all this has been performed there is a considerable wait until we can be sure that healing is complete.

It requires a special type of owner who is prepared to provide the opportunity for that process to occur. Fortunately, Zedby has such owners and so far he has been adapting to his new bionic leg with great enthusiasm which is just as well given his owner's bionic bill!

Terry Dunne BVMS, Cert SAO, MRCVS

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