Growing pains

We often associate degenerative joint diseases with horses in middle or old age, but youngsters – even foals – can present with conditions under the umbrella of developmental orthopaedic disease

- Bethany Stone

USING the term “developmental” when describing an orthopaedic disease brings forth the notion of growth and change.

This idea of transience, says H&H veterinary consultant Dr Karen Coumbe, is the crux of the matter - literally - when we consider bone, be it the bone of a foal, youngster or an older horse.

“Bone is living tissue, just like any other part of the body,” she explains. “It’s not inert; it develops and changes all the time. It is continuously calcifying, resorbing and putting down new bone - this is how fractures can mend themselves.”

Dr Richard Stephenson, Associate Professor at the University of Nottingham vet school, reiterates this point.

“Joints repair themselves all the time,” he remarks. “There are processes in the joint to remove damaged cartilage and there are other mechanisms to repair it.

“In healthy joints, these processes are in perfect balance. Where you have a degenerative joint disease [DJD], such as osteoarthritis, the joint process that removes the dead cartilage is dominant and the tissue is not renewing itself at a healthy rate.”

We frequently consider osteoarthritis to be a primary condition, developing as a consequence of chronic wear and tear.

“It can, however, be a secondary consequence of earlier joint injury, infection or developmental abnormalities,” explains equine surgeon Dr Michael de Cozar of Bell Equine Veterinary Clinic.

JOINT INFECTIONS IN FOALS

SOME of the earliest possible examples of DJD are joint infections in foals.

“These occur when a foal gets an infection systemically by the navel,” explains Dr Stephenson. “Bacteria get into the bloodstream, where white blood cells provide an effective defence.