Severe arthritis involves thinning and eventually a complete loss of the cartilage layer covering the ends of bones (that smooth, shiny white cap on the ends of chicken bones is cartilage). Once lost, cartilage is difficult to repair, in a large part because it has no direct blood supply. The bone immediately under the cartilage, the subchondral bone, also has a poor blood supply.
To overcome this problem, one surgical approach is a technique called microfracture. Small holes are drilled into the subchondral bone until the bone with better blood supply is reached. This procedure can help, but it only has a reasonable success rate with small areas of cartilage loss.
A recently published study from Cornell University looked at the effects of adding concentrated bone marrow to the microfracture technique. They created large (over half an inch) defects in cartilage surgically, then treated the exposed bone by microfracture alone or microfracture with concentrated bone marrow harvested from the horses’ own bone marrow. The horses treated with the bone-marrow concentrate had far superior healing.
Care must always be taken when comparing surgically created joint problems to natural arthritis. Arthritic joints have a high level of inflammation, abnormal joint fluid and likely have weakened muscular and connective-tissue support systems, plus conformational or hoof imbalance factors that caused the arthritis in the first place. That said, the results were so much better with the bone-marrow concentrate that this needs to be tried on natural arthritis cases.
Several other sophisticated approaches such as stem-cell harvesting and platelet-rich plasma are also under investigation. A clear advantage of the concentrated bone marrow is price. All that needs to be done with the horse’s bone marrow after harvesting is to spin it down in a centrifuge. Bone marrow is a rich source of stem cells and growth factors. Eventually, this may prove to be effective even without the microfracture surgery and at substantial savings to owners.