Issue # 56
www.horseracingbc.ca
November 2013
The Surgeon’s Corner…by Dr. Antonio M. Cruz DVM, MVM, MSc, DrMedVet, Equine Surgery and Sports Medicine Specialist How Can An MRI (Magnetic Resonance Imaging) Help You? Lameness costs the horse industry in North America an estimated $1 billion annually and it is the leading cause of financial loss in the racing industry. Approximately 25% of affected horses experience fetlock pain. Although cartilage disease is the focus of much therapeutic intervention in these horses (i.e. joint injections, chips, etc…), it is still uncertain whether cartilage injury is the primary and solely factor responsible for joint disease. Actually we believe that the bone beneath the cartilage is really where the pain comes from and the important player while the cartilage is an innocent bystander. Traditionally we have been unable to look at the bone with any more detail than the one provided by x-rays, so out of sight, out of mind sort of thing. X-rays while being a practical tool are clearly inadequate to image many of the changes that happen to the bone and that are responsible for a racehorse lameness. In fact over the years we have been focusing solely on the joint surface when the real problem lies just beneath it. It’s the bone! With the development of new technologies we are starting to see the real problem, not just its consequences. Some years ago, during my tenure at the University of Guelph, I reported in several scientific journals the
changes occurring to the bone in fetlock joints in racehorses using a microscopic x-ray tool called micro-CT. This research tool allowed us to see the sequence of damages that lead not only to lameness and chips but also to catastrophic fractures. We were able to see how the structure of the bone changed to the point that became vulnerable to fracture and actually fracture! We all know that catastrophic fractures in racehorses are common and seen by many as a “fact of racing horses”. But is it so? It is clearly obvious that fractures are the end-stage of a chronic problem, not just the result of a fluke accident. So is there a way that we can see the changes in the bone before it’s too late? Today with the use of MRI we can see these changes and new work by Dr. John Peloso from Florida gives a compelling story to use this technology to screen racehorses in order to identify those horses at risk of breaking down and to diagnose problems above and beyond what a radiograph may not tell you. The fetlock joint is the most common site for fracture formation in the Thoroughbred racehorse. Good evidence exists to show that these conditions develop deep to the cartilage layer in the underlying bone due to a silent process known as non-adaptive bone modeling.
The condition has two hard facts: It is difficult to identify in its early stages yet its effects are reversible if recognized early and the tools available for disease identification, namely clinical examination, x-rays, ultrasound, or a bone scan, are not sensitive indicators for the spectrum of this condition. Because MRI gives useful information about both bone MRI as a diagnostic tool structure and bone chemistry, it can be using this technique for not only screen horses ness and see the entire used to detect bone early fracture identififor future fractures, but picture, not just a piece injury in the early of it! cation. also investigate lamstages of disease, well In Dr. Peloso’s study Paton & Martin Veterinary Services Ltd. Dr. David Paton, Dr. Eric Martin before it can be identi- it becomes crystal clear Dr. Antonio Cruz and Dr. Marielle St-Laurent Full Service Hospital and Surgical Facility fied on X-rays. The • Board Certified Surgeon how horses with • Advanced Lameness Diagnostics & Treatments: PRP, IRAP, Stem Cell, availability of MRI Therapy, Mesotherapy, Physiotherapy, Acupuncture, Extracorporeal subsequent cannon Shock Wave Therapy, Cryotherapy and much more! systems for imaging • Condylar Fracture Repair, “Chips”, Throat Surgery, Colic and more! bone fractures have • Videoendoscopy (1.5 to 3 metres) for upper airway horses under standing and stomach problems (ulcers) increased MRI signal • Located 10 minutes from Thunderbird Show Park sedation and without at specific sites, again 25939 - 40th Ave. Aldergrove BC V4W 2A5 Telephone: 604-856-3351 the need for general not seen on x-rays. www.pmvetservices.com admin@pmvetservices.com anesthesia is particuTherefore it would larly beneficial for only seem logical to horses in training as use this technology to trainers and owners are very reluctant to for all your horse insurance needs anesthetize horses for a lameness diagnosis, especially during the racing season. Anesthetic death, a poor recovery from anesthesia, or recovery from general anesthesia on a limb with a hidden orthopedic fracture are all legitimate reasons for concern. MRI is identified as the imaging modality of choice for stress fracture detection in human medicine. MRI can also provide diagnostically valuable images in the standing patient so the risks of general 106 - 3701 E. Hastings St. anesthesia are avoided. Burnaby, B.C. V5C 2H6 Racing jurisdictions (604) 293-1531 FAX: (604) 293-1248 in the United Kingwww.equineunderwriters.com dom, Europe, and Dubai are currently
Equine Insurance Underwriters Ltd.
since 1980