{Syndicated content copyright 2008 Fran Jurga's Hoof Blog and www.hoofcare.com}"Incorporation of more advanced analysis systems in recent years has provided veterinarians with abundant new information related to the various effects of common shoeing and farriery techniques on foot and lower limb biomechanics. It is quite obvious however, that some aspects are still controversial or unclear. Among these controversies are the effects of change in heel height on the angles of the PIP ("pastern") and MCP ("fetlock") joints and on the strains of the flexor tendons and SL ("suspensory ligament").
"Comparisons of unshod and shod horses are rare, but the use of analysis systems, such as the pressure mat, may help to clarify debate about the purported benefits of shoeing horses versus leaving them barefoot. Fine (finite element) analysis of the distal limb seems to be limited by the complex anatomy. Indeed, it seems that a full understanding of the function of smaller structures, such as the distal sesamoidean or collateral ligaments, may only be achieved with the use of computer simulation.
"Finally, it should be noted that from an evidence-based perspective, most studies that have been performed evaluating the biomechanical effects of the common shoeing and farriery techniques have been performed using sound horses, and many others have been in vitro studies. Thus, although the information obtained from such studies is interesting, its direct clinical relevance is speculative and the strength of evidence is not as strong as is desirable. "
--from the summary of the paper "An Evidence-Based Assessment of the Biomechanical Effects of the Common Shoeing and Farriery Techniques" by Ehud Eliashar, BSc, DVM, MRCVS, published in Veterinary Clinics of North America: Equine Practice, in August 2007.
Translation: when it comes to hoof research, "evidence-based" is a relative term. The same sentiment was voiced at the Fourth International Equine Conference on Laminitis and Diseases of the Foot by Rustin Moore DVM PhD DACVS in his lecture "Evidence-Based Treatment for Laminitis".
For years, many respected voices have called for a standardizd protocol for foot research. We are expected to accept as gospel studies performed on treadmills. Bar shoes or wedges tacked on to only one front foot. Horseshoes nailed onto untrimmed, unbalanced feet. Shoes tested on ponies instead of horses. Raceplates on high-heeled non-racehorses. Shoes applied for testing without following manufacturer recommendations. And, in almost all studies, the lack of control data of the horse without shoes, or at least with normal flat shoes. Contrary data even exists as to whether horseshoes dampen or increase concussion.
Dr. Eliashar's paper points out changes in study results on the same condition when the horse is on a treadmill and controversies over interpretation of statistics on toe grab relevance in racetrack breakdowns.
Looking ahead, it makes sense to draw parallels between the struggles between Darwinism and creationism when comparing the arguments for the benefits of shoes vs natural (shoeless) trimming. When scientists like Eliashar and Moore are cautious about labeling existing scientific data as "evidence-based", the boat has some serious leaks.
For years, researchers like Chris Pollitt have asked, "How do you expect us to explain laminitis when we don't know how the normal foot metabolizes and grows and functions?" Researchers like Robert Bowker have mused, "I discovered this really interesting facet, but I don't know what it might mean..."
Kudos to those willing to admit that the function of the foot of the domesticated horse is still a mystery and that science doesn't have all the answers. Science may not have even been asking the right questions.
Happy new year, anyway!
Photo courtesy of Royal Veterinary College.
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