Thursday, May 23, 2013

Lameness Evaluation: American Sensor System Tests Successfully in British Research

Flexion testing, using the sensor-based system, at the University of Glasgow's School of Veterinary Medicine
For many years, opinions on the value of flexion tests in assessing equine lameness have been divided. Now, however, new research looks set to turn what has always been regarded as a subjective process into a wholly objective one. 

A comprehensive study, published in a November 2012 supplement to the Equine Veterinary Journal (EVJ) in partnership with the American Association of Equine Practitioners, showed that a wireless, inertial sensor-based system can effectively measure the horse’s response to a flexion test.

Flexion tests are used routinely in horses with subtle or imperceptible lameness, to exacerbate the problem and make it apparent to the observer. The test involves applying a short period of pressure to the joints of the limb before re-examination, and evaluating any change in gait. However, flexion tests rely on the ability of the observer to identify and interpret changes in the horse’s gait: in that respect, these tests are subjective and not necessarily consistent between observers.

The research study was conducted by orthopedic surgeons based at the University of Glasgow's School of Veterinary Medicine. Seventeen healthy adult horses, all in work, were fitted with sensors before being trotted in a straight line. The sensors measured vertical pelvic movement asymmetry for both right and left hind limb strides and the average difference in maximum and minimum pelvic height between right and left hind limb strides. 

A hind limb was randomly selected for 60 seconds of proximal flexion, after which the horse was trotted for a minimum of ten strides. Response to the flexion was blindly assessed as negative or positive by an experienced observer.

John Marshall, lecturer in equine surgery at the University of Glasgow, led the study. He concluded: “A positive response to flexion resulted in significant changes to objective measurements of pelvic symmetry, supporting the use of inertial sensor systems to objectively assess response to flexion tests.”

Professor Jim Moore, North American Editor of the EVJ, continued: “The introduction of an objective approach to documenting lameness examination will not only help vets and trainers to investigate equine lameness more accurately; it will also serve as an unbiased method of communicating lameness examination findings among vets, trainers, farriers and other professionals.”

The next phase of research will be to establish cut-off values for objective assessment of other equine lameness diagnostic procedures, such as nerve blocks.

Study publication details: Use of a wireless, inertial sensor-based system to objectively evaluate flexion tests in the horse, JF Marshall, DG Lund and LC Voute, EVJ ISSN 0425-1644 DOI:10.1111/j.2042-3306.2012.00611.x

Information in this article was provided by the Equine Veterinary Journal.

More: The paper, which was published at the end of last year, is currently available online as open access to be read in its entirety. The system tested was the Equinosis system, developed at the University of Missouri.

Click here for ordering information; last copies of first edition available.

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