Gait and lameness analysis - the Singapore way | Trainer Magazine | European Trainer Article Index

Dec 31

Dec 31 Gait and lameness analysis - the Singapore way

Although one of the most common issues affecting racehorses, lameness is also one of the hardest to quantify. A two-year study in Singapore aims to find out whether regular measurement of a horse’s gait can be used to predict musculoskeletal injury. WORDS: MaRia FeRnanDa SepulveDa CavieDeS pHOTOS: MaRia FeRnanDa SepulveDa CavieDeS, SHuTTeRSTOCK ECAUSE I was born under a lucky star, I was offered the sensational opportunity to conduct a two-year long study in the beautiful, hyperefficient, and very hot island of Singapore. The study ‘Early detection of musculoskeletal injury in the Thoroughbred through monitoring of movement symmetry’ started in November 2014 and is funded by the Horserace Betting Levy Board (HBLB), and it was designed by Dr Thilo Pfau together with Professors Renate Weller and Kristien Verheyen from the Royal Veterinary College in London. Traditional veterinary evaluation of lameness is subjective. Objective tools to document and measure specific forms of lameness and changes in gait are needed and will allow horses to be evaluated more consistently over time, looking for patterns of lameness developing during training. It may also be possible to predict specific sites of injury or pain based on the patterns observed with gait analysis. The idea behind this HBLB project was simple: follow as many thoroughbreds in training as possible on a monthly basis for a year and a half, tracking their soundness with a sensor-based gait assessment device at the Singapore Turf Club (STC), then correlate their medical history and their soundness/lameness in an attempt to determine which of the many gait parameters that are measured by the gait analysis system could be used to detect musculoskeletal injuries, ideally before they become clinically apparent. The venue The Singapore Turf Club is a modern racetrack with an all-weather surface and a turf track. The horses that regularly race there are stabled around it by the different trainers in similar stable blocks and are treated by the same vets at the STC veterinary clinic. Horses coming in and leaving the STC undergo stringent quarantine and veterinary checkups. Most HBLB-funded research is conducted in the UK, but for this study Singapore was chosen because it was an environment with convenient logistics allowing to test a large number of horses in training, while at the same time reducing as much as possible the variables that may influence soundness and performance (i.e. track surface, veterinary treatments, weather, etc). Very importantly, the setup allows the testing to be carried out in a real life situation and not in a lab. The gait analysis device Everybody who deals with horses knows that lameness is one of the main problems that affects racehorses, shortening their racing careers and causing the industry to lose a lot of money. Some lamenesses may be tricky to pinpoint and even the most experienced vet could have trouble localising lameness. As an answer to this, a couple of systems that detect very slight/ intermittent lameness have been developed and validated, and these can help vets use a more objective approach to detection and grading of lameness. The machine used in the project uses inertial sensors, containing miniaturised accelerometers, gyroscopes, and magnetometers and aided by a GPS device. These sensors can track movement in three dimensions and calculate the speed of the horse. These are readily utilised in the missile and drone industry … so we are talking about technology that is state-of-the-art. The system is capable of detecting differences in gait symmetry (i.e. between the stance Although one of the most common issues affecting racehorses, lameness is also one of the hardest to quantify. A two-year study in Singapore aims to find out whether regular measurement of a horse’s gait can be used to predict musculoskeletal injury. WORDS: MaRia FeRnanDa SepulveDa CavieDeS pHOTOS: MaRia FeRnanDa SepulveDa CavieDeS, SHuTTeRSTOCK The Singapore Turf Club “A couple of systems that detect very slight/ intermittent lameness have been developed and validated that can help vets to detect gait abnormalities phases of right fore and left forelimb) in the order of millimetres, and is more sensitive than the human eye in picking up these small asymmetries (Figure 2). The sensors are the size of a matchstick box (Figure 3) and are stuck to the horse simply using double-sided tape, or they can be placed in a Velcro pouch and attached to the tack, usually the surcingle and the headband on the bridle. For this study, the sensors were placed: one on the poll, one on the withers, another on the sacrum (tuber sacrale, or midline on the highest point of the croup), and one on each point of the hip (left and right tuber coxae) (Figure 4). The sensors were wired to a transmitter on a surcingle, which could then send all the data directly and instantaneously to a laptop via Bluetooth (Figure 5). The practically feasible range between horse and computer is around 50m, so it is easy to record standing at one end of a trot-up while the horse handler (or “syce” as they are called in Singapore) trots a horse in hand. The trainers, vets and horses Sixteen trainers were recruited into the study on a voluntary basis and graciously allowed some or all of their horses to undergo gait analysis once a month. The vets of the STC veterinary clinic were closely involved in the project, especially Dr Bronte Forbes, who helped coordinate many of the aspects of the data collection and treatments of the participating horses. The veterinary clinic is supervised by Dr Koos van der Berg and has state-of-theart medical diagnostic equipment, and its vets are highly trained and extremely experienced. The horses included in the study ranged in age and experience. Some were sound throughout while others became lame during the study, but all were in Flat race training at recruitment. The Singapore Gait Analysis Study At the beginning of this project, it was necessary to establish the repeatability of the gait measurement. Once we were sure that horses could be followed with the a) Lame horse on the left fore. There isn’t symmetrical weight bearing or both fore feet. The difference is of a few millimetres Figure 2: Output graph that shows a) a sound horsea; and b) a horse with a slight asymmetry in gait on the left fore. The dark blue line is the average for each stride, and the grey area is the time that the foot is in contact with the floor, bearing weight. The scale on the left is in metres Figure 3: The gait analysis sensors are the size of a matchstick box. Figure 2 Figure 3 Figure 5 Figure 4: Sensors are attached at the poll, withers, croup and hips F necessary repeatability, the study was fully ” underway. Monthly data collection sessions were arranged. Trainers were contacted a week before and coordinated my visit with them. In the sweltering heat, the horses and their syces would be waiting for me in the shade. Then over an hour or two, the manic sequence of placing the machine on the horse, trotting it, taking the machine off, and checking the data kept going without stopping. Parallel to this, medical data for each horse was compiled. Data collection is now complete and the research team are currently correlating the gait measurements to the diagnosed lamenesses. In addition to the main study, the set up in Singapore allowed us to conduct a number of sub-projects. We have compared the gait parameters generated for sound and lame horses over different surfaces. Data analysis is still under way and will ultimately help determine which surfaces aggravate or reduce a lameness. This could be helpful for vets to prescribe exercise on different surfaces during the rehabilitation process and also to choose the surface best suited for accentuating mild asymmetries in order to detect them during gait analysis (Figure 6 and Figure 7). We also compared the output of the machine with the subjective visual lameness grading by the experienced racing vets. Once data analysis is finished, the aim is to relate the gait parameters recorded by the machine to the grades of the most commonly used lameness grading systems in thoroughbreds. This will help making the gait analysis results more readily interpretable by racing vets. Future goals The final analysis of the data generated during those 18 months is ongoing. However, this project has demonstrated that it is feasible to perform regular gait analysis sessions in a training yard environment. This study is the first step towards future work evaluating links between specific objective changes in gait symmetry and injury to be able to prevent serious injuries in thoroughbreds in training or while racing. n Figure 7: Dr Bronte Forbes trotting a horse over different track surfaces

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First published in European Trainer issue 56 - January '17 - March '17

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