When a dog visits the vet the examination is made up of many factors.A history is taken. The basic measurements of temperature, pulse and respiratory rate are measured and compared to a normal range. The dog is observed and palpated. When attempting to diagnose a lameness then gait evaluation is an important facet of the whole. Veterinarians rely on observation. Watching the dog walk and/or trot in a straight line, away from and towards the observer is standard practice. The veterinarian then takes note of the presence or absence of lameness, the head position, the way the limbs move in relation to each other, the position of the tail to name only a few aspects of the observation. The fluidity of the movement is also noted. Observing the gait in this manner is subjective and relies heavily on the experience of the person observing.
Objective ways to measure the gait are available. These include force plate analysis, kinematic studies and pressure mat systems. These systems provide a great deal of information to researchers and academic based clinicians. These methods are, however, expensive and often only to be found in academic institutions.
Identifying gait asymmetries or lameness in animals often requires more than just a visual assessment. Animal Health and Hydro has access to a pressure sensor walkway manufactured by Tekscan Systems, called the Strideway. This system has the ability to capture multiple sequential steps for analysis of paw function and gait. Objective data provides the ability to determine precisely which paw or limb is problematic and allows for easy monitoring of progress. It is as simple as walking over a mat. The information gathered from sensors in the mat are saved into a computer program which then analyses the data and produces graphs and tables from which comparisons are made.
Each paw/limb is measured as the dog moves over the mat. The imprints have colour variations related to the pressure exerted. For example red is high pressure.
If one paw then shows more intense coloration the ‘researcher’ can move to the tables to look for a change in stride in the opposite front or hind limb.
Looking at the row highlighted by orange and comparing the left front with the right front it can be seen that the left front stride length is repeatedly shorter than that of the right front. In dogs with a very subtle lameness this may be the only information that corroborates a client’s concerns about their dog. Looking at another column of the same individual (turquoise) we see that the force on the right hind limb is increased. This confirms that the dog is shifting its weight to the diagonally opposite limb.
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The acceleration, stride lengths, stance and swing phase times are measured. This information is then presented in graphs and in tables. There are tables that also compare symmetry between both front legs, left front and left hind etc.
In a clinical setting this equipment can assist with diagnosing a confounding lameness, as well as confirming a subtle lameness. It can also be used to establish the success of physical rehabilitation therapy. Measurements taken after a surgical procedure can be compared to those taken after a 6 week physiotherapy program. For canine athletes and working dogs a baseline reading can be taken. Regular measurements especially during times of intense training can assist with noting early signs of change and the training program can be adjusted so as to avoid serious injury or surgery.
The system has been validated in many research situations for both humans and animals. As pressure sensor walkways become more available more research will be conducted using them and more information will be accessible which will help veterinarians, and pet parents alike, to make sound decisions regarding the health of our beloved dogs.