Lameness Locator®: Frequently Asked Questions

Lameness Locator provides the veterinarian with an objective assessment of a horse’s movement. Subtle changes in symmetry of movement can be missed due to the limited temporal resolution of the human eye. Multiple limb or compensatory lameness can further complicate what we see. Lameness Locator inertial sensors sample 10x faster than the human eye, allowing for detection of very subtle differences in symmetry between the right and left sides of the body. Objective quantification of improvement can be obtained while blocking horses with diagnostic analgesia, allowing the veterinarian to better assess whether the lameness has been localized. Sequential evaluations also provide objective information on response to therapies, or improvement of an injury during a rehabilitation process.

The analysis informs the veterinary user of asymmetries in vertical torso accelerations between right and left strides. It provides a measure of amplitude of lameness, which limb is the cause of the asymmetry, i.e. which limb is involved in the lameness, and lastly, when peak pain is occurring during the stride cycle, i.e. is it a lameness that is primarily “felt” by the horse at impact, mid-stance or push off. The analysis is supplied in a single page report, providing an overall qualitative assessment in a graphical ray diagram, as well as individual calculations of asymmetry variables in both the fore and hind limbs.

The sensors weigh less than 30 grams each, and are inconsequential to the horse’s movement. The horse can be instrumented prior to the start of an evaluation and the veterinarian is free to proceed with his or her exam as they normally would. With practice navigating through the software interface, data can be collected and analyzed without impeding the normal lameness evaluation.

No technology currently available can determine where within the limb the pain is coming from. However, it can tell you if the peak pain is occurring at impact or push off, which may be useful in some instances – as certain pathologies tend to be impact lamenesses and others tend to be push off lamenesses. Further research in this area is necessary.

Data is collected instanteneously, i.e. in real time.

Data is analyzed immediately after collection. Analysis time ranges from a few seconds to about 15 seconds depending on the number of strides collected.

Yes, with a few caveats.

1. Many horses do not lunge well. Horses that do not lunge well or that misbehave excessively during the lunge will generate unreliable results
2. Thresholds for lameness on the Lameness Locator reports are determined for the straight line trot and should not be used to determine presence or absence of lameness during the lunge.
3. Lunging in one direction should not be analyzed alone. Instead, lunging in one direction should always be compared to lunging in the other direction. Lameness Locator software provides a dual reporting capability that is ideal for this comparison.
4. Many horses lunge with the torso tilted toward the center of the lunging circle. This results in expected head and pelvic vertical movement asymmetries. These expected asymmetries should be learned and recognized to assist in interpretation of the results.

Yes. However, it is best to compare results of flexion tests to results of a control trial, without flexion, with the horse trotting off in one direction for 8-10 strides. Use of thresholds and 95% confidence intervals determined by collection of at least 25 strides is not recommended.

Yes. The dual reporting capability of Lameness Locator software is ideal for this purpose. Significant positive results of blocking are indicated by a shifting of variable amplitudes from above to below threshold, or a shifting of variable amplitude outside the 95% confidence interval range (approximately 30% of A1/A2 values for LF and RF, 20% of A1/A2 values for LH and RH, +/- 6 mm for MAXDIFFHEAD and MINDIFFHEAD, and +/- 3 mm for MAXDIFFPELVIS and MINDIFFPELVIS).

All three sensors have a small strip of 3M dual lock tape fastened to one side, which lock into place to a second piece of dual lock tape on a specially designed head bumper, a pastern wrap for the right front limb, and directly to the pelvis. For added security in horses with long hair and for measurement of mild hind limb lameness, additional taping of the pelvic sensor to the horse’s pelvis is recommended. No clipping or glue is necessary.

With practice, about 3-5 minutes.

Very few horses have shown objection to any of the sensors. Occasionally, a horse objects to a head bumper. In these cases, the head sensor can be fastened to the halter.

Each trial performed is individually added to that horse’s database, so multiple evaluations can be performed together. For instance, you can collect data on one horse, and while waiting on a diagnostic block, you can collect data on another horse, then switch back and collect data on the first horse, without having to start a new “exam” for each one. To save additional time, many users prefer to have multiple sets of sensors.

Only one horse can be analyzed at a time. However, each Lameness Locator unit can be programmed to recognize several sets of sensors, such that different instrumented horses can be analyzed sequentially, without having to remove sensors from one horse to place on another.

In most cases data transmission will be 80-100 meters. In some environments transmission range will be up to 1/4 mile.

Thresholds between lameness and soundness and for determination of 95% confidence intervals were determined for collection of at least 25 strides. Therefore, it is recommended that at least 25 strides are collected for consistent analysis. However, it is not necessary to collect 25 contiguous strides. Trotting back and forth to get a total of 25 strides is all that is required, provided that obtaining at least 6 contiguous strides within each direction is achieved. Lameness Locator software will detect trotting strides and eliminate portions of the trial when the horse is not trotting, for example turning around when trotting back and forth.

1. For the straight line trot, an area that allows collection of about 6-8 contiguous strides each direction. Wireless transmission range of data is, on average, approximately100 meters.

The system will measure the lameness on the particular surface on which the horse is being evaluated – for instance some lameness is exacerbated in softer footing, some on hard footing. Surface characteristics will not effect the ability of Lameness Locator to measure lameness on a particular surface.

The system has been tested against the force plate and the camera and marker based system and found to be comparably repeatable and accurate.

Equinosis® has recently introduced its new robust Gen 2 sensors, which are water tight and fully rechargeable from zero volts. Sensors should last for two to three years with proper care.

If fully charged, about 3-4 hours. However, extended use can be achieved by short periods of recharging (5-10 minutes) between uses.

If fully charged about 3 hours.

The data collected and reports generated are automatically stored to the hard drive of the tablet. The reports generated can be saved as PDF files and copied into practice management software or printed out for clients.

Running the software to collect data and perform an analysis is quite easy and can be taught to a technician or assistant very rapidly. Understanding the analysis does take some training and commitment on the part of the veterinarian to appreciate the information the analysis is providing, to use the system most effectively. Years were spent developing the algorithms to analyze the raw data for the veterinarian and provide it in a manner as user friendly and intuitive as possible. A one to two hour initial webinar is performed with new users so that they understand the basics of the technology and theory behind it, and are comfortable in interpreting the analysis. Further training sessions via webinar can be performed depending upon individual needs as work with Lameness Locator progresses.

A one year software support and maintenance program is included with purchase of the system. This includes training and consultation as needed, technical support, and software upgrades. A fee based program is available to continue this program after year one. A one year hardware warranty is also included with the system.

The system is considerably less expensive than other diagnostic equipment such as ultrasound or radiography, and in most cases, can easily pay for itself in less than a year. Various purchase programs are available. Please contact 877-881-8002 for further information.