Mild lameness conditions: Sometimes horses have lameness that, although it is of mild severity, is significant enough to adversely affect performance. Such lameness may be difficult to “see” during a standard, subjective lameness examination. Computer-assisted lameness evaluation is very sensitive at “picking up” these lameness conditions. Computer-assisted lameness evaluation may also be beneficial at differentiating horses sound horses with training problems affecting performance from horses with mild lameness affecting performance.

  Multiple limb lameness: It is very difficult in horses with multiple limb lameness to accurately determine the most important or primary source of lameness. From what we have learned about compensatory lameness in the horse and the ability of computer-assisted lameness evaluation to quantify lameness in each limb we have found it very useful at separating out multiple-limb lameness conditions.

  Foxtrotters: There are 3 reasons that lameness in Missouri Foxtrotters is more difficult to diagnose accurately.

 i. The head movement is normally exaggerated compared to other breeds of horses. This exaggerated head movement has a tendency to “throw off” or “confuse” the evaluator, especially if he/she is using the asymmetrical nature of vertical head movement. Thus, small changes in the symmetry of head movement may be missed. Computer-assisted lameness analysis allows detection of small changes in head movement asymmetry.

 ii. Vertical pelvic movement is depressed. Because of this foxtrotters are good at “hiding” hind limb lameness. Computer-assisted lameness analysis is more sensitive to the naked eye at picking up small asymmetries in the movement of the pelvis that signify hind limb lameness

 iii. When foxtrotters are lame they start pacing at normal speeds. Use of the treadmill allows the evaluator to change speeds until the horse is forced to trot. This may not be possible or at least may be very difficult trying to do this by running next to the horse with a lead shank.

  Shifting limb lameness: With mild lameness or lameness that is difficult to see the evaluator frequently studies the movement of the horse until he/she recognizes an clear abnormal or lame stride. He/she then has the tendency to “lock in” their evaluation to a specific limb. However, we have noticed that, for some lameness conditions that tend to have a bilateral nature (a good example is navicular disease and degenerative joint disease of the distal tarsal joints [i.e. spavin]), the lameness will frequently shift back and forth in one sequence of contiguous strides. Therefore, make a snap judgment based on 1 or 2 strides may be incorrect. Computer-assisted lameness analysis on the high speed treadmill, because it analyzes the lameness on a continuous, stride-by-stride basis is able to pick up and characterize the tendency to shift sides. In one sequence of 30 strides, we may be able to, for instance, see that the horse took 10 strides off in the right forelimb, followed by 10 sound strides, followed by 10 strides off in the left forelimb.

Rapidly changing lameness: Computer-assisted evaluation of lameness on the treadmill has allowed us to document objectively if a lameness is going away as the horse warms up with increased exercise or if the lameness gets worse with exercise. This is very helpful, especially when we are trying to evaluate the change in lameness after a local or regional nerve block performed in an attempt to isolate the lameness.