Ask the Vet: Poor Performance

Question: I have an 8-year-old Quarter horse gelding on trial. The pre-purchase vet check discovered a rounded coffin bone and the lameness test on the right front leg was as 1 on a scale of 5. The horse has been always been barefoot and is new to jumping. 

Answered by, Brian MacNamara, DVM, MRCVS, New Bolton Center, University of Pennsylvania, College of Veterinary Medicine Courtesy of AAEP

Would shoeing help his foot or is there a bigger problem on the horizon?  

Answer: Your question raises a few issues with regard to pre-purchase examinations and lameness evaluation.

First, I will assume that the “rounding” of the coffin bone (third phalanx) is present in the right forelimb, the one on which the horse exhibits lameness. Second, I am also assuming that “rounding” refers to some form of modelling of P3 that is significantly different from the left forelimb. Now, it needs to be determined if the changes in the right forelimb coffin bone are, in fact, the cause of the lameness. You didn’t mention if the horse responded to a hoof test examination, which might indicate if the foot is painful.

The general purpose of a pre-purchase examination is to determine the horse’s condition at that specific point in time. It is not meant to be diagnostic or predictive. In order to diagnose the cause of the lameness, further examination will be required: diagnostic nerve blocks, additional imaging (radiographs, ultrasound, MRI, scintigraphy, etc. ) may be required. Until an accurate diagnosis is made, it is impossible to give any meaningful advice as to the long term soundness of the horse. This can be an involved, and often frustrating, process that is well beyond the scope of a pre-purchase examination. Usually it becomes incumbent upon the seller and his or her veterinarian to diagnose the cause of the lameness. You can always go back and see the horse again in a few weeks after a diagnosis is obtained and whatever corrective measures are initiated.

 


My 10-year-old Quarter horse mare had a luxated or subluxated patella, which was put back by my veterinarian. She has been on stall rest for 3 months. She is using it a bit more although drags the leg from the side to underneath herself at times. Her leg is slightly turned out. Is there something more I could be doing for her? Exercises? 

Answer: It is likely that your horse has an upward fixation of the patella rather than a true luxation. If this occurred for the first time when she was ten, you should start with a detailed clinical workup to try and determine the cause. You say that she drags the leg, but it is unclear if she is lame. I would probably start with local anesthesia of all three joints associated with the stifle to see if that alters her gait. Radiographs and ultrasonography may be beneficial in determining if there is any injury to the patellar ligaments or the patella itself. If she is dragging the leg, I would also be concerned about possible meniscal or cruciate ligament damage in the stifle joint. Diagnostic imaging would be useful in assessing those structures as well. I would not recommend any treatment or exercise until a more accurate diagnosis is obtained.

In cases of idiopathic upward fixation of the patella, local injection around the medial and middle patellar ligaments sometimes is helpful. There are also several surgical procedures aimed at shortening the ligament (or cutting it) that may alleviate that condition. If there is meniscal, cruciate ligament or patellar injury, there may be either surgical or medical treatment options: arthroscopy, shock wave therapy, platelet rich plasma, other joint injections. Again, however, you must try to get a more definitive diagnosis first.