Not All Splints Are Created Equal!!

The radiographs below are from the forelimbs of a lame horse. The horse had prominent "bumps" on the inside of both canon bones and only one was sensitive to direct pressure (right front). These bumps were consistent with osseous or bony callous formation over the splint bones which are also know as "splints". The  splints had been present for over 45 days and despite moderate rest, the horse remained lame. Specifically, the horse was lame in the right front limb when trotted in a circle to the left! Careful exam of these "splints" revealed that in addition to being painful to pressure over the callous, the horse was positive to pressure over the suspensory ligament at the level of the fractured splint.

Ultrasound exam of the soft tissue structures near the fractured splint revealed an inflamed suspensory ligament. The image below highlights the suspensory ligament (yellow arrow). The areas of black are consistent with edema/fluid accumulation within the ligament and are adjacent to the bony callous. In addition  to the presence of edema/fluid, the fiber pattern is irregular. These findings are consistent with moderate inflammation of the suspensory ligament, most likely due to physical interference via the bony callous. 

The ultrasound image below compares the left and right suspensory ligaments at the level of the corresponding "splints". A clear difference can be seen between the suspensory ligaments (area under the yellow curves) of the lame leg (RF) versus the non-lame leg.

The horse was scheduled for surgery and the offending splint bone was removed. At the time of surgery, moderate inflammation of the suspensory ligament was confirmed. The gelding underwent an extensive period of rehabilitation consisting of rest and controlled exercise. Three months post surgery the gelding is back to work and completely sound. Special thanks to Dr. Tim Lynch at Peterson and Smith Equine Hospital for his surgical expertise and great collaborative effort!

This case is not unique and reminds us that we should pay close attention to ANY "splint" development. Most often, splints resolve without the development of lameness or significant complications however if the appropriate care is not considered, the likelihood of complications does increase. Appropriate care includes forced rest, ice therapy, topical Surpass, and shockwave treatment.