We examined the area, felt it, worked him and watched Kat go around and around both directions on the lunge line at the walk, trot and canter. Again, no heat, no swelling, no signs of soreness, no lameness, nope, nadda, nothing and a lot of WTH?
I have always been super careful of the lower legs because of everything in the big barns with the halter trainers. Super. careful. All. the. time. I am now looking into whether or not splints in driving horses are more common. When you consider the work load- it could be a likely possibility. *I will elaborate more on this in another post.*
Bottom line- Kat did pop the splint. It happens. It is a hard little knot about the size of a pea, only slightly noticeable when looking at him from the front, but still there. You can feel it when you run your hand down his leg, which is how I found it to begin with. The only way he could have done it was to injur himself somehow in the stall. Otherwise, he did not have it the last time I had worked him or I would have felt it while running my hand down his leg after removing his boot or polo wrap. How it got hard so quick? It could have been a 'blind splint' for a while, just not causing him any pain, or presenting any heat and associated inflamation.
From another article I found on The Horse dot com, Recurring Splints, What's a Splint and Young horses in training and injury risks (these articles come up in full to read), it seems the lower injury is more common in older horses than the splint occurring higher up, like Kat's. From past experience of treating the splint on the young filly, sweating it out, blistering and a few other treatments are common, but mostly all of them recommend time off to rest and heal. I may wrap his leg to sweat it some and try to reduce the size of the splint, but I am not a fan of blistering, pin firing or any of the other stuff. Why cause pain on the outside to treat the inside, then give them the recommended rest anyways? It doesn't make sense to me.
Where Kat is not presenting any pain or soreness, I can keep working him, but I will be keeping a close eye on him, his movement and will stop immediately if he is hurting. "No pain, no gain" can take a flying leap off a short cliff here.