Could this be the cause??

[minmax]

My 4 yr old is going for an arthroscopy next week re OCD. I am wondering if the problem may be due to very deep mud from when he was 2. He was moved from the field he had been in to a small paddock up away from where he had been. This sent him nutty, so he started fence walking that if left too long would be fence galloping! I would turn him out for a while but something would set him off and he would go up and down the fence. He was fine for a certain amount of time though??
He developed Lymphangitis and had to stay in for a while, this seemed to help the legs but then he had to go back out in the field. Eventually I managed to get the YO to allow me to move paddocks. He was a lot better nearer the yard.
I am wondering if the joints have been pulled apart in the mud????
His xrays from 6 mths ago and last week are the same, no changes.....

 

[Box_Of_Frogs]

Is he a TB? Friend at my yard has a TB and he seems to have a serious death wish - forever injuring himself. So owner didn't want him in the big herd in case he managed to injure himself again. But he had other ideas and was desperate to be with the "gang" rather than the couple of neds he was in with. He fence walked, fence trotted, fence cantered all day every day. When he wasn't fence walking he was pressed right into the corner of the hedge/fencing where, if he strained his neck really hard, he could see the gang. So sad, poor lad. He would come in dripping in sweat and miserable. Having seen what desperation can do to a TB, I'd agree that your 4yr old could easily have caused himself a strain or scratch that could have led to the lymphangitis. I don't think he will have pulled the joint apart in the mud, just the desperate repetitive action may have given him a sort of equine RSI. I'm surprised you kept him in with lymphangitis as moving around is much better for filled legs. If he gets so stressy and unhappy at the t/o rules on your yard, he might be happpier somewhere else.