It is not uncommon, where Lymes has been definitively identified, for a
horse to recontract the disease. The only recourse is to do the
tetracycline series again, perhaps adding an immune booster such as Eqstim.
We have a TB, age 20+, at the barn with stringhalt (stifle problem). The
vet has recommended the medial patellar procedure, but this involves
taking the old boy to a clinic since this must be done under general
anesthesia. However, the vet insured the owner there would be an immediate
improvement in his condition (it's pathetic to see him trying to get
around with his hind leg held high and to the side). The surgery itself
was too expensive, if I recall, but the clinic charges & anesthesia would
add up in a hurry.
I don't know if you had this procedure done, whether or not you could
continue with an active competitive career. We've only had contact with
older, arthritic horses and the procedure is done to provide relief
rather than extend a "career". Your vet can guide you best with this.
Your best bet may be to take your horse to Dr. Joyce Harmon or Dr. Judith
Shoemaker, both of whom do chiropractic/accupuncture, homeopathic work.
Your problem doesn't sound clear-cut. Who knows, maybe all he needs is rest.
Diane @ Safe Haven (I found my truck finally--buried under the snow)