I sympathise as my youngster has just been diagonosed with chronic sacroiliac problems in her off side hind so pretty gutted about that. Old injury from before i had her the vet things...
I would have agreed till recently that there are pro's and con's with wood v plastic however with the amount of rain we have been having recently, I took the plunge and bought some wood-filled plastic jumps from Jumpsonline. They are much better priced than Jump4Joy and the poles are woodfilled...