personnally, though he may be sound for it now, i would NEVER jump a horse trhat had had knee surgery of any type. a bone chip is a BONY CHANGE, that if not cared for properly can turn to painful debilitating artheritis in the future. flat work, great, not mountain climbing or expcting his previously injured knee to support the impact of roughly 400 lbs. (30%) of his body weight coming down on it on a regular basis......if you trained him as a jumper hed be sold as one and used for it again and again and again.....is it fair? not thatt im right by any means just some thoughts.