Opinions please on back problems

[occasional_rider]

Hello I am hoping to leverage your expertise on the problems the horse I ride is facing. He had a terrible injury to his hind leg where he snapped a tendon (?) one that wasn't exactly required - possibly an extensor tendon? Anyway initial vet advice was that he'll never be sound again, second opinion was: see if he can learn to live with it, and given a year he was sound and back in work and completed 1 or 2 seasons of BE80 / BE90 level eventing and novice dressage, finishing Autumn 2014. Over the winter he got progressively stiffer and shorter, no obvious lameness but finally with reduced turnout he became so stiff to ride he eventually bucked me off. Saddle checked, teeth checked, no problems, occasional swelling in hind legs when he was in but nothing major, no obvious lameness. Physio was called and said his back was spasming and he was in so much pain they were surprised he hadn't become more dangerous. Cue months of long low work and ultrasound, which has made little difference - he is now intermittently still short and stiff. Next step is remedial shoeing to try and correct his gait (which given his injury is unsurprisingly altered) so that he can work his back muscles in a way that doesn't cause them to seize up.

My question is, how come he suddenly got so bad over the winter? He's about 11 or 12 so prime of his life. He wasn't doing much at all - hacking and schooling, minimal turnout - could it have been the reduced work that caused him to stiffen his back muscles? But if that was the case, how come reversing the work levels with careful schooling hasn't reversed the effect? Has anyone experienced anything similar?

 

[be positive]

I guess the reduced work/ limited turnout has caused something to happen in the area of the original injury that in turn has caused the back to tighten, the physio and new regime has done what it can for the back but without the damage in the lower limb being dealt with he will remain stiff, it is not as simple as reversing the work levels to fix something as complex as this, there may be some calcification around the tendon that is restricting his use of the limb or arthritic changes setting in in a joint and no amount of physio can fix that.

I think I would want to investigate a bit, scan and xray the area just to see what is really going on.