I have an OTTB that was NQR. Lots of flexions, blocks, xrays, blood tests for Lyme and EPM, Osphos injections and Dr. Green later and still no diagnosis and no improvement. Put him on Estrone and consistant work and it went away. The first month or so if you saw me riding him he would be low grade lame. He needed to build up the muscling to support the stifle. We did not do small circles and we made sure what work he did was correct such as a marching walk, energetic trot, using his back.
During that first year if he went more than 2 day in a row without being ridden he came up stiff. So if he missed a 3-4 days due to an abscess or thrown shoe he came up lame. Now he is fit enough he can go a few days with no problems. He has also gotten into the habit of trotting around his field a few times randomly throughout the day so he keeps himself somewhat fit.
During those first few months I would not have taken him to a clinic or show but certainl would take him on a trail ride. Actually I would have been willing to take him to an obstacle course type clinic where you are primarily walking anyway. It was not obvious at the walk.
Years ago I was at a very small schooling show. There is a nice old white medium pony in the first division that is moderately lame.
First division is Leadline- so w/t, w/t off lead with handler next to them. Pony doesn’t need to do more than a little shuffle trot and is safe for kiddo.
Next division is shortest stirrup. w/t, w/tc, 4 itty bitty crossrails barely bigger than a ground pole. Pony is very safe and solid for a tiny tater tot of a child. Pony is not getting worse or better regarding lameness.
Next division short stirrup. Pony come into that division with the 3rd kid of the day. Judge halts the class, calls over the show manager and tells them to “Get that f*ing lame pony out of my ring and don’t let me see it again my classes.” Go judge.