Likewise he has shown no lameness with a fractures splint bone with bone chips.. Funny old horse 
Are there any people who are 100% sound?
As they say, life is a chronic condition.
I do think "functional" is a different deal, as many horses have weaknesses and injuries that don't interfere with their ability to keep doing their jobs, sometimes into very old age. There are too many variables - is a horse that stays sound if it doesn't jump more than 3' with good management?
Some horses just seem to have high pain tolerance and a mental make up that keeps them working even with issues. Others are just very well built so even when they do have a problem, the rest of them is strong enough to compensate for a weakness. I also don't think the sort of management people sometimes think *should* work, is what actually does. The soundest horse I've had raced at two and literally never had any significant time off until he was put down at 28 last summer. He technically had a spavin from racing and did have a check ligament injury, which healed unnaturally quickly so was he just a naturally tough horse? He was also medium sized, athletic and had good conformation - all bonuses. The one I have now is "hard luck" and gets everything going but is also huge, from a line of very sensitive horses, and not naturally careful.
Also - and this might be contentious - I do think perhaps we put a lot of emphasis on treating/fixing conditions now, whereas when treatment options were more limited, good horsemen took more care to prevent problems. (And, tbf, there were a lot more lame horses about!!)
And, like with people, horses live a lot longer now and are more likely to "survive" even quite serious issues. To be blunt, where I grew up, if they stopped working they rarely continued living.
One area that's really interested me is shoeing. I seen a fair number of horses with not particularly good shoeing jobs (sometimes just poor, but other times very odd aggressive) who eventually go lame . . . are they intrinsically unsound horses? Others have aggressive treatment for one thing which leads to a problem somewhere else . . . again, inherently unsound or victims of circumstances? There are legions of similar influences, from footing to riding practices.
Also, we have so many more diagnostic options available now and vets are hardwired to keep looking until they find something. I suspect some horses that come right with significant vet intervention might also have come right with a year off, with no one any the wiser to the specifics of the problem. (I'm not saying lame/ill horses should be turned away or that intervention isn't a good idea, just that when it was more common practice to wait and see, a surprising number of horses DID come right.)
I think it is often very possible to make horses functional and comfortable to work without necessarily curing, or even covering up, what ails them.
Sorry, my specialist subject, "underperforming" horses!
I don't think internet forums are a good sample thought - it's mostly people talking about problems!
after having 15 years with him. He was brilliant or awful with very little in between but super talented and super sound 
However I wanted something to point to point, and he was galloping and jumping around the field like a loony all day long.
Thank you. Your response has helped me more than you could know
I do think that distinction has been lost a bit but it was quite important way back when.
though she did love him! (the foal was totally unplanned & her idea).
Oooh, now I'm curious. . . .
To add, in my dim and distant youth, I remember the Manual of Horsemanship made a distinction between "unsound" and "lame". An unsound horse was one with a problem, such as a noticeable spavin, an old bow or a significant conformation fault, a lame horse was one that was, well, lame.
Because you made me realise that it maybe possible to manage a condition and still do the things I want to do.
That sometimes just because they have 'x' doesn't mean they are a right off
I have RA and I manage it and still mostly do what I want to do, maybe not when I want but hey and you made me realise the same can be done with horses I hadn't ever really thought of that, I had just thought if it comes back Micah has KS or whatever that it would either be fixed or it wouldn't, not that I could perhaps 'manage it'
My horse with the hock spavin never had a lame day on it and never had it treated (even under heavy sedation that would have been suicidal for the vet and because he was never lame, it never seemed worth the risk) although he did drag his toe a bit before he warmed up when he was in his teens so he retired to a dressage career. Eventually his flying changes came apart a bit so he dropped down a level with a less experienced rider but again, never actually took a lame step. Lame or sound?
Oh, well done, me, then.
A succinct appraisal of the situation (succinct isn't really my strong suit!).
It seems to be a bit of a "dirty little secret" how managed top competition horses are. There was a horse on Canada's bronze medal dressage team in Seoul with spavins so large you could literally see them from 10' away. Lots of event horses have to be virtually wheeled out of their stables in the morning before they loosen up. I know jumpers with all sorts of things injected regularly. I realise it's not idea but don't make the mistake of thinking all those horses are "perfect". I would hazard a guess there are lots of horses doing quite high level competition that aren't in any way "100% sound".
On a less famous level I know all sorts of horses with quite serious problems still doing their jobs. A student of mine had a horse with diagnosed kissing spines that jumped for 5 years after the diagnosis. I had a horse diagnosed with navicular at 5 who primarily evented and was ridden well into his 20s.
I think I've mentioned before that I used to run a riding school staffed almost entirely by ex-show horses and/or horses inherited from a very intensive eventing educational institution. We did all sorts to keep them up and running but they were all functional, happy horses, many well into their 20s. Most jumped almost every day - always on good footing, not too big and WELL within what they were capable of - and worked 6 days a week, often doing one "easy" and one "hard" lesson. We also had a number of "lease" horses that were there primarily because they wouldn't vet but were all regularly leased out to show with riders who had graduated from the school.
As to all the horses that never took a lame step, the flip side is, because of that, no one ever investigated either. Perhaps if you'd stuck them in a MRI machine they would have lit up like Christmas trees?
A surprising number of horses can be kept functional with just changes in routine, at least initially. I'm not in the habit of discussing business on the internet but I do have a horse on my slate right now that looked at least that bad a few months ago and is now apparently the soundest he's ever been, with ONLY changes to his management and riding. I have no doubt he'll need more help in the future but right now he continues to improve so we'll stick with the program.
All I'm saying, is don't assume a worrying diagnosis is necessarily a disaster. I do try not to be the patron saint of lost causes, but there are lots of things you can do to improve situations you won't ever be able to cure.
thanks