Nicky Henderson has revealed Shishkin has been found to be suffering from a “pretty rare bone condition” following his disappointing performance in the Queen Mother Champion Chase at Cheltenham.

Unbeaten in seven previous starts over fences, the eight-year-old was a hot favourite to claim a third Festival victory in last month’s day two feature.

But the writing was on the wall for his supporters from an early stage, with Nico de Boinville giving up the ghost and pulling up Shishkin in the back straight.

Henderson was initially minded to blame the testing conditions following torrential rain in the Cotswolds, but has now discovered another reason why his stable star did not run up to expectations.

“Immediately the next day he was actually perfectly alright, then he was lame for a couple of days and then he was sound,” the Seven Barrows handler told Unibet.

“We weren’t quite sure where he was. Initially we put it down to the ground, but I think in out heart of hearts we knew that even though it was atrocious ground, that that wasn’t the whole thing – there was something else that was bugging us.

“We have, to say the least, dug and dug and dug until we could come up with something. There was nothing obvious, but he was intermittently lame on different legs, which seemed rather strange.

“We recently did a bone scan on his whole body and that would normally show you the one hotspot and tell you where the lameness is. On this, four different hotspots came up in completely different places.

“He has what you would have to call a pretty rare bone condition. Why on earth he should all of a sudden do this on the day of the Champion Chase, goodness only knows, but that’s the first day it affected him – he’d never taken a lame step the whole way through his preparation.

“The ground we knew was a concern, but that’s got nothing to do with it.”

The curious problem means plans to run Shishkin in the Celebration Chase at Sandown have been shelved, but Henderson sees no reason why he will not return as good as ever next term.

He added: “It is a very strange problem, but it’s something that’s very mendable. He’s going to have a month’s box rest, then a month’s walking and then we’ll turn him out in the field.

“There is absolutely no reason why he won’t be ready for the beginning of next season. Once the bone has stopped this development in these four identifiable areas, that’ll be the end of it.

“Sadly all it means really is he’s going to miss the Celebration Chase at Sandown, which is where I’d hoped he would go.

“It’s a pity he won’t be able to run there, but as long as he’s alright for next season, that’s all that matters.”