St Nicholas Abbey is recuperating in intensive care after undergoing complex surgery on a career-ending injury to a pastern.

The six-time Group One winner fractured a leg during a routine gallop at Aidan O'Brien's Ballydoyle stables on Tuesday morning in preparation for Saturday's King George VI And Queen Elizabeth Stakes.

St Nicholas Abbey underwent an operation on Wednesday, but still has "many bridges to cross before he is considered out of danger", according to Coolmore Stud, who represent the colt's owners.

"After a lengthy surgery to fuse the pastern St Nicholas Abbey is recuperating in intensive care at John Halley's Fethard Equine Hospital," Coolmore tweeted.

"St Nicholas Abbey will remain in intensive care for some time and has many bridges to cross before he is considered out of danger.

"This morning he is well and comfortable and back enjoying his hay.

"We are lucky he is so fit and has a marvellous attitude and temperament which will be vital for his long recovery."