The British composer was expected to attend the celebrations in New York this weekend but had to pull out days before after his back troubles prevented him from travelling from the U.K.
Taking to Twitter.com on Saturday, he wrote, "Mortified my hospitalisation stops me from being at Phantoms (sic) record breaking Broadway night. Thanks to everyone who made it happen."
He has since had the operation and is now recuperating at home.
Updating fans about his condition, he writes, "Thanks to everyone for all your kind words on Phantom25BWay. I'm out of hospital, feeling rather sore, but at least the worst is over."
Lloyd Webber has been in and out of hospital in recent years - the 64 year old underwent hip replacement surgery in late 2011 and previously overcame a battle with prostate cancer.