“For the two years before I had the operation I couldn’t extend my leg properly, so my right leg would always bend when I went to extend it and that was affecting my serve a lot,” he said.
“But now, because it does extend properly, I am able to serve well again and am able to serve as hard as I was in my mid-20s, which given I didn’t know I was going to be able to play again has been really positive.
“Obviously when you are able to serve bigger and harder, it means more shorter points – and that means good news for the body and the hip.
“The harder I serve, the better it is for my other hip I guess.”
Sue Barker: Our Wimbledon will be broadcast live on BBC One on Saturday July 4 at 3.15pm.