David Parker, 38, told police that Spence, who disappeared in April 2011, was held at his flat in West Kilbride, Ayrshire, after he was offered £1,500.
At the flat, she was burned with a steam iron and hit with a golf club while bound to a chair and wearing glasses with black tape on them, the High Court in Glasgow heard.
A taped police interview was played to the jury in which Parker told officers he was on medication for post-traumatic stress disorder.
He denies any involvement in Ms Spence’s murder.
He was asked during the interview: “Her kneecaps were broken, weren’t they?”
Parker replied: “Yes. I remember my golf club was missing.”
Asked on tape again later about his comments on the alleged kneecapping, he said that he had said it was her “legs” that had been hit.
He added: “When I went up to give her a cigarette or a cuppa I noticed my golf club was all twisted to bits.”
The club was a seven iron, he said, which he had found and had used to try to teach his son to play.
He told police he did not know who had used the club on Ms Spence.
Parker is one of four men accused of the 27-year-old’s murder.
Colin Coats, 42, Philip Wade, 42, and Paul Smith, 47, are also on trial for abducting, torturing and killing Ms Spence, which they deny.
They are accused of holding her hostage for up to a fortnight and assaulting her in an apparent bid to extract financial information from her.
Parker said he agreed to allow his Meadowfoot Road flat to be used after being approached by Smith.
He told police in the interview on October 31 2011: “This has given me post-traumatic stress disorder.
“I’m on medication, I’m seeing a psychiatrist after this.”
The trial before Lord Pentland continues.