Liu Xiang's surgeon, Nicholas Cullen, said he believes the injury was not as serious as feared, hinting the star hurdler might be able to resume training in six months.

The 29-year-old Chinese hurdler stunned the fans again as he crashed into the first barrier in the first round of the men's 110m hurdles and ended his third Olympic Games with a ruptured Achilles tendon.

He underwent surgery on Thursday at the Wellington Hospital in London. It is the largest independent hospital in the United Kingdom.

Cullen visited Liu in the Athletes Village on Tuesday night and made a preliminary assessment.

Liu seemed somewhat relieved and appeared to be in a good mood the next day. He sent a message to his father, Liu Xuegen.

"I had a very good sleep last night," the message read. "My doctor met me and confirmed the surgery last night. He will operate (Thursday).

"It's a small surgery and will not affect my life. Maybe I will be stronger after I come back. I treasure the hurdling event. I will be back. Since the hurdles are still there, I want to conquer them.

"The key is how I go about recovering after surgery. Just take it easy. Take care."

For the first time since the injury, Liu's parents were made available for a public interview on Wednesday.

His father said Liu's condition wasn't good when he arrived in London last Friday from Germany.

"I had phone calls with his coach after his arrival every day. It's like it would be a little better one day and then get even worse the next day," Liu Xuegen said.

His mother, Ji Fenhua, said she thought about asking Liu when he struck the barrier and hit the track in pain.

"I thought, OK, he could retire now …" she said. "But then we saw his message. He said he still wants to come back. We will not be against his returning after the recovery."

After arriving at the hospital at 11:25 am on Thursday, Liu went through a series of physical checks and was pushed into the operating room at 3 pm.

It was reported by qq.com that besides linking his tendon up, the doctor would also remove a calcified area left over from the last surgery.

Liu underwent his first surgery on the tendon at Memorial Hermann-Texas Medical Center in Houston in December 2008, four months after withdrawing from the Beijing Olympic Games.