Springbok captain Joost van der Westhuizen has been dealt another serious injury blow as a knee injury has ruled him out of rugby for six months.

The Bok skipper, who valiantly led his side to third place in the World Cup, arrived home on Tuesday to discover that he had again torn knee ligaments and would, once again, miss out on the majority of the Super 12.

Van der Westhuizen apparently tore the ligaments in the World Cup semifinal against Australia at Twickenham over two weeks ago and played through the pain in the third-place playoff victory over New Zealand in Cardiff last Thursday.

This is the third consecutive time that Van der Westhuizen has returned from a tour to the British Isles with a serious injury. In 1997, he tore groin ligaments and was out for six months. Last year he was stretchered off against England with torn knee ligaments and again spent six months on the sidelines.

Van der Westhuizen returned home to a heroes' welcome at Johannesburg International airport on Tuesday. Thereafter, he saw Pretoria knee specialist Dr Daan du Plessis, who diagnosed that the knee ligaments were torn again.

Speaking from his home last night, Van der Westhuizen expressed disappointment at yet another end-of-season injury.

"I thought I tore it against Australia. There was a lot of discomfort, but I decided to play the full game against New Zealand. I'm obviously very disappointed at the result of this, but what can I do," Van der Westhuizen said.

"Still, I hope to be back on the field by the end of April and to help the Northern Bulls out once again in the latter part of their Super 12 campaign."

Van der Westhuizen will be operated on in a Pretoria clinic this morning. He will rest for at least two months before beginning a long and arduous rehabilitation programme.

Bok coach Nick Mallett was as devastated as Van der Westhuizen by the news.

"It's a terrible blow for us, but Joost is a fighter and I look forward to seeing him back on the field next season, hungry as ever," Mallett said on Tuesday.

Bok physiotherapist Wayne Diesel said last night that there was no indication during the tournament that Van der Westhuizen was not fit enough to play.

"We evaluated Joost before the tournament and his knee was stable enough to play. Throughout the tournament his knee was also taped and strapped and at no stage was it swollen or did it jeopardise his position," Diesel said.

"We recommended that when we got back he have it re-evaluated and Dr Du Plessis felt that there was no need for a scan and that the operation was necessary."

At a press conference on his return, Van der Westhuizen claimed he had been the target of a personal vendetta. A Sunday newspaper reported that senior Boks were unhappy with his style of captaincy and tendency to only look out for himself.

Van der Westhuizen said, however, his players would confirm that they had no problems with him or his leadership.

"Some of them are here. Speak to them for yourselves and you will hear their reaction. This was the work of one newspaper," he said.

Mallett also supported Van der Westhuizen on Tuesday. "He had an outstanding World Cup both as a player and as a captain. He was voted clearly the best scrumhalf at the tournament and he led by example."

Lions No 8 Andre Vos said: "It's news to me that there was unhappiness in the team over Joost. The spirit was good at all times and we came so close to making the final ourselves. People sometimes say things because of disappointment when in fact they are not always true."

Apart from Van der Westhuizen, the knee of another Bok, Bob Skinstad, will be of concern to Mallett. A probe will be done on his dodgy knee on Thursday.