ALEX Johnson's fourth knee reconstruction is likely to cost him the 2015 season and possibly his career, says leading sports medico Dr Peter Larkins.
 
The luckless Sydney Swans defender needs another reconstruction after persistent infection forced the removal of his latest LARS graft this week.
 
The 22-year-old had the artificial ligament put into his knee in July this year but has been plagued by infection throughout the recovery of all his operations.  
 
Larkins said the fact the four-month wait between the failure of his second graft and his third reconstruction didn't discourage the infection, it was likely his upcoming operation would be put off until next year.
 
"There's no time frame you can put on it because they thought four months was long enough," Larkins told AFL.com.au.
 
"My personal opinion is that they won't do less time this time, it will be at least the same amount of time if not longer, so I don't expect it to happen in 2014.
 
"My sense is he won't play footy in 2015 either."
 
Johnson had his first reconstruction in early 2013, followed by two LARS procedures.
 
All were affected by the infection, which has led to the removal of the latest graft.
 
Larkins explained the infection was caused by a normally harmless bug.  
 
It was treated with antibiotics before his last reconstruction and was thought to have been resolved, only for it to flare again six weeks into his recovery.
 
"It was a skin infection – a bug that normally lives on the skin that got into the knee," he said.
 
"It's a bug that sometimes doesn't create problems – we've all got it on our skin, it's a natural bug everyone's got and not normally a dangerous one."
 
Larkins said it was likely Johnson would undergo a conventional reconstruction this time after the failure of two LARS grafts.
 
But he said the Swan's career was in doubt after the latest setback.
 
"I think it doesn't bode well for the future, because having had three reconstructions it means that the hole inside the knee isn't normal anymore, particularly the tunnels that are in the bone," he said.
 
"There will be a need to think very clearly about what options he's got.
 
"His knee is always going to have some residual deficit in strength and support, no matter what operation he has for No.4."
 
Still, Johnson has set his sights on playing again and doesn't want his career to end on his last AFL game - the 2012 Grand Final.  
 
"It is obviously very frustrating but I have no choice but to attack the situation with a positive attitude," Johnson told the Swans' website.
 
"It has been a difficult couple of years but I love football and while I understand the challenge ahead, I am determined to get back out playing."
 
It is not known when he will have the next bout of surgery, or how long the recovery will take.
 
However, the 45-game player continues to remain upbeat despite the latest setback.
 
"Alex has had the most unfortunate time with injuries over the last two years, but his positive attitude throughout has been really remarkable," Swans football manager Dean Moore said.
 
"Naturally, he is disappointed about the latest setback but is determined to do everything he can to return to the field and we will support him as best we can.
 
"He is an incredibly strong young man and I have little doubt his positive mindset and determination will see him overcome what is a significant challenge."