THE RECURRENCE rate of serious knee injuries has emerged as a key area of concern for the AFL and its medical experts.

The 2013 injury report, which was released on Tuesday afternoon, showed there were 23 knee reconstructions performed on AFL players last year, up from 16 in 2012 and 20 in 2011.

Click here to read the full 2013 AFL Injury Report (pdf)

Eight of the injuries suffered in 2013 were cases in which players needed a second reconstruction after their initial graft failed. In three of those cases, a LARS graft had been used.

Sparking concern is the fact that no more than four players experienced the failure of a knee ligament graft in one year during the previous decade.

According to the injury report, the number of repeat knee injuries recorded in 2013 "represents a high failure rate, which warrants further analysis".

The injury report was written by Associate Professor John Orchard from the University of Sydney, Dr Hugh Seward of the AFL Doctors' Association and Jessica Orchard from the University of Sydney.

The authors found that hamstring strains remain the most prevalent injuries in the competition, and they drew attention to the fact that the number of hamstring and groin injuries has fallen since the introduction of the substitute rule in 2011.

But they also found that "calf, knee tendon and other leg/foot/ankle injury incidence and prevalence were significantly higher in the period 2011-13 compared to 2008-10.

"It is possible … that AFL clubs have successfully implemented prevention regimes for the most common injuries, but have not devoted as much specific preventive work towards less common injuries.
 
"It is also worth noting that the recurrence rate for hamstring injuries in 2013 was, at 24 per cent, higher than recent years, but still well below the recurrence rates seen in the 1990s."

The report notes that overall injury rates have risen as the number of interchanges per match has increased.

When it comes to head injuries, the number of games missed by players due to concussion has risen markedly in recent years.

But this is attributed to clubs treating concussion as a more serious injury than in the past.

"Concussion has been a major injury concern for all sports in recent years, with further understanding that there is a possible link between concussions suffered in sport and neurodegenerative conditions in later life," John Orchard said. 

"Reflecting these concerns, the AFL and AFLDA introduced revised concussion management guidelines at the beginning of the 2011 and 2013 seasons that reinforced a more conservative approach to concussion management."

The advisory panel that also had input into the report was made up of Dr Andrew Daff, who is a medical officer with the AFL Players' Association, Richmond club doctor Greg Hickey, Hawthorn club doctor Michael Makdissi, Adelaide club doctor Andrew Potter and Sydney Swans physio Matt Cameron.