The ACL curse

The 2015 season has already been marred by a spate of ACL injuries.

This blog is going to discuss the ACL injury, why it occurs in AFL and why we think it has a higher incidence at certain times of the year.

Australian Rules Football (AFL) is known for its high level of physical body contact. These high impact collisions can occur from any direction. Players typically wear no protective padding of any kind except for a mouth guard. As such, impact injury rates tend to be high.

Full contact play with the potential to be tackled or bumped from any angle means that the risk of a knee being twisted or caught on a dangerous angle is high. Injuries to the knee, ankle and shoulder joints are common.

Knee reconstructions (especially from ACL injury) are among the season or career threatening injuries. 

The 2013 AFL season could legitimately be renamed the "Battle of Wounded Knee".

The 2013 injury report, showed there were 23 knee reconstructions performed on AFL in 2013, up from 16 in 2012 and 20 in 2011.

 The rate of ACL injury in 2013 was far higher in pre-season and early rounds, compared to the winter months, while northern AFL teams tend to have slightly higher rates of ACL injury than southern AFL teams.

The following injury statistics have been drawn from the AFL 2013 season injury report.

The report stated that there were increases in overall injury incidence, prevalence and recurrence rates for the 2013 season, but no significant statistical change in the three year-period 2011-2013, compared to the previous three-year period covering 2008-10. There was a statistically-significant increase in both injury incidence and prevalence over the years 2008-2013 (“High interchange era”) compared to the years 2002-2007 (“Low interchange era”).

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

Associate Professor Tony Blazevich, a sport science expert based at Perth's Edith Cowan University, says while the AFL continues to try and tweak their game to minimise the risk of high contact, most ACL injuries occur without any impact at all.

"About 75 per cent occur when there's no contact at all. The ACL is typically injured when a player rapidly changes direction, but it also occurs frequently during one-legged landings after jumping," Professor Blazevich said. "These injuries mostly occur when the knee is loaded whilst straight, when it twists during landing, or when the knee wants to collapse inward. "So preventing these movements is the key to reducing ACL injury and it can be done reasonably effectively with physical preparation and player monitoring."

While no singular reason for this year's rush of ACL injuries can be pinpointed, research over almost two decades has found several predisposing factors for the AFL star's worst nightmare.

Key Points:
* Most ACL injuries occur without any impact

* Fatigue and sudden changes of direction increase risk of ACL injuries significantly

* Better quality boots causing more traction

* ACL incidence is highest during pre-season and start of the season because:

-          Firmer grounds early in the season compared to mid-late season

-          Faster game therefore change of direction of higher speeds and also higher   incidence of fatigue

-          Players have bigger upper bodies, therefore causing more torque on lower limb when changing direction. Players “thin out” as the season progress

Researchers believe the more fatigued a player is, the more likely he is to do his knee. Making a last-second decision to change direction also increases the injury risk significantly, while playing on high friction grounds elevates the odds of a season-ending incident.

Unfortunately for some, the body might also be just as responsible for the injury as the footballing fates.

Those with a shallower inter-condylar notch - the groove into which a thigh bone sits in the knee - are now known to have a higher chance of ACL troubles. And women are more likely to rupture an ACL when playing the same sports as men, partly because oestrogen increases ligament laxity.

"One study found that 50 per cent of soccer players with ACL injury developed osteoarthritis within 12 years," Professor Blazevich said. "Given this, a significant effort should be given to reducing the risk of ACL injury."

Walker, Morabito, Suckling, Patton, Schoenmakers, Smith, Menzel amongst others would surely agree.

 

Josh Banky is a Physiotherapist. He works at Lifecare Prahran Sports Medicine on Monday, Tuesday Wednesday and Friday. The clinic is close to suburbs including Malvern, South Yarra, Richmond, Caulfield and Hawthorn, and has early and late appointments for all your Sports Medicine and Sports Physiotherapy needs.  You can find more on Josh on our practitioners page.