Abstract

Objective: To assess whether a rule change introduced in the Australian Football League (AFL) prior to the start of the 2005 season, to limit the run-up of ruckmen at the centre bounce, has been successful in reducing the incidence of knee posterior cruciate ligament (PCL) injuries.

Design: Cohort study with historical control.

Setting: The AFL competition from 1992 to 2008 inclusive.

Assessment of risk factors: The presence of a rule change (four seasons) compared with the previous 13 seasons (divided into two eras of seven and six seasons).

Main outcome measure: Occurrence of knee PCL injury during a regular season or finals match, both from all causes and specifically from centre bounce ruck collision mechanisms.

Results: From 1992-1998 there were 11.0 PCL injuries per 10000 player hours, with 0.8 ruck injuries per 10000 centre bounces. From 1999-2004, the rates increased to 12.9 per 10000 player hours and 5.6 ruck injuries per 10000 centre bounces (p<0.01). The rates reduced to 5.9 PCL injuries per 10000 player hours and 0.9 ruck injuries per 10000 centre bounces in the period 2005-2008 following the rule change (p<0.01). There was lower relative risk from 2005-2008 compared to 1998-2004 of incurring a centre bounce ruck PCL injury, 0.16 (0.04-0.69), or of sustaining any PCL injury, 0.45 (0.28-0.75).

Conclusion: Rule change in the AFL to limit the run up of ruckmen at the centre bounce has successfully reduced the rate of PCL injuries with this mechanism, with total incidence of PCL injuries also falling.