Damage to the anterior cruciate ligament, the ACL, is a common injury in sports that require frequent high speed changes of direction or twisting of the knee joint, such as in football, netball, and skiing. David Schwarz, Liz Ellis, Anthony Koutoufides, Alisa Camplin and Luke Darcy, to name a few elite athletes, have all experienced the devastation of an ACL injury. It is often an extremely painful injury that can keep an athlete out of competition for up to a year. In Australian Rules football, ACL injury is responsible for more than 10% of lost player time.

The ACL is one of four major knee ligaments, a strong rope-like tissue joining the thigh bone to the shin bone. The ACL is located between these two bones in the middle of the joint, helping to reinforce and stabilise the knee. The ACL and the posterior cruciate ligament or PCL cross in the centre of the knee joint. Their function is to maintain the position of the shin bone under the thigh bone. The ACL is most often damaged by a non-contact mechanism where the athlete’s leg is almost fully extended at foot strike. The ACL can also be damaged through contact forcing the athlete into a knock-knee position.

An ACL injury can be devastating for athletes. After tearing his ACL in the lead up to the 1995 AFL season, Melbourne player David Schwarz underwent a knee reconstruction, returning to play only two games before again injuring the same knee, requiring a second reconstruction. The next year, Schwarz again injured the same ACL requiring a third knee reconstruction. It is highly likely that Schwarz’ re-injuries resulted from returning to competition too early. Research conducted by sports physician and sports injury researcher Dr. John Orchard reports that a player is almost ten times more likely to reinjure their ACL in the first 12 months after the initial injury. After his third knee surgery Schwarz returned to football after 18 months of rehabilitation. He won his clubs best and fairest award in 1999 and went on play many more years of football, retiring in 2002.

Hopes of captaining the Australian team in the 2006 Melbourne Commonwealth Games were destroyed for Liz Ellis when she tore her ACL and damaged her medial collateral ligament (MCL) in 2005. It was her first major injury in many years of playing netball. Ellis underwent reconstructive surgery and has since returned to elite netball without re-injury.

Unlike netball, in football, the risk of ACL injury is affected by both the climate and type of grass. Wet conditions and a ryegrass playing surface reduce traction between football boots and the ground surface, reducing the risk of ACL injury according to Dr. Orchard.

The ACL can be damaged through a tear, or it can be completely torn from the bone. Damage to the ACL is often in conjunction with bone bruising and damage to other parts of the knee, increasing the athlete’s risk of developing osteoarthritis in years to come. Fortunately, not everyone who ‘does their ACL’ needs surgery as other ligaments and muscles help to stabilise the knee. The decision to have surgery depends on the type of damage and if the athlete wants to return to elite competition. There is a high success rate for ACL repair with surgery, but an athlete needs to be dedicated to a rehabilitation program and can expect to be out of competition for up to 12 months.

Jodi Richardson recently completed her PhD at Monash University. Originally a Physical Education and Chemistry teacher, Jodi completed an Honours degree in Exercise and Sports Science before completing her PhD investigating the effect of progressive eccentric training on hamstring muscle properties, and the application of this research to hamstring injury prevention in Australian Rules football. Jodi has presented her research both nationally and internationally, and was recently invited to present at the Australian Conference of Science and Medicine in Sport. She is a keen writer with an avid interest in Sports Science.