What is an ACL injury? A deep dive into football's most feared injury

The anterior cruciate ligament (ACL) is a crucial band of tissue in the center of the knee that provides stability. When it's torn, a footballer often experiences immediate pain, swelling, and a feeling of the knee "giving way." This type of injury is commonly caused by rapid changes in direction or awkward landings after a jump, making it a frequent and feared occurrence on the pitch. For many athletes, an ACL tear means missing most, if not all, of a season, with a typical recovery period spanning six to nine months. Recent examples include James Maddison and Levi Colwill, who both sustained ACL injuries in the pre-season, sidelining them for the majority of the current campaign.

Why does ACL recovery take so long?

The reason for the extensive recovery time lies in the complex nature of the injury and the rehabilitation process. According to physiotherapist Ben Warburton, who has worked with elite rugby and football teams, a player needs a minimum of six months after surgery to become match-fit. The initial phase is focused on allowing the trauma to the knee to subside, which can take up to three months. After that, the focus shifts to conditioning, strengthening the leg, and gradually reintroducing running and training.

Warburton warns that returning any earlier than six to nine months is a "massive risk" because players are more likely to re-aggravate the injury. He notes that the timeline can sometimes be influenced by a player's importance to the team, but the safest and most recommended route is to take the full time needed for a complete recovery.

Can an ACL injury end a football career?

While a serious ACL injury was once a career-ending threat, modern medicine has drastically improved a player's chances of returning to the sport. Today, most footballers who undergo ACL surgery have a 90-95% chance of returning to playing. This progress is due to advancements in technology and research, which have provided surgeons with better techniques and more effective graft options.

RELATED

Liverpool's new youngster Leoni suffers career-threatening ACL injury on debut

However, the risk is not entirely gone. The chance of a player re-injuring their ACL is at its highest in the first 12 months after their return. This is often due to a loss of quad strength and increased fatigue as they ramp up their training and match time. For this reason, a carefully managed return and consistent monitoring are crucial for a successful comeback.

Why are ACL injuries so common in women's football?

Studies have shown that female footballers are two to six times more likely to suffer an ACL injury than their male counterparts. This is a significant issue that has led to a number of high-profile players, such as Leah Williamson, Beth Mead, and Vivianne Miedema, being sidelined in recent years.

While research is ongoing, anatomical differences are believed to be a major factor. Women have a wider pelvis to facilitate childbirth, which creates a greater "Q angle"—the angle between the quadriceps muscle and the patellar tendon. This can cause the knee to move inward during movements, placing increased stress on the ACL. Furthermore, new research funded by FIFA is exploring whether hormonal fluctuations during menstrual cycles may also be contributing to the rise in these injuries.