The anterior cruciate ligament (ACL) is an important band of connective tissue in the centre of the knee that helps to keep it stable.
When the ACL is injured it can cause pain, swelling and a feeling of the knee ‘giving way’, making it difficult to bear weight or participate in activities – particularly sport.
Scenarios that commonly lead to ACL injuries in football include rapid directional changes and landing after heading the ball.
If a footballer partially tears or ruptures their ACL, it often leads to them missing most – and in some cases, all – of a season, typically requiring six to nine months on the sidelines.
NFL star quarterback Patrick Mahomes suffered a torn cruciate ligament as Kansas City Chiefs ended their play-off hopes with defeat to the Los Angeles Chargers.
Since August, Premier League footballers James Maddison, Levi Colwill and Giovanni Leoni have all sustained ACL injuries.
Women’s Super League footballers Jill Baijings, Michelle Agyemang, Jessica Naz Ella Morris and Mayzee Davies have all suffered a similar fate.
Sometimes, recovery can take even longer. Aston Villa duo Tyrone Mings and Emiliano Buendia both missed the duration of the 2023-24 season and the start of the following season due to ACL injuries.
In some cases, players can struggle to reach the capabilities they once played at due to the severity of an ACL injury – and there’s the worry that the injury may return.
How long does an ACL tear take to heal?
How quickly a player recovers from ACL injury can depend on their age, the severity of the injury and how the individual reacts to surgery.
Ben Warburton is a physiotherapist experienced in ACL rehabilitation, having worked with Cardiff City, Wales’ national rugby union team and Scarlets.
Warburton says it will take a minimum of six months after surgery to get a player match-fit.
“Once you’ve had surgery, there’s a lot of trauma to the knee,” he explains. “Once that’s calmed down, you’ve got to take it easy for the first three months. When you get past that three-month mark, you can rehab.
“Then it’s a case of conditioning and training, getting the leg strong and getting the player back to running, training and games. That’s why it takes so long.”
Warburton says players who return to playing six months after ACL surgery are more likely to re-aggravate the injury than those who recover for nine months.
“You can go earlier [than six months], but it’s a massive risk,” Warburton adds.
“I don’t know many surgeons who’d recommend to that. It has obviously happened. It hasn’t not been successful, it’s just unbelievably high-risk.”
“A lot of it comes down to player profile as well,” he adds. “If they’re a really important player, you’re going to push them early. If they’re a developing player in the future, you’re going to probably go more towards nine months.”
Can an ACL injury end a football career?
As recently as 10 years ago, a serious ACL injury increased the likelihood that a footballer might have to retire.
But Warburton says nowadays, most footballers who have ACL surgery have between a 90-95% chance of returning to playing.
Advancements in technology and research are improving the management of ACL injuries, particularly in surgical decision-making and graft options.
Surgeons now have access to improved techniques for ACL reconstruction, including the transplant of a kneecap and hamstring tendons from donors.
“There’s so much research now on the best grafts and the strongest graft for an ACL, and success rates,” says Warburton.
“And there are so many tests that we put players through, through technology that wasn’t available even 10 years ago.”
Rates of a player reinjuring their ACL are heightened in the first 12 months following their return, meaning longer rest periods are key.
“What happens is players return and naturally their rehab goes down and their training and playing go up. So sometimes they lose quad [thigh muscle] strength and then with more game time fatigue kicks in,” says Warburton.
“Within the first year, really the first six months, you’ve got to be careful. I think once you get past that period, you’re a lot safer.”
Why are ACL injuries so common in women’s football?
Studies show female footballers are two to six times more likely to suffer an ACL injury than their male counterparts.
In 2022, then-Arsenal trio Leah Williamson, Beth Mead and Vivianne Miedema all suffered ACL injuries in quick succession.
Research as to why this type of injury is more prevalent in women is ongoing, but anatomical differences are believed to play a role.
“[Women] have what’s called a greater Q angle [the angle between the quadriceps muscle and the patellar tendon],” says Warburton, adding that this is because their pelvis is wider to facilitate childbirth.
A larger Q angle can cause the knee to move inward during movements such as jumping, which places more stress on the ACL.
Earlier this year, Fifa funded a research project into whether hormonal fluctuations during menstrual cycles could be contributing to the rise in ACL injuries in women’s football.
Thank you to Phil in Warwickshire for the question.
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