The anterior cruciate ligament (ACL) is a ligament in the middle of your knee, its main role is to prevent excessive tibial anterior, medial and lateral rotation. Valgus Force is where the knee lies or directs inwards during an activity (Knocked Knees).

Typically, ACL injuries occur via non- contact, low energy and contact mechanisms likely to injure during sports that require; deceleration, cutting, rotational movements, especially during landing. Examples of sports include: Netball, Basketball, Football and Rugby.

Both genders are susceptible to injuries however, women are more likely to be injured in non-contact and males during contact. Overall, 1 in 3500 people obtain an ACL injury according to Larwa, J., Stoy, C., Chafetz, R., Boniello, M., and Franklin, C., (2021).

Among many other contributions it has been demonstrated that dynamic valgus is one of the most important modifiable risk factors, however even though you have an ACL injury, it dosen’t mean that you will lose your daily function.  



How do I know I’ve damaged my ACL and What should I do?

Generally, you will experience a sharp pain in the front of your knee and sometimes fall to the ground following contact or during a non-contact mechanism, which includes landing or extensive twisting of the knee in a straightened position. Swelling may become visible quickly and initially it is unlikely you will be able to fully weight bare.

What should I do if I suspect an ACL injury?

When ACL rupture occurs, you will be aware of it immediately. This usually happens when a large anterior force is applied, there will be high levels of pain, swelling and usually you are unable to weight bare. You may need to visit the hospital straight away for scans or seek advice/assessment from a physiotherapist as they will be able to assist you, provide information and guide you down the appropriate path to achieve the best outcome.


Case Study 1:

First ruptured his right ACL in December 2019 during a tackle with an opposing player. 3 months following his return, he re ruptured his ACL during a game when he was trying to hold off the goalkeeper and guard the ball. On both occasions he fell to the floor immediately in pain. Surgery was required after both incidents and rehabilitation of 9 months to a year.

Case Study 2:

In 2009, first ruptured his ACL, he then had a re-occurrence in 2011. The last incident occurred during his 5th game, when he was returning from the previous injury whilst playing football.

The period of risk for re rupturing the ACL in generally 0-18 months, following the initial return. Biomechanical factors have an impact on the potential risk of re injury, these are; abnormal loading patterns around the knee, valgus knee force, muscular imbalances, early return to sport and gender/age of athlete.

Prevention of injury is highly important, if a person required further surgery following re rupture, it could increase the chance of developing osteo arthritis, knee instability and potential struggle to return to particular jobs or sporting activities.

Prevention of injury and physiotherapy

At the start of rehabilitation, the aim is to gradually progress through to gaining back full range of motion, walking gait and reduced pain/swelling. This would be continued throughout as we build on strength, starting with inner range exercises and developing through into through range exercises. The Quadriceps are largely one of the main focus muscle groups at the start of rehabilitation, as generally a graft is taken from the hamstring to reconstruct the ACL and this needs to be approached with care as it goes through the healing process.

Progressing through the months, it is important to know that stages cannot be rushed. A variety of exercises to improve strength of all lower limbs, balance, flexibility, walking patterns, biomechanics, plyometrics and gradual return to activities/ sport.  

To get the best outcome, it is important to attend physiotherapy regularly, it’s not just exercise prescription but the management, monitoring and hands on treatment that is important in the recovery process.