ACL Injury
The ACL (Anterior Cruciate Ligament) is one of the major ligaments in your knee. It connects the thighbone (femur) to the shinbone (tibia) and helps stabilise the knee, preventing forward movement and internal rotation of the tibia. This is especially important during activities like pivoting, cutting, or jumping.
An ACL injury occurs when the ligament is stretched, partially torn, or completely torn. This is a common injury in sports like football, netball, basketball, and skiing, It often occurs during a twist, sudden stop or change in direction, incorrect landing from a jump, and less commonly a direct blow to the knee.
Approximately 71 people in 100,000 experience an ACL injury in the UK each year, and this has been increasing over the past two decades. ACL injuries are more common amongst individuals aged 15–30 years, with a higher occurrence in males. However, female athletes have a 2 to 8 times higher risk of ACL tears compared to males in similar sports, due to differences in biomechanics, hormone levels, neuromuscular control, and joint anatomy.
At the time of injury, many patients report hearing a ‘popping’ or ‘snapping’ sound. It feels like a significant knee injury, and is associated with pain and swelling. One may experience difficulty putting weight through the knee and often there is a limited range of movement.
If there is a significant block to movement, there may be an associated meniscus injury. As the knee calms down from the initial injury, the dominant symptom of an ACL injury is the feeling of ‘giving way’, and the inability to ‘trust’ the knee.
An ACL injury is diagnosed through:
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Physical examination to assess the swelling, range of movement, and stability of the knee
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Imaging of the knee using an MRI (magnetic resonance imaging) scan
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Treatment depends on the severity of the injury, your activity level, and personal goals (e.g., returning to sports).
1. Non-Surgical (Conservative) Treatment
Injury to the ACL does not always necessitate surgical reconstruction, and many people can reagin stability and knee control without surgery. This option may be suitable for partial tears, individuals with low physical demands, and people who aspire to predominantly in-line activities (running, cycling, rowing) rather than pivot (twisting) sports.
Non-surgical treatment consists of a physiotherapy guided, specific strength and conditioning programme. If after physiotherapy rehabilitation the knee remains unstable, surgery can still be an option.
2. Surgical Treatment (ACL Reconstruction)
The ACL cannot be reliably repaired, and so surgical treatment consists of a reconstruction (replacement with a new ligament). This is appropriate for complete tears with knee instability, young active individuals, patients with coexisting repairable meniscus tears, and those who wish to return to pivoting sports.
It is important that the knee has no limitation prior to the surgery, and the muscles around the knee are strong. For this reason, preoperative physiotherapy (pre-habilitation) is often recommended.
Further information about ACL surgery can be found here.
Whether the treatment involves surgery or not, the aim is to provide you with a knee that is stable and allows you to live the life that you want to. Some patients will return to full activities without surgery, whilst others may decide to modify their activities to allow this rather than undergoing surgery.