Anterior Cruciate Ligament (ACL) Rupture

What Is It

The anterior cruciate ligament (ACL) is one of the central stabilising structures of the knee, preventing the shin bone (tibia) from sliding forward relative to the thigh bone. A rupture occurs when the force on the joint exceeds the ligament's tensile strength — most often in sports involving sudden deceleration, jumping and rapid changes of direction, such as football, basketball, handball and skiing.

Signs & Symptoms

• A sharp pain at the moment of injury, often accompanied by an audible "pop" in the knee
• Rapid swelling of the knee within the first few hours (haemarthrosis)
• A feeling of instability — the knee "gives way" or "shifts" when pivoting
• Inability to continue the activity immediately after the injury
• Restricted range of motion due to pain and swelling

Cause & Mechanism

Most ruptures occur without direct contact — during sudden deceleration, a landing combined with trunk rotation, or a change of direction while the foot is planted. Risk factors include weak hamstrings and quadriceps, poor landing mechanics, a previous injury, and, in certain sports, anatomical and hormonal differences that increase risk.

Diagnosis

Clinical examination includes the Lachman test and the anterior drawer test, which assess the degree of joint instability. The finding is confirmed with an MRI scan, which also reveals any associated meniscus or cartilage damage — common alongside an ACL rupture.

Treatment With Us

For athletes planning a return to contact sport, the standard of care is surgical ligament reconstruction (typically using an autograft from the patient's own tendon), followed by a structured, phased rehabilitation programme. For lower activity demands, a conservative approach built around strengthening the muscles supporting the knee may be sufficient — we make this decision together with the patient after assessing lifestyle and sporting goals.