Glossary
Anterior cruciate ligament (ACL)
Quick answer
The anterior cruciate ligament (ACL) is a strong band inside the centre of the knee that runs from the femur to the tibia. It stops the shin sliding forward and controls rotation when you twist, cut or land, as Doha knee surgeon Dr. Pablo Gelber tells patients at Aman Hospital.
What it is
The ACL is one of two cruciate ligaments, so called because they cross each other like an X in the middle of the knee. It runs from the back of the femur, inside the notch between the condyles, forwards and down to the front of the tibial plateau. It is made of tightly packed collagen fibres and contains nerve endings that help your brain sense the knee's position.
Why it matters for patients
The ACL is most often torn without contact, when the foot is planted and the knee twists or buckles inwards: changing direction in football, landing in basketball or handball, or turning sharply on a padel court. People often describe a pop, rapid swelling and a knee that feels loose or gives way afterwards.
The ACL has a limited ability to heal on its own once fully torn. Some people cope well with physiotherapy and lower-demand activities, while many who want to return to pivoting sport choose ACL reconstruction. Untreated instability can lead to further meniscus and cartilage damage.
How it is examined
A surgeon tests the ACL with the Lachman and pivot shift tests, which check forward and rotational movement of the tibia. MRI confirms a tear and shows associated damage to the menisci, cartilage and bone.
Frequently asked questions
Can you walk with a torn ACL?
Usually, yes, once the early swelling settles. Walking in a straight line is often fine; problems tend to appear when twisting, pivoting or changing direction.
Is a partial ACL tear the same as a full tear?
No. Some partial tears leave the knee stable and are managed with rehabilitation. The decision depends on examination, MRI and how the knee behaves during activity.
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