ACL (anterior cruciate ligament) surgery is a type of knee ligament surgery that involves replacing the ACL in your knee.
The ACL is a band of tissue inside your knee. It helps your knee move and stay stable.
You can injure your ACL doing sports, or if you hit your knee, twist your knee, or quickly change direction or speed when running or walking.
Not all ACL injuries need surgery, but you may need it if you play a lot of sport and want to continue, or if you keep having problems with your knee after trying physiotherapy.
ACL surgery can involve replacing the ACL with a graft. The graft is usually taken from another part of your body, such as the hamstring.
You'll have the operation in hospital and you'll need physiotherapy afterwards. It usually takes several months or more to recover afterwards.
Page last reviewed: 17 July 2025
Next review due: 17 July 2028
