The decision to have knee surgery will depend on the extent of damage to your anterior cruciate ligament (ACL), if there is other knee damage and if your quality of life is affected.

If your knee feels stable and you do not have an active lifestyle, you may decide not to have ACL surgery.

But delaying surgery could cause further damage to your knee, if it gives way or becomes unstable.

Your doctor will discuss options with you and assess if you need surgery, once swelling goes down and if rest and physio has helped to treat your symptoms.

When deciding whether to have ACL surgery, the following factors should be taken into consideration:

• your age – older people who are not very active may be less likely to need surgery
• your lifestyle – for example, whether you'll be able to follow the rehabilitation programme after having surgery
• how often you play sports – you may need to have surgery if you play sports regularly
• your occupation – for example, whether you do any form of manual labour
• how unstable your knee is – if your knee is very unstable, you're at increased risk of doing further damage if you do not have surgery
• whether you have any other injuries – for example, your menisci (small discs of cartilage that act as shock absorbers) may also be torn and may heal better when repaired at the same time as ACL reconstruction

If necessary, children can also have ACL reconstructive surgery. But as they're still growing, the procedure is likely to be modified to ensure that the growth areas are not affected.

It's a trickier operation and may need to be carried out by a surgeon with a special interest in childhood injuries.

If surgery is not possible, a brace and refraining from sports until the child is fully grown may be an alternative.