Will you reinjure your ACL?

As someone who has ruptured the ACL in one knee, you are more likely to rupture the ACL in your other knee than those who have not had an ACL injury. Your age, the type of sport you play, your strength, and genetic factors all influence the risk. About 1 in 5 people who have had ACL surgery have a second ACL injury (in either knee). This risk increases to 1 in 4 among those who return to pivoting sports.

You have a higher risk of reinjury (your other ACL or your surgically repaired ACL) if you are a young athlete (less than 20 years of age), are Māori or from a Pacific community, or if you have surgery early (less than a year) after your injury.

You are also more likely to injure your ACL in either knee if you return to pivoting sports and if you return to sport before you are ready (physically or psychologically).

Your physio can help you reduce your risk of injury (or reinjury) when you reach that stage of your rehab. There are strength, balance, and coordination training programmes that can decrease the risk of ACL rupture by about 50% (such as, Power Up To Play).

Understanding future injury risk

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People who have ruptured one ACL ligament are 4 to 6 times as likely to have another ACL injury (in the same knee, if their ACL heals or is reconstructed, or in the opposite knee) as those who have not had an ACL injury.

About 1 in 5 people who have had ACL reconstruction surgery have a second ACL injury (in either knee).

This risk increases to 1 in 4 among those who return to pivoting sports (Wiggins et al. 2016).

Assessment of risk

The Strategic Assessment of Risk and Risk Tolerance (StARRT) model can help to estimate the risks of different short- and long-term outcomes and highlight factors that may influence acceptable risk.