The ACL is very important for the stability of the knee. It usually tears following a twist with the foot planted in the ground and the knee bent. People often hear it snap. The knee suddenly gives way. It is common in Footballer & Skiing.
Symptoms include pain, severe swelling and some time later, instability of the knee. The menisci often tear at the same time.
It has been common practice to reconstruct torn ACL’s though recent studies have challenged whether this procedure is really necessary in most people. It is possible for many people to follow a rehabilitation programme and regain a stable knee without surgery.
A landmark study published in the New England Journal of Medicine (NEJM) in 2010 demonstrated that many people don’t need surgery:-