Q: What is an anterior cruciate ligament (ACL) injury?

Answer: The anterior cruciate ligament (ACL) is the most common knee ligament to injure. Every year there are about 30 ACL ruptures per 100,000 people.  The ACL is typically ruptured during a twisting, or pivoting movement. Playing football, netball, volley ball and skiing are amongst the most common ways to rupture the cruciate ligament, but there are many other causes.  The unfortunate victim often feels, or even hears a loud pop, or snap at the same time as their knee buckling, or giving way underneath them.  The knee typically swells up within hours. Over the next few weeks the knee is generally very sore and this results in quite a limp, but it then gradually settles down again with time. Often other ligaments and cartilages (menisci) will be injured at the same time, which can alter the rate of recovery.-- Mr Charles Willis-Owen, Consultant Knee Surgeon -- What is an anterior cruciate ligament injury?