The ACL is the Anterior Cruciate Ligament, which is one of the four major stabilising ligaments in the knee.
The ACL prevents the lower leg bone (the tibia) translating forward on the femur (the upper leg bone). A complete rupture of the ACL will mean the ligament has completely separated, leaving the knee in a very unstable state.
A complete rupture can be diagnosed by a Physiotherapist or Sports Therapist in the clinic - this is done through a physical examination. However this diagnosis will often be confirmed with additional imaging (scan).
The injury typically occurs when the foot is in contact with the ground and there is a twisting force at the knee.
***Here Micheal Owen ruptures his left ACL in the 2006 World Cup match against Sweden. Watch the youtube clip here.
Symptoms of the injury include:
If there has been a complete rupture of the ACL, surgery will be required in most cases. The elderly and the less active may avoid surgery, however most reasonably active people will be advised to have surgery. The recovery time following an ACL rupture, will vary but can be any where from 6 months to as long as 12 months.
- A loud pop / crack at the time of the injury
- Immediate swelling at the knee
- A feeling of instability in the knee
- The knee giving way
- Problems fully straightening the knee
- Tenderness on palpation of the front and inside aspect of the knee
The recovery time will be dependent upon the surgeons approach and whether any other structures such as the knee cartilage or other ligaments were also damaged in the injury.
Rehabilitation following surgery will focus on reducing the swelling, increasing the range of motion and restoring full strength around the knee.