What it means
The anterior cruciate ligament is a strong band inside the knee that links the thigh bone to the shin bone. It stops the shin from sliding forward and helps control twisting. It usually tears during a sudden pivot, a change of direction or an awkward landing. On MRI a torn ACL may look broken, swollen, sagging or missing. A partial tear leaves some fibers intact; a complete tear goes all the way through.
When it matters
A complete tear can make the knee feel loose or give way, especially in sports with turning and jumping. The MRI also looks for injuries that often come with it, such as bone bruises and meniscal tears. Partial tears are often managed without surgery. After a complete tear, some people do well with focused rehabilitation. Others, often active people with an unstable knee, are offered surgery to rebuild the ligament.
Questions to ask your doctor
- Is the tear partial or complete?
- Were other parts of the knee injured, such as a meniscus or cartilage?
- Is rehabilitation alone an option, or should I see a knee surgeon?
