Your knee joint has three bones — the:
Four ligaments hold the bones in place. The anterior cruciate ligament (ACL) crosses the middle of the knee diagonally, providing stability.
An ACL tear or sprain is a common knee injury and happens most often to athletes. Weekend warriors and non-athletes can also sustain an ACL injury.
You can injure your ACL during a stop/start motion, pivot, or quick direction change that causes the knee joint to:
The chance of injury is higher if more than one of these movements occurs at the same time.
An ACL tear or sprain often occurs during sports when you:
This type of injury is common in sports with lots of stop-and-go movements, jumping, or weaving like:
Falling off a ladder or missing a step on a staircase can also cause an ACL sprain or tear.
Like any other body part, the ACL gets weaker with age. A tear happens more easily in people older than age 40.
Many people who injure their ACL hear a popping noise in the knee.
Other common symptoms of ACL sprains or tears include:
ACL injury symptoms can vary widely among people.
Some people have a lot of pain, while others can walk around for a few hours after the injury. But, as the swelling in your knee increases, it's harder to walk and you lose range of motion.
Your UPMC Sports Medicine knee doctor can tell if you have an ACL injury. He or she will ask about your health history and examine your knees.
During the exam, your doctor will check both the injured and uninjured knee for:
Your doctor may use the Lachman test and pivot shift test to assess:
You also may need:
Doctors use a grade to diagnose how severe your ACL tear is.
Contact the UPMC Sports Medicine ACL Program today to learn more or make an appointment.