Athletes are often sidelined by this common knee sprain or tear known as an ACL injury. There is often an associated injury to other structures in the knee joint. Surgical repair is often required. Keep reading to learn more about causes, symptoms and treatments.

Causes & Triggers

  • High-impact collision or direct blow
  • Incorrect landing
  • Slowed pace while running
  • Sports injuries (especially soccer, football, basketball)
  • Sudden stopping or directional change
  • Possibly pelvic or lower leg alignment (in females)

Signs & Symptoms

  • Feeling of instability or “giving out”
  • Pain
  • Swelling
  • Some difficulty and discomfort with walking and range of motion

Tips & Treatments

  • Anterior cruciate ligaments (the crisscross supporters inside of the knee) control the knee’s back-and-forth motion.
  • Severity of ACL injuries are graded as follows:
    • Mild-Grade 1: Light damage, slight stretching of the ligament
    • Moderate-Grade 2: Partial tear; sprained and stretched to point of being “loose”
    • Severe-Grade 3: Complete tear with instability of joint
  • Female athletes are more likely than males to get an ACL injury (in certain sports).
  • Diagnosis is typically made only with a physical exam, although X-rays or an MRI may be ordered.
  • Depending on severity, surgery may be required to restore full function.