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How Do You Know if You Tore Your ACL?

man suffering from knee pain
Knee injuries can be painful and debilitating. Your ACL (anterior cruciate ligament) is a tissue band of ligaments that hold the knee bones together. The function of the ACL is to prevent your shinbone from sliding out in front of your thighbone.

What Is ACL Injury?

An ACL injury is a sprain or tear of the ACL that happens to most people when they are playing sports. There is a risk for an ACL injury in activities involving jumping and landing, sudden stops, or changes in direction (like in football and soccer).

Many people who experience an ACL injury report hearing or feeling a "pop" in their knee when the injury occurs. The knee can swell, feel unstable, and it is too painful to bear weight.

A milder ACL injury can usually be treated by rest and physical therapy that help you recover your knee stability and strength. In more serious cases, surgery may be needed to replace the torn ligament followed by physical therapy.

What Are the Types of ACL Injuries?

An ACL injury is either a tear or sprain.

What Is an ACL Tear?

An ACL tear is when the ACL is actually torn. The tear can be complete or partial.

What Is an ACL Sprain?

An ACL sprain is when the ACL is overstretched (but not torn).

How to Differentiate between ACL Tear and ACL Sprain?

ACL injuries are graded from 1 to 3.

Grade 1 Sprain: There is minimal stretching and some microscopic tearing of the ACL, but the ligament is intact and the joint is stable. Typically, surgery is not needed.

Grade 2 Sprain (Partial Disruption): Some tearing has occurred and there is a separation of the ligament fibers. There is moderate knee instability. Based on the person's activity level and the degree of instability, this grade may or may not require surgery.

Grade 3 Sprain (Complete Disruption): There is a complete tear in the ligament fibers. The ligament is completely disrupted, and there is an unstable knee joint. Surgery is usually needed.

How Do You Know If Your Tore Your ACL?

If you hear a loud pop in your knee when you’re being injured, followed by swelling, pain, and knee instability, chances are you have an ACL tear.

What Are the Symptoms of an ACL Tear?

Signs and symptoms of an ACL injury usually include:

  • A loud "popping" in the knee
  • Severe pain
  • Rapid swelling
  • Loss of range of motion
  • Knee instability where the knee feels like it will buckle and cannot support the weight

How to Diagnose an ACL Tear?

Your doctor will manipulate your knee to see if there is an ACL tear. Imaging tests, such as an MRI or X-rays (to rule out a fracture) may also be performed.

How to Prevent an ACL Tear?

You can help prevent an ACL tear by:

  • Exercise training that strengthens your leg muscles, and core lower abdomen, pelvis and hips).
  • Exercise training that develops the proper sports techniques and knee position for pivoting, cutting, jumping and landing motions.

When Should You See a Doctor for an ACL Tear?

Seek your doctor right away if any knee injury causes popping noises or other signs of an ACL injury to see how severe the injury is and to receive prompt, proper treatment.

NY Orthopedics Knee Center explores nonsurgical treatment options whenever possible. When surgery is necessary, we offer the latest, state-of-the-art procedures including arthroscopic ACL repair surgery, which allows for better outcomes and faster recovery times. Call 212-737-3301 or fill out the form on this page today to make an appointment.



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