Anterior Cruciate Ligament (ACL) Injuries

When To Call a Doctor

Call your health professional immediately if you have an injury to your knee and:

  • You have severe pain in your knee.
  • Your knee appears to be deformed.
  • You have signs of damage to the nerves or blood vessels, such as numbness, tingling, a "pins-and-needles" sensation below the injury, an inability to move your leg below the injury, pale or bluish skin, or your leg feels cold.

Call your health professional today if:

  • Your knee begins to swell within 2 hours of the injury.
  • You hear a pop in your knee during an injury.
  • Your knee won't bear weight.
  • You are unable to straighten your leg completely.
  • Your knee is unstable, buckles, or gives out.
  • Your knee “locks” in one position.
  • You have had an anterior cruciate ligament (ACL) injury in the past and you have reinjured your knee.

Before your appointment, do not put weight on the injured knee; use crutches if necessary. Apply ice and wrap your knee in an elastic bandage or neoprene (synthetic rubber) sleeve with a kneecap hole. Rest and elevate the knee. Take a non-prescription anti-inflammatory drug to reduce swelling. For more information on first aid steps, see the Home Treatment section of this topic.

Watchful Waiting

Watchful waiting is a period of time during which you and your health professional observe your symptoms or condition without using medical treatment. Watchful waiting is not appropriate if knee pain is severe, your knee is deformed or swells immediately after an injury, or you are unable to bear any weight, either because of pain or instability.

Serious knee injuries need to be checked for possible broken bones as well as ligament or cartilage damage. Whenever immediate swelling follows an injury, there also may be torn blood vessels or damaged nerves in the knee. Your health professional will check your knee to make sure the blood supply to your leg is normal and the nerves are intact.

If you have occasional pain in your knee or your knee sometimes gives way or buckles, have your health professional check it. If you have damaged your ACL, it is important to get treatment so that your knee is appropriately managed, which may reduce the chance that you will get osteoarthritis in your knee.

Who To See

Your family doctor, general practitioner, or an emergency medicine specialist (for acute knee injury) can diagnose and treat most knee problems. You may be referred to a specialist, such as an orthopedic surgeon or a sports medicine specialist who is experienced with treating knee problems and injuries.

If surgery is considered, you may be referred to an orthopedic surgeon (possibly a sports medicine specialist) who is experienced in knee surgery.

To prepare for your appointment, see the topic Making the Most of Your Appointment


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Author: Douglas Dana
Robin Parks, MS
Last Updated: September 8, 2006
Medical Review: William M. Green, MD - Emergency Medicine
Adam Husney, MD - Family Medicine
David Bardana, MD, FRCSC - Orthopedic Surgery/Sports Medicine
Kathie Hummel-Berry, PT, PhD - Physical Therapy
Patrick J. McMahon, MD - Orthopedics

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Topic Contents
 Topic Overview
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 Cause
 Symptoms
 What Happens
 What Increases Your Risk
Arrow PointerWhen To Call a Doctor
 Examinations and Tests
 Treatment Overview
 Prevention
 Home Treatment
 Medications
 Surgery
 Other Treatment
 Other Places To Get Help
 Related Information
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