ACL injury

Symptoms:

Signs and symptoms of an ACL injury may include:
 

• A loud "pop" sound
• Having a feeling of instability or "giving away" with weight bearing
• Severe pain
• Swelling of the knee, which usually worsens for hours after the occurrence of the injury
• The knee may still feel unstable after the swelling subsides; it may also feel like it's going to "give away" during pivoting or twisting movements

Generally, the longer a person waits before seeking treatment, the longer it will take to get better, so if a popping sound, severe pain and\or a feeling that the knee is giving out is experienced, a person should see a doctor. Additionally, if the knee feels loose or unable to support a person's weight, they should also seek medical treatment.
 

Causes:

The ACL, which is one of two ligaments that cross in the middle of the knee, connects the femur (thighbone) to the tibia (shinbone) and helps stabilize the knee joint. Ligaments are strong bands of tissue that attach one bone to the other.

Most ACL injuries occur while performing fitness activities or sports. When a person pivots with their foot firmly planted, or when a person suddenly slows down to change direction, their ligament may tear.

Basketball, gymnastics and soccer, which are sports that involve running, pivoting, jumping and turning sharply, put the knee at risk. A football tackle or motor vehicle accident could cause an ACL injury. An ACL injury may also be caused during a fall in downhill skiing when the tibia becomes pushed forward below the femur. However, in most cases, ACL injuries occur without such contact.
 

Complications:

Until the injured ligament has healed, a person may have to take time off work, school and sports and stop doing the activities that cause pain.

Some of the other complications of an ACL injury may include:

Arthritis:
Even if a person has had surgery to reconstruct the ligament, arthritis may still occur. The early onset of osteoarthritis, the condition in which the joint cartilage deteriorates and its smooth surface becomes rough, is one of the common long-term complications. After about a decade or two of an ACL injury, half the people develop osteoarthritis in the involved joint.

Torn meniscus:
A tear of the meniscus, which is the cartilage in the knee between the thighbone and shinbone, may also be caused by an ACL injury. The risk of future joint problems will increase with a cartilage tear.
 

Treatments:

Reducing pain and swelling in the knee, regaining normal joint movement and strengthening the muscles around the knee is what the initial treatment for an ACL injury will focus on. Then, it will be decided whether the patient needs intense rehabilitation alone or surgery in addition to rehabilitation. The right choice will depend on the extent of damage to the knee, the person's willingness to modify his/her activities as well as other factors. If a child, whose bones are still developing, injures his\her ACL, he/she may be recommended postponing the surgery until the bones become fully grown.

Short term treatments:

• Ice: The knee should be iced at least for 20 minutes every two hours during the day
• Pain killers: In order to relieve pain, such as ibuprofen
• The knee should be elevated
• The person should work with a physical therapist on range-of-motion and muscle-strengthening exercises
• A flexible or elastic bandage should be wrapped around the knee, and a splint or crutches should be used when walking

In surgery for reconstructing the ligament, a piece of tendon is taken from a different part of the leg and connected to the thighbone and shinbone (autograft). In case the person's tendons don't provide the best replacement for the injured ligament, he/she may be recommended using a tendon from a cadaver (allograft), which has been carefully screened and tested for diseases.

Surgery should be considered:
 

• If other parts of the knee were also injured, such as the meniscus or other ligaments.
• When during daily activities and sports the knee feels unstable as if it would give way.
• The person leads an active life and wants to resume heavy work, sports or other recreational activities.
• To prevent further injury to the knee.

During surgery, a thin instrument called arthroscope is inserted with a light and a small camera into one or two small incisions, allowing the surgeon to see the inside of the knee joint and repair it. This is an outpatient procedure using arthroscopic techniques.

The rehabilitation program after the surgery includes wearing a knee brace, working with a physical therapist and avoiding activities that put undue stress on the knee. Almost nine out of ten people who have undergone an ACL reconstruction surgery, have satisfactory knee stability and good to excellent results. Additionally, most people can return to their sports about six months after surgery.

A non-surgical rehabilitation program will involve modifying the activities and knee bracing, as well as physical therapy. As long as a person is willing to give up sports and other activities that place extra stress on the knee, this approach can be effective.

Rehabilitation alone can be considered in case the person:
 

• Has advanced knee arthritis
• Leads a fairly sedentary life and doesn't participate in sports that include jumping or pivoting
• Has a partial tear
• The cartilage of the knee hasn't been damaged
• The affected knee doesn't hurt or feel unstable during normal activities
   

Prognosis:

Not available

Expert's opinion: