Anterior Cruciate Ligament (ACL) Sprain or Tear

What is an anterior cruciate ligament (ACL) injury?

A sprain is a joint injury that causes a stretch or a tear in a ligament. Ligaments are strong bands of tissue that connect one bone to another. The anterior cruciate ligament (ACL) is one of the major ligaments in the middle of the knee. It connects the thigh bone (femur) to the shin bone (tibia). This ligament, along with the posterior cruciate ligament, helps keep the knee stable and protects the femur from sliding or turning on the tibia.

Sprains are graded I, II, or Ill depending on their severity:

Grade I Sprain: pain with minimal damage to the ligaments
Grade II Sprain: more ligament damage and mild looseness of the joint
Grade III sprain: the ligament is completely torn and the joint is very loose or unstable.

How does it occur?

The anterior cruciate ligament is frequently injured in forced twisting motions of the knee. It may also become injured when the knee is straightened further than it normally can straighten (hyperextended). It sometimes occurs when the thigh bone is forcefully pushed across the shin bone, such as with a sudden stop while you are running or a sudden transfer of weight while you are skiing.

What are the symptoms?

There is usually a loud, painful pop when the joint is first injured. This is often followed by a lot of swelling of the knee within the first several hours after the injury. This swelling is called an effusion and is made up of blood in the knee joint. lf you have torn your anterior cruciate ligament in an injury that occurred months or years ago and you haven’t had reconstructive surgery, you may have the feeling that the knee is giving way during twisting or pivoting movements.

How is it diagnosed?

Your health care provider will examine your knee and may find that your knee has become loose. If you have swelling in the joint, he or she may decide to remove the blood in your knee with a needle and syringe. You may need x-rays to see if there is an injury to the bones in your knee. An MRI (magnetic resonance imaging) scan may also be done and should clearly show the condition of your ACL (as well
as that of other ligaments and cartilage).

How it is treated?

• Put an ice pack on your knee for 20 to 30 minutes every 3 to 4 hours for 2 or 3 days or until the pain goes away.
• Keep your knee elevated whenever possible by placing a pillow underneath it until the swelling goes away.
• Take an anti-inflammatory medication or other drugs prescribed by your health care provider.
• Do the exercises recommended by your health care provider or physical therapist.

Your provider may recommend that you:

• Wrap an elastic bandage around your knee to keep the swelling from getting worse.
• Use a knee immobilizer initially to protect the knee.
• Use crutches.

For complete tears, you and your health care provider will decide if you should have intense rehabilitation or if you should have surgery followed by rehabilitation. The torn anterior cruciate ligament cannot be sewn back together. The ligament must be reconstructed by taking ligaments or tendons from another part of your leg and connecting them to the tibia and femur.

Once you are able to walk without pain or a limp, your provider may refer you for formal physical
therapy and/or you may begin the following exercises at home:

Standing Calf Stretch
Facing a wall, put your hands against the wall at about eye level. Keep the uninjured leg forward and your injured leg back about 12–18 inches behind your uninjured leg. Keep your injured leg straight and your heel on the floor and keep your toes pointed toward the wall. Next, do a slight lunge by bending the knee of the forward leg. Lean into the wall until you feel a stretch in your calf muscle. Hold this position for 30–60 seconds and repeat 3 times.

Hamstring Stretch
Lie on your back and bring the affected leg toward your chest. Grab the back of your thigh and try to extend your leg. Hold this position for 30–60 seconds, feeling a stretch in the back of your thigh. Repeat 3 times. You may also try this with a towel around your foot if it is more comfortable.

Quadriceps Stretch
Stand sideways to a wall, about an arm’s length away, with your injured leg toward the outside. Facing straight ahead, keep the hand nearest the wall against the wall for support. With your other hand, grasp the ankle of your injured leg and pull your heel up toward your buttocks. Do not arch or twist your back. Hold this position for 30 seconds. Repeat 3 times.

Quadriceps Sets
Sit on the floor with your injured leg straight in front of you. Press the back of your knee down while tightening the muscles on the top of your thigh. Concentrate on tightening the muscles on the inner side of your kneecap. Hold this position for 5 seconds. Complete 3 sets of 10.

Straight Leg Raise
Sit on the floor with the injured leg straight and the other leg bent, foot flat on the floor. Pull the toes of your injured leg toward you while pressing the back of your knee down and tightening the thigh muscles. Raise your leg 6–8 inches off the floor and hold for 5 seconds, then slowly lower. Complete 3 sets of 10.

Abduction
Lie on your uninjured side, leaning on the elbow of your uninjured side and using the arm of the injured side in front of you to stabilize your body. Slowly lift the injured leg up, hold for 5 seconds, then lower slowly. Keep your hips steady and do not roll forward or backward. Complete 3 sets of 10.

Adduction
Lie on your injured side with your top leg bent and foot placed flat in front of the injured leg, which remains straight. Raise your injured leg as far as comfortable and hold for 5 seconds. Keep your hips still while lifting. Slowly lower your leg. Complete 3 sets of 10.

Prone Hip Extension
Lie on your stomach. Squeeze your buttocks together and raise your injured leg 5–8 inches off the floor. Keep your back straight and your hips level. Hold your leg up for 5 seconds, then lower. Repeat 10 times. Do 3 sets of 10. Do not let your hip roll open as you lift your leg.

Clamshells
Lie on your side with your knees slightly bent, keeping your legs and ankles together. Open and close your knees like a clam by lifting your top knee until it is parallel with your hip. Keep your feet together and move slowly and with control, as if someone is resisting your knee. Complete 3 sets of 10.

Bridge with Abduction and Resistance (Banded Bridges)
Lie on your back with your knees bent to 90 degrees and your feet flat on the floor. Place a tied resistance band just above your knees. Bring your feet and knees apart to hip or shoulder width and maintain tension in the band. Press into your heels and lift your hips into a bridge. Hold at the top for 3–5 seconds, then slowly lower. Do not allow the space between your knees to decrease. Complete 3 sets of 10 repetitions.

You may consider having reconstructive ACL surgery if:

• Your knee is unstable and gives out during routine or athletic activity.
• You are a high-level athlete and your knee could be unstable and give out during you sport (for example, basketball, football, or soccer).
• You are a younger person who is not willing to give up an athletic lifestyle.
• You want to prevent further injury to your knee. An unstable knee may lead to injuries of the meniscus and arthritis.

You may consider not having the surgery if:

• Your knee is not unstable and is not painful and you are able to do your chosen activities without symptoms.
• You are willing to give up sports that put extra stress on your knee.
• You are not involved in sports.

If a growing child tears an ACL, the health care provider may recommend that surgery be postponed until the child has stopped growing.

When can I return to my sport or activity?

This depends on whether or not you have a complete tear of your ACL which requires surgery, or a
partial tear of the ACL. If surgery is recommended, please refer to the surgical recovery guidelines.
The goal of rehabilitation is to return you to your sport or activity as soon as is safely possible. If you
return too soon, you may worsen your injury, which could lead to longer healing times. Everyone
recovers at a different rate. Returning to your sport or activity will be determined by how soon your
knee recovers, not by how many days or weeks it has been since pain began. In general, the longer
you have symptoms before you start treatment, the longer it will take to get better.
You may safely return to your sport or activity when, starting from the top of the list and progressing
to the end, each of the following is true:

• You have full range of motion in the injured knee, compared to the uninjured knee
• You have full strength of the injured knee and hip compared to the uninjured knee and hip
  and are able to complete the above exercises without pain
• You can jog straight ahead without pain or limping
• You can sprint straight ahead without pain or limping
• You can jump on both legs without pain, and you can jump on the injured leg without pain
  Return to your sport at about 50% effort and increase by about 10% each week. Patients should
  progress slowly with cutting movements. If there is a feeling of your knee giving out on you during
  these movements, you should make an appointment with your provider. If you begin with pain, you
  may need to rest for a few days before returning to activities.

How can I prevent an Anterior Cruciate Ligament sprain?

Unfortunately, most injuries to the anterior cruciate ligament occur during accidents that are not preventable. However, you may be able to avoid these injuries by having strong thigh and hamstring muscles and maintaining a good leg stretching routine. In activities such as skiing, make sure your ski bindings are set correctly by a trained professional so that your skis will release when you fall.