ACL-Injury and Operation:

One of the most common knee injuries is an anterior cruciate ligament sprain or tear.

Athletes who participate in high demand sports like soccer, football, and basketball are more likely to injure their anterior cruciate ligaments.

If you have injured your anterior cruciate ligament, you may require surgery to regain full function of your knee. This will depend on several factors, such as the severity of your injury and your activity level.





Anatomy of the Knee Joint:



Three bones meet to form your knee joint: your thighbone (femur), shinbone (tibia), and kneecap (patella). Your kneecap sits in front of the joint to provide some protection.

Bones are connected to other bones by ligaments. There are four primary ligaments in your knee. They act like strong ropes to hold the bones together and keep your knee stable.


Collateral Ligaments

These are found on the sides of your knee. The medial collateral ligament is on the inside and the lateral collateral ligament is on the outside. They control the sideways motion of your knee and brace it against unusual movement.

 Cruciate Ligaments

These are found inside your knee joint. They cross each other to form an "X" with the anterior cruciate ligament in front and the posterior cruciate ligament in back. The cruciate ligaments control the back and forth motion of your knee.

The anterior cruciate ligament runs diagonally in the middle of the knee. It prevents the tibia from sliding out in front of the femur, as well as provides rotational stability to the knee.

About half of all injuries to the anterior cruciate ligament occur along with damage to other structures in the knee, such as articular cartilage, meniscus, or other ligaments.

Injured ligaments are considered "sprains" and are graded on a severity scale.

Grade 1 Sprains. The ligament is mildly damaged in a Grade 1 Sprain. It has been slightly stretched, but is still able to help keep the knee joint stable.

Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to the point where it becomes loose. This is often referred to as a partial tear of the ligament.

Grade 3 Sprains. This type of sprain is most commonly referred to as a complete tear of the ligament. The ligament has been split into two pieces, and the knee joint is unstable.

Partial tears of the anterior cruciate ligament are rare; most ACL injuries are complete or near complete tears.


The anterior cruciate ligament can be injured in several ways:

·         Changing direction rapidly

·         Stopping suddenly

·         Slowing down while running

·         Landing from a jump incorrectly

·         Direct contact or collision, such as a football tackle

Several studies have shown that female athletes have a higher incidence of ACL injury than male athletes in certain sports. It has been proposed that this is due to differences in physical conditioning, muscular strength, and neuromuscular control. Other suggested causes include differences in pelvis and lower extremity (leg) alignment, increased looseness in ligaments, and the effects of estrogen on ligament properties.


When you injure your anterior cruciate ligament, you might hear a "popping" noise and you may feel your knee give out from under you. Other typical symptoms include:

·         Pain with swelling. Within 24 hours, your knee will swell. If ignored, the swelling and pain may resolve on its own. However, if you attempt to return to sports, your knee will probably be unstable and you risk causing further damage to the cushioning cartilage (meniscus) of your knee.

·         Loss of full range of motion

·         Tenderness along the joint line

·         Discomfort while walking


Physical Examination and Patient History

During your first visit, your doctor will talk to you about your symptoms and medical history.

During the physical examination, your doctor will check all the structures of your injured knee, and compare them to your non-injured knee. Most ligament injuries can be diagnosed with a thorough physical examination of the knee.

Imaging Tests

Other tests which may help your doctor confirm your diagnosis include:

X-rays. Although they will not show any injury to your anterior cruciate ligament, X-rays can show whether the injury is associated with a broken bone.

MRI. This study creates better images of soft tissues like the anterior cruciate ligament. However, an MRI is usually not required to make the diagnosis of a torn ACL.



Treatment for an ACL tear will vary depending upon the patient's individual needs. For example, the young athlete involved in agility sports will most likely require surgery to safely return to sports. The less active, usually older, individual may be able to return to a quieter lifestyle without surgery.

Nonsurgical Treatment

A torn ACL will not heal without surgery. But nonsurgical treatment may be effective for patients who are elderly or have a very low activity level. If the overall stability of the knee is intact, your doctor may recommend simple, nonsurgical options.

Bracing. Your doctor may recommend a brace to protect your knee from instability. To further protect your knee, you may be given crutches to keep you from putting weight on your leg.

Physical therapy. As the swelling goes down, a careful rehabilitation program is started. Specific exercises will restore function to your knee and strengthen the leg muscles that support it.


Surgical Treatment




Rebuilding the ligament. 

Most ACL tears cannot be sutured (stitched) back together. To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. Your doctor will replace your torn ligament with a tissue graft. This graft acts as a scaffolding for a new ligament to grow on.

Grafts can be obtained from several sources. Often they are taken from the patellar tendon, which runs between the kneecap and the shinbone. Hamstring tendons at the back of the thigh are a common source of grafts. Sometimes a quadriceps tendon, which runs from the kneecap into the thigh, is used. Finally, cadaver graft (allograft) can be used.

There are advantages and disadvantages to all graft sources. You should discuss graft choices with your own orthopaedic surgeon to help determine which is best for you.

Because the regrowth takes time, it may be six months or more before an athlete can return to sports after surgery.










 Surgery to rebuild an anterior cruciate ligament is done with an arthroscope using small incisions. Arthroscopic surgery is less invasive. The benefits of less invasive techniques include less pain from surgery, less time spent in the hospital, and quicker recovery times.





Unless ACL reconstruction is treatment for a combined ligament injury, it is usually not done right away. This delay gives the inflammation a chance to resolve, and allows a return of motion before surgery. Performing an ACL reconstruction too early greatly increases the risk of arthrofibrosis, or scar forming in the joint, which would risk a loss of knee motion.

Whether your treatment involves surgery or not, rehabilitation plays a vital role in getting you back to your daily activities. A physical therapy program will help you regain knee strength and motion.




If you have surgery, physical therapy first focuses on returning motion to the joint and surrounding muscles. This is followed by a strengthening program designed to protect the new ligament. This strengthening gradually increases the stress across the ligament. The final phase of rehabilitation is aimed at a functional return tailored for the athlete's sport.


Physiotherapy after Operation:


Rehabilitation of an ACL reconstructed knee begins days after  surgery. Most patients are fitted with a full leg/knee brace & crutches, and are given exercises immediately post op.





The knee brace given to you immediately after surgery must be worn in locked extension (straight leg) while walking and sleeping. You may take the brace off when doing exercises and/or the CPM machine. Brace hinges must be at the level of the knee cap. You may loosen or tighten the brace straps as necessary. It is important to keep the top straps tight in order to prevent the brace from moving up and down on the leg. You will need to wear the brace for about 4-6 weeks. While putting your brace on, it is easier to keep your leg straight and your thigh muscle tight.




You may shower 48 hours after surgery, however you must place a plastic bag over the brace while showering or you have the option to take off the brace to shower. Whatever you decide to do please use CAUTION!! Be careful not to slip, twist, or fall. A stool placed in the shower so you can sit is a great idea so you can stabilize your knee. Do not soak in a bath tub, hot tub, or pool until the doctor tells you it is O.K. to do so. Once you are done showering pat the wound dry.



Remove all cotton and yellow gauze 48 hours after your surgery. Please leave steri-strips (white paper strips) on your wound until you see the doctor. Reapply ACE bandage. You do not need to place a new dressing on your knee.




When you are not walking, your leg should be straight with a pillow under your foot or ankle (not behind your knee). Try to elevate knee as much as possible to reduce swelling. This means that the level of the knee must be above the heart.



Never Put Anything Behind Your Knee!

Physical therapy & CPM will help your regain knee flexion (bending). However, being able to fully extend (straighten) your knee soon after surgery is vital! If full extension is not achieved within the first eight weeks, a second surgery may be necessary. With this in mind, you must never Never NEVER put anything under your knee when you are resting, sleeping, or propping your leg up. The pillow must go under the heel.



You should ice the knee as often as possible (especially after exercising) to reduce swelling and discomfort. Do not ice the knee more than 20 minutes at a time. Let the knee warm up before reapplication. Avoid getting your wound wet.



Use the crutches when walking as the physical therapist taught you in the hospital. Put as much weight on your leg as you can tolerate. When you feel comfortable walking without your crutches you may do so. This usually takes about 1-2 weeks.


Follow-up Visit

You need to see the doctor frequently after the Operation and to put a future plan for the following weeks and the date of suture removal if nessesary.




Common Concerns


Numbness around the incision site on the outside part of the knee is a result of a disruption of a superficial nerve during the operative procedure. Most of this will resolve over time but a small area the size of a quarter usually remains numb. This is unavoidable because of the proximity of the nerve to the incision.

A sudden rush or feeling of fullness with pain when going from a sitting to a standing position in the knee is common after surgery.

Bruising and/or swelling of the shin and ankle is common after surgery. This is caused by bleeding from the bone (which is cut during surgery) into the area just below the skin. To relieve this discomfort it is best to ice the leg. If at any time you have discomfort, swelling, or redness in the calf (behind the leg between the knee and the ankle) please call the doctor immediately.




Straight Leg Raise (SLR)

Lie on your back with your knee brace locked. Bend your other knee so that you can put your foot flat on the bed. Contract your quad tightly before you raise your leg (see quad set). Slowly raise your braced knee until the ankle is approximately 12 inches off the bed. Slowly lower the leg back to the starting position.

Please note: This patient is in a later stage of rehab and is lifting his ankle more than 12 inches.


Quad Sets

While sitting on a flat surface with your legs straight, tighten your thigh muscle while pushing the back of your knee into the bed. You cannot do enough of these. This exercise will help get your leg straight. Also, the sooner you regain your quad strength the earlier you will get permission to unlock the brace.


Heel Slides

Lie on your back with your knee brace removed. Slowly bend your knee, sliding your foot along the surface of the floor. Once you have bent your knee as much as possible, slide your foot back down until your knee is straight, you may use your other leg to help in either direction.


Patella Mobilizations

Sit on your bed or floor with your leg straight and quad relaxed. Hold your knee cap with one hand on each side. Gently, move your kneecap side to side.


Hip Abduction

Lie on your uninjured side and bend your noninvolved knee. With your surgically repaired knee held straight, slowly raise your leg toward the ceiling (12 inches), then slowly lower it again. This exercise can be performed with or without the knee brace.

Please note: This patient is in a later stage of rehab and is lifting his ankle more than 12 inches.


Hip Adduction

Lie on your side (surgically repaired side). Keep your lower leg (injured) straight. Bend your upper knee and place your foot in front of the bottom leg. Slowly raise the lower leg toward the ceiling (approximately 8 inches). Then slowly lower your bottom leg to the starting position.


Seated passive knee motion

While sitting on the edge of your bed or chair, let your knees bend and legs dangle over the edge. Place your noninvolved foot behind your other ankle and lift that leg until your knee is straight. Next, use your noninvolved leg to slowly lower your involved leg. Your will feel some discomfort as your surgically repaired knee bends. Repeat this exercise 10 times.




Prone Hangs

Lie on your stomach with both legs straight. Slowly push yourself toward the foot on your bed until your legs are hanging over the edge (up to the top of your knees). Allow your legs to hang there as tolerated. This exercise will help straighten yo