Anterior Cruciate Ligament – ACL Rehabilitation

The anterior cruciate ligament (ACL) is a dense group of connective tissue that extends from the femur to the tibia. The ACL is a key structure in the knee joint as it resists rotational loads and anterior translation of the tibia. It is one of the most frequently injured structures during high impact or sports activities.

Anatomy of Anterior Cruciate Ligament

Proximally, it inserts into the space at the posteromedial edge of the lateral femoral condyle and proceeds distally in an oblique and anteromedial direction, inserting anteriorly into the intercondylar space on the tibial plateau. The ACL consists of two functional bundles, anteromedial (AM) and posterolateral (PL). The AM bundle begins anterior and proximal to the femoral insertion and inserts into the anteromedial aspect of the tibial insertion. The PL bundle starts from the postero-distal of the femoral attachment and inserts posterolaterally of the tibial attachment. The AM bundle is thicker than the PL bundle at both the tibial and femoral attachments.

Biomechanics

The primary task of the ACL is to control the anterior translation of the tibia on the femur. It also controls rotational forces acting on the knee. It has been shown that the ACL is stretched more in tibial internal rotation than in tibial external rotation. Together with the posterior cruciate ligament (PCL), the ACL guides the instantaneous center of rotation of the knee, thereby controlling the joint kinematics. Although the anteromedial bundle is the primary restriction against anterior tibial translation, the posterolateral bundle tends to stabilize the knee in position near full extension, especially against rotational loads. Rupture of the posterolateral bundle causes an increase in hyperextension, an increase in external and internal rotation to anterior translation, and an increase in external rotation at mid-knee flexion; Rupture of the anteromedial bundle causes anterolateral instability with an increase in anterior translation in flexion, minimal increase in hyperextension, and minimal rotational instability.

Anterior Cruciate Ligament Rehabilitation Program

ACUTE PHASE

Physiotherapy management after anterior cruciate ligament injury, regardless of whether surgery will take place; It focuses on regaining range of motion, strength, proprioception, and stability. PRICE-POLICE-PEACE&LOVE should be used to reduce swelling and pain, provide full range of motion, and reduce joint effusion. Exercises should promote range of motion, strengthening of the quadriceps and hamstrings, and proprioception. Exercises should promote range of motion, strengthening of the quadriceps and hamstrings, and proprioception.

1. Quadriceps Strengthening

2. Ankle dorsi/plantar flexion

3. Knee flexion/extension in sitting position

4. Knee flexion in prone position

BEFORE SURGERY

RICE and electrotherapy agents can be applied a few weeks before surgery to reduce swelling and pain, provide full range of motion, and reduce joint effusion. This will help the patient gain better range of motion and strength after surgery. The patient should also be mentally prepared for the surgery. Before surgery, the injured knee should have little or no swelling, a full range of motion, and the patient should have a normal or near-normal gait. Preparing the knee for surgery is very important and the guidelines are:

1. Immobilize the knee. Use knee stabilizers or crutches for this. Prolonged use of the knee immobilizer should be limited to avoid quadriceps atrophy.
2. Control pain and swelling. Ice and anti-inflammatory medications are used to help control pain and swelling. Non-steroidal anti-inflammatory drugs are continued to be used for 7-10 days following acute injury.
3. Restore normal range of motion. Quadriceps isometric exercises, straight leg raises, and range-of-motion exercises should be started to achieve full range of motion as soon as possible.

Full extension is achieved by performing the following exercises:

– Passive Knee Extension

• Sit in a chair and place your heel on the edge of a stool or chair.
• Relax the thigh muscles.
• Allow the knee to sag under its own weight until maximum extension is achieved.

– Heel Props

• Place the heel on a rolled towel, making sure it is high enough to lift the thigh off the table.
• Allow the leg to relax into extension.
• Do this 3-4 times a day for 10-15 minutes each time.

– Prone hang

• Lie facedown on a table with your legs hanging over the edge of the table.
• Allow the legs to come to full extension.

Flexion is achieved by performing the following exercises:

– Passive knee bend

• Sit on the edge of a table and bend your knee under the influence of gravity.

– Wall Slides

• Lie on your back with the involved foot against the wall and bend your knee to allow the foot to slide off the wall. Use the other leg to apply downward pressure.

– Heel slides

• Heel shift is used to achieve final degrees of flexion.
• Bend your knee and pull the heel towards the hip. Wait 5 seconds.
• Straighten the leg by sliding the heel down and hold for 5 seconds.

– In the later stages of rehabilitation, heel slide, grasping the leg with both hands and pulling the heel towards the buttocks.

4. Increase muscle strength. When 100 degrees of flexion is reached, you can start working on muscle strength.

– Stationary Cycling: Use a stationary bike for 10-20 minutes twice a day to help build muscle strength, endurance, and maintain range of motion.

– Swimming is another exercise that can be done at this stage to build muscle strength and maintain your range of motion.

5. Mental preparation: The patient should know what to expect from the surgery and should understand the post-operative rehabilitation phases.

POSTOPERATIVE

Week 1

Ice and elevation are used regularly to reduce swelling. The goal is full extension and 70 degrees of flexion by the end of the first week. The use of knee pads and crutches is mandatory. Multiple mobilizations of the patella should be included for at least 8 weeks. Other mobilization exercises in the first 4 weeks are passive knee extension (no hyperextension) and passive and active mobilization towards flexion. Strengthening exercises can be done for the gastrocnemius, hamstrings, and quadriceps (vastus medialis).

– To reduce the risk of blood clots, aspirin is recommended for an adult (325 mg) twice a day. Special anticoagulants may be prescribed for some patients who are at higher risk of clotting.

– You can remove the knee immobilizer while exercising or if you are in a safe, protected environment. However, the knee immobilizer should also be worn for the first 2 weeks while sleeping and walking until the leg regains muscle control.

– Weight bearing status – This applies to any ACL reconfiguration unless stated otherwise.
1-7. Day = 50% body weight (2 crutches)
Days 8-14 = 50-75% of body weight (1 crutch)
can be prescribed.

– You can remove the knee immobilizer while exercising or if you are in a safe, protected environment. However, the knee immobilizer should also be worn for the first 2 weeks while sleeping and walking until the leg regains muscle control.

– Weight bearing status – This applies to any ACL reconfiguration unless stated otherwise.

At the end of week 2 = full weight bearing

– Early ROM and Extension

1) Passive extension of the knee using a rolled towel. The towel should be high enough to lift the calf and hip off the table.
• Remove the knee immobilizer from your knee every 2-3 hours while awake.
• Place the heel on a pillow or rolled blanket without the knee support.
• Let the knee come to full extension passively for 10 – 15 minutes. Relax your muscles and gravity will help your knee come to full extension.

2) Active assisted extension: It is performed using your opposite leg and quadriceps muscles to bring the knee from the 90 degree position to 0 degrees. Hyperextension should be avoided during this exercise.

– Passive flexion of the knee up to 90 degrees

• Sit on the edge of a bed or table and let gravity gently bend your knee.
• Used to support and control the amount of flexion of the opposite leg.
• This exercise should be done 4 to 6 times a day for 10 minutes.

– CPM

A CPM (Continuous Passive Motion) machine may be prescribed. It will be delivered within 24 hours and should be used 6-8 hours a day. Start at 0-45° and increase as tolerated until you reach 90°. This is used for 2 weeks, but if there is any cartilage treatment in the knee, the time can be extended.

– Quadriceps exercises

1. You should begin quadriceps isometric contractions as soon as possible in the knee full extension position.
   • Do 3 sets of 10 repetitions 3 times a day.
   • Each contraction should be held for 6 seconds.

2. Begin straight leg raises (SLR) in 3 sets of 10 repetitions 3 times a day with a knee immobilizer. Start doing these exercises while lying down.
   • This exercise is first performed by contracting the quadriceps while the leg is in full extension. Quadriceps contraction “locks” the knee and prevents excessive stress from being applied to the healing ACL graft.
   • The leg is then held straight and raised approximately 45-60 degrees and held for six seconds.
   • The leg is then slowly lowered onto the bed and the muscles are relaxed.

3. This exercise can be done outside of the corset when the leg can be kept straight without sagging. After gaining strength, straight leg exercises can be done while sitting.
   

– Hamstrings

For patients who have had ACL reconstruction using hamstring tendons, it is important to avoid excessive stretching of the hamstring muscles during the first 6 weeks after surgery. The hamstring muscles need about 6 weeks to heal, and excessive hamstring stretching during this time can cause the hamstring muscle to “pull” and increase pain. Unintentional hamstring strain often happens when you lean forward and try to put on your socks and shoes, or when you bend forward to pick up an object from the ground.

Week 2-4

The patient should try to increase the stance phase of walking with a single crutch. With good hamstring/quadriceps control, the use of crutches can be reduced sooner. If you have a return-to-work desk job, you can return to work when your pain relief needs decrease and you can safely walk on crutches. Typically this is between 10 and 12 days after surgery.

Continue full passive extension, gravity assisted and active flexion, active assisted extension, quadriceps isometric exercises, and straight leg raises.
Begin Partial Squat.

• Place feet shoulder-width apart in a slightly turned-out position.
• For stability, use a table and slowly lower the hip back and down.
• Hold for 6 seconds and repeat.
• Do 3 sets of 10 repetitions each day.

Begin Toe Raises.

• Using a table for stabilization, slowly lift the heel off the ground and balance on the toes.
• Hold for 6 seconds and slowly relax backwards.
• Do 3 sets of 10 repetitions each day.

If you have good muscle control in the leg, begin removing the knee immobilizer. After stopping the immobilizer, you should continue to use the crutches until you put full weight on your leg. You can start using a stationary bike when you can bend your knee at least 100 degrees. Cycling is an excellent conditioning exercise for the quadriceps.

Week 5

The use of knee pads is gradually reduced. Exercises should be started at light intensity (50% of maximum strength) and gradually increased to 60-70%. Exercise progress depends on pain, swelling and quadriceps control. If general strength is good, proprioception and coordination exercises can be started.

Week 10

By week 6, your range of motion should be fully extended to at least 135 degrees of flexion. Forward, backward and lateral dynamic movements as well as isokinetic exercises can be included.

3 Months

The patient can switch to functional exercises such as running and jumping after 3 months. The heavier the proprioceptive and coordination exercises, the faster changes in direction are possible. Straight, forward and straight, backward running and light jogging program should be started.

4-5 Months

The ultimate goal is to maximize the endurance and strength of the knee stabilizers, optimize neuromuscular control with plyometric exercises, and add sport-specific exercises. Variations in acceleration and deceleration, running and turning, and cutting maneuvers improve arthrokinetic reflexes to prevent new trauma during competition. This is the earliest time you should plan to return to full sport.

REFERENCES

1) Cavanaugh JT, Powers M. ACL Rehabilitation Progression: Where Are We Now?. Curr Rev Musculoskelet Med. 2017;10(3):289-296. doi:10.1007/s12178-017-9426-3

https://www.physio-pedia.com/Anterior_Cr…bilitation
https://www.sportsmednorth.com/sites/spo…otocol.pdf
https://www.ouh.nhs.uk/patient-guide/lea…210acl.pdf
https://www.totalphysiosydney.com.au/blo…on-program