The Anterior Cruciate ligament is one of the key ligaments of the knee joint. It gives a great contribution to knee stability by preventing the excessive tibia movement to forward direction. ACL injuries are really common among the players of football, Basketball, Rugby Athletic events. These injuries are varying from mild to severe according to the damage to the knee region. So, it is significant that you have sound knowledge of ACL injuries, Treatment for injury, and also ACL rehabilitation protocol.

What are Cruciate ligaments?

These are very thick and strong fibrous bands which create a strong bond between tibia and femur. These are highly important for the anteroposterior stability of knee joint. There are two main ligaments named as Anterior cruciate ligament and posterior cruciate ligament.

Anterior cruciate ligament starts from the anterior part of the intercondylar area of the tibia. Then this ligament goes upwards, backward, and laterally to connect with the medial surface of the lateral condyle of the femur.

Posterior cruciate ligament begins from the posterior part of the intercondylar area of the tibia, runs upwards, forwards, and medially. Then it attaches to the lateral surface of the medial condyle of the femur.

Mechanism of Injury

ACL injury is commonly occurring during contact sports like soccer when sudden stress is applied to the knee joint while the tibia is in contact with the ground. Mainly, there are two types of ACL injuries.

Non-contact ACL injury

The most common type of ACL injury is non-contact ACL injury (more than 70%). The injured person may hear a pop or crack sound at the movement of injury occurs. Non-contact ACL injuries are mainly occurring during pivoting maneuvers or landing from a jump. It is clear that females are more prone to get non-contact type than males according to studies. Dynamic knee valgus position including femoral adduction, knee abduction, and ankle inversion is really affecting the non-contact type ACL injuries.

Direct contact Or Indirect contact

Here, the ACL is damaged due to external force. Direct contact means the external force is applied to the knee directly. Indirect contact means the external force is applied to the trunk or lateral thigh region.

It is worth knowing the mechanism of injury in prepare a more effective ACL rehab

Risk factors for ACL injury

  • Extrinsic factors (playing surface and conditions, footwear)
  • Genetic factors (familial predisposition, Collagen polymorphisms)
  • Anatomic factors (narrow notch width, increased tibial slope)
  • Hormonal factors (variation in female sex hormone concentration)
  • Biomechanical and neuromuscular factors (jump-landing mechanics, trunk displacements)
  • Female gender
  • Prior ACL injury
  • Clinical features
  • Swelling of the knee
  • Decreased range of motion (Especially can’t go full extension of the knee)
  • Weight-bearing is poor.

Treatment Types

  1. Rehabilitation as first line treatment is followed by ACL reconstruction, then post-operative rehabilitation
  2. ACL reconstruction and post-operative rehabilitation as the first-line treatment
  3. Pre-operative rehabilitation is followed by ACL reconstruction and post-operative rehabilitation

Most of the studies suggest that surgical intervention is the best way of management for those who love to achieve a high functional level of their sports. Non-operative management has shown limited success.

Medical treatment

In most cases, Medical treatment is following the ACL rehabilitation protocol with pain management. After the acute stage management, a Qualified doctor will assess the patient and sometimes he decides to do surgery after considering various factors like his or her participation in sports, Involvement other ligaments to the injury

ACL reconstruction – Graft types

  • Autograft: Using hamstrings tendons or patella tendon, this is the most commonly used type
  • Allograft: taking tibialis posterior tendon, Achilles tendon, tibialis anterior tendon, peroneus longus tendon for grafting
  • Synthetic graft: this method is rarely used. Still at the developing stage

Physiotherapy Management

Acute stage

At this stage, we focus on regaining range of motion, strength, proprioception, and stability of the knee joint. LOVE or PEACE protocol is used to protect knee with knee immobilizer and crutches for initial weeks until regaining good muscular strength. Practicing Ankle movements such as dorsiflexion, plantarflexion is also recommended during this stage. Knee range of motion exercises is also being performed in a sitting position. The physical therapists also recommend you Isometric exercises and patella mobilization exercises.

Pre-operative management

Post-operative management

Post-operative phase 1 (weeks 0-2)


  • Gaining full passive extension
  • Control post-operative swelling
  • Range of motion up to 900
  • Early progressive weight bearing


Pain and swelling are common symptoms after surgery. Cryotherapy, Elevation, and compression can be used to reduce swelling and pain. It is important to continue the rehabilitation program more effectively.

The physical therapist wants to do Quadriceps re-education by isometric quad strengthening exercises. As well as Patella mobilization exercises. From this phase, the patient should start Weight-bearing practice using a knee brace and crutches. Straight leg raises exercise (SLR) is playing a key role in ACL rehab protocol

Post-operative phase 2 (weeks 2-6)


  • Range of motion up to 1300
  • Good patella mobility
  • Minimal swelling
  • Restore normal gait


To achieve the above goals physical therapists will train patients to Progressive weight-bearing with crutches and knee braces. During this phase, Standard ergometry is also used. The patient should perform an Active assisted range of motion exercises. Then Mini squats, Straight leg raise exercises with progressive resistance are also performed. Proprioception training is another aspect of the phase 2 treatment plan.

Post-operative phase 3 (weeks 6-14)


  • Restore full Range of motion
  • Ability to descend 8” stairs with good leg control without pain
  • Improve lower extremity flexibility
  • Protect patella-femoral joint


  • Progress squat program
  • Initiate step-down program
  • Closed chain exercises (bike, leg presses)
  • Advanced proprioception training
  • Quadriceps stretching exercises

Post-operative phase 4 (weeks 14-22)


  • Demonstrate ability to run pain-free
  • Maximize strength and flexibility to meet the demands of activities of daily living


  • Start forward running (treadmill) program when 8” step down satisfactory
  • Continue leg strengthening and flexibility programs
  • Sports specific advanced agility program
  • Isokinetic knee extension exercises

Post-operative phase 5 (weeks 22-return to sport)


  • Lack of apprehension with sport specific movements
  • Maximize strength and flexibility as to meet demands of individual’s sport activity


During the final phase of ACL rehabilitation protocol, continue the advanced leg strengthening, flexibility and agility programs and also advanced plyometric exercises to enhance neuro muscular control.

Physical therapist encourage compliance to home therapeutic exercise program.

Patient should be done quality movement assessment at 6 months.


Before returning back to the sport, the patient should be advised not to give 100% of his performance until 9 months after the surgery. It is compulsory to prevent from further ACL

Credits for featured image : Image by planet_fox from Pixabay

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