What is the anterior cruciate ligament?

Its anatomical name is anterior cruciate ligament. Length is 38mm (4cm), width is 10mm (1cm) and it prevents anterior translation of the tibia and hyperextension of the knee. It also protects the knee against valgus stress and prevents external rotation of the knee (0-30), providing proprioception and mechanical stability in the knee.

The anterior cruciate ligament consists of 2 main bundles; anterior lateral and posterior medial.

While the anterior medial band is taut in flexion of the knee, the posterior-lateral band is loose, and it’s quite opposite in extension.

How does the anterior cruciate ligament injures?

Anterior cruciate ligament injuries can also be injured in situations such as sudden change of direction, shearing movement or touching the ground after jumping, sudden stopping, sudden weight transfer. The injury may accompany the medial lateral ligament and meniscus.

Types of anterior cruciate ligament injury:

Grade 1: It progresses with minimal ligament damage and pain.
Grade 2: More ligament damage and joint discharge are seen.
Grade 3: The ligament is completely torn and the joint is not stable.

Symptoms seen in anterior cruciate ligament injuries:

When the anterior cruciate ligament is torn, a popping sound can be heard from the knee. The injury is usually accompanied by pain and movement is not possible. After a few hours, the knee swells a lot and walking becomes difficult. Within two days, it becomes the worst and begins to subside.

To diagnose; anterior drawer test, lahman, pivot shift, KT 1000-2000 tests are performed and MRI of the knee to evaluate the condition or XR images are examined to examine the presence of injury in the bones.

Anterior cruciate ligament surgery:

Autograft or allograft can be used in surgery.

Autografts used;
Bone-tendon-bone grafts: They are the strongest grafts, but they disrupt the extension mechanism and cause a lot of anterior knee pain.
Hamstring grafts: It is the most preferred surgery in Turkey.
Quadriceps tendon grafts: These grafts also disrupt the extension mechanism and cause pain.

Allografts used;
Allografts are tissues used from cadavers. Allografts are Achilles tendon, hamstring tendon, tibialis posterior tendon and Quadriceps tendon.



  • Our main goal should be to provide full knee extension in anterior cruciate ligament rehabilitation. Because if we cannot achieve knee extension in 2 weeks, we cannot achieve the desired result again. Especially if hamstring graft is used, extension loss is more common. We can lift the leg up by placing a pillow under the heel to ensure extension. We can also do hamstring stretching carefully.
  • Loss of patellar mobility is more common when pattelar tendon is used. We should do patellar mobilization in all directions.
  • We must control pain and edema. Edema occurs in the quadriceps. We can use ice, compression bandages, NMES and ROM exercises to control edema.
  • We should increase the range of motion of the joint. For this, ROM exercises should be performed without forcing the patient too hard (we aim 90 degrees ROM for 0-7 days). Full ROM should be gained in 4-6 weeks.
  • Weight transfer and proprioception exercises should also be practiced in the early period.


Our criteria for transitioning to the early rehabilitation phase:

  • 90 degrees of knee flexion should be achieved.
  • Full patellar mobility should be achieved.
  • Full knee extension should be achieved.
  • Independent ambulation ability should be developed.

Our early rehabilitation phase (2-4 weeks) exercises:

  • Mini squat exercises should be started. (30-degree squat exercises.)
  • Leg press is one of the exercises that can be practiced.
  • We should work knee extension (last 0-30°) while sitting.
  • Lunge
  • Hip circumference strengthening and step exercises should be done.
  • Proprioception exercises should be added to the program.


Criteria for transition to controlled ambulation:

  • The patient should be able to perform 115° active knee flexion.
  • Isometric quadriceps strength should be 60% of the intact side.
  • KT test should be +1 less than the other side.

Controlled ambulation phase (4-10 weeks) exercises:

  • We continue with the other exercises.
  • Stepper should be worked.
  • Vertical squat should be done.(*We must be careful that the knee does not go into valgus while doing the exercises.)
  • Isokinetic exercises can be done.
  • We can move on to plyometric exercises for athletes.


Criteria for transition to advanced activity:

  • Isometric quadriceps strength should be 79% of the intact side.
  • Active ROM should be 125°.
  • The KT test should be the same as the other side.
  • The HOP test should be 80% of the other side.

Advanced activity phase (10-16 weeks) exercises:

  • Plyometric exercises are given importance in this phase where we work with athletes. (10th week is the transition phase to plyometric exercise).
  • 90°-40° isokinetic exercises


This phase is the phase in which it is decided that the athlete will return to sports by making appropriate evaluations for the athlete’s branch. The tests used in the evaluation of the athlete are run during this period and the decision is made with the final evaluation.


Criteria for the transition to the return to sports phase:

  • Full ROM must be provided.
  • Quadriceps strength should be 80% of the other side.
  • Hamstring strength should be the same as the unaffected side.
  • Biodex position sense should be the same as on the other side.
  • Athletes should feel psychologically ready.

*People who have had anterior cruciate ligament reconstruction usually return to sports within 6 months to 1 year after surgery.

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