The anterior cruciate ligament (ACL) is a pair of cruciate ligaments in the human knee. They are also known as cruciform ligaments. The anterior cruciate ligament is the main of the four ligaments of the knee joint, and ACL provides 85% of the restraining force to anterior tibial displacement (30 -90 degrees) of knee flexion. Anterior cruciate ligament (ACL) is in the middle of the knee. It prevents shin bone from sliding out in front of the thigh bone.
One of the most frequent knee injuries is an anterior cruciate ligament tear or sprain. Athletes who take part in high demand sports like football, soccer, and basketball are more prone to injure their anterior cruciate ligaments. Depending on the ACL injury severity, treatment may combine rest and rehabilitation exercises to support you regain strength and stability or surgery to replace the torn ligament accompanied by rehabilitation.
ACL injury Causes
Nearly 80 percent of sports-related ACL tears are “non-contact” injuries. This implies that the injury happens without the contact of another athlete. Usually, ACL tears when pivoting or landing from a jump. The knee gives out from under the player when the ACL is torn.
Several studies imply that female athletes have a greater incidence of ACL injury than males in certain sports. They proposed that this is for differences in physical conditioning, muscular strength, and neuromuscular control. Other proposed causes include differences in the pelvis and lower extremity alignment, increased looseness in ligaments, and the effects of estrogen on ligament properties.
ACL injuries often occur with other injuries, such as an ACL tear often occurs along with tears to the MCL and the shock-absorbing cartilage in the knee joint (meniscus). Most ACL injuries occur in the middle of the ligament, or the ligament is pulled off the thigh bone. Most frequent causes of ACL tear-
- If get hit very hard on the side of the knee, such as during a football tackle.
- Overextend of the knee joint.
- Quickly stop & moving and transmute direction while running, landing from a jump, or turning.
- Basketball, soccer, football, and skiing are the common sports linked to ACL tears.

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Types of ACL Injury or Tears
- Grade 1 – The ligament is mildly damaged in a Grade 1. It has been slightly stretched, but still able to keep the knee joint stable.
- Grade 2 -A Grade 2 Sprain stretches the ligament to the point where it becomes loose, and describe an ACL that is stretched and partially torn.
- Grade 3 -Commonly referred to as a complete tear of the ligament. The ACL ligament split into two pieces, and the knee joint is unstable.
Symptoms of an ACL Injury or Tear
- A “pop” in the knee at the time of injury
- Tenderness along the joint line
- Swelling of the knee
- Discomfort while walking
- Inability to bear weight on the leg
- Loss of full range of motion
- Instability of the knee
Diagnosis of ACL Injury
Diagnosis
Diagnosis based on physical examination and patient history, that’s include symptoms and medical history.
During the examination, your physicians will check all the structures of the injured knee, and compare them to the non-injured knee.
Imaging Tests
Other tests help your physicians confirm your diagnosis include:
- X-rays- x-ray will not show any injury to the anterior cruciate ligament, x-rays can show the injury is associated with a broken bone.
- Magnetic Resonance Imaging (MRI) – provide better images of soft tissues like the anterior cruciate ligament.

Treatment of ACL Injury
Treatment for ACL tear will vary depending upon the patient’s condition & individual need. For instance, the athlete involved in agility sports will most likely require surgery to safely return to sports. The less active may be able to return to a quieter lifestyle without surgery.

Nonsurgical Treatment
A torn ACL does not heal without surgery. Although, nonsurgical treatment may be effective for patients who are elderly or have a very low activity level.
- Bracing– Your physicians may recommend a knee brace to protect the knee from instability.
- Physical therapy– when the swelling goes down, a careful rehabilitation program is started. Specific exercises will restore the function of the knee and strengthen the leg muscles that support knee joints.
Surgical Treatment
Surgical treatment is recommended for individuals with a grade 3 or complete ACL tear. Surgical options vary the type of ACL injury. Surgically repair the ACL tear and restore knee stability; the ligament must be reconstructed. Your physicians will replace your torn ligament with a tissue graft.
Grafts are often taken from the patellar tendon which in between the kneecap and the shinbone. Hamstring tendons of the thigh are also a common source of grafts. Sometimes the quadriceps tendon is used. Finally, the cadaver graft can be used.
Rehabilitation
Whether or not treatment involves surgery, rehabilitation plays a vital role in getting back to daily activities. A physical therapy program will help you regain knee strength and motion.
If you have surgery, the physical therapy first fixates on returning kineticism to the joint and circumventing muscles. This is followed by a reinforcing program designed to protect the new ligament. Strengthening exercises gradually increase the stress across the ligament. We aim the final phase of rehabilitation at the functional return for the athlete’s sport.