Anterior and Posterior Cruciate Ligament Injuries

Feature | Anterior and Posterior Cruciate Ligament Injuries | anterior cruciate ligament injury symptoms

 An ACL or PCL tear is often caused by high trauma events, like car accidents. Anterior and posterior cruciate ligaments are important to the stability of the knee joint. They make the joint stable and yet are configured in such a way as to allow for more than 90 degrees of flexion of the knee. Do you think you pulled a knee ligament and are not sure what to do? Keep reading to learn all about the anatomy, symptoms, diagnosis, and possible treatments for your knee ligament injury.ACL/PCL Tear | A Knee Ligaments GuideIn this article:Anatomy of Your Knee LigamentsAnatomy of Your Knee Ligaments | Anterior and Posterior Cruciate Ligament Injuries | anterior and posterior cruciate ligaments of knee joint

The knee is one of the complex joints in the human body. It connects the femur (or the thigh bone) to the tibia (or the fibula) in the lower leg with the fibula lying along its lateral side. It is connected together with four ligaments. The medial and lateral collateral ligaments prevent side-to-side motion of the femur across the tibia.

The anterior and posterior cruciate ligaments are complex. The anterior cruciate ligament starts in the anterior aspect of the tibia in the joint space and goes up to the back of the joint space on the femur. It crisscrosses the posterior cruciate ligament that starts in the posterior aspect of the tibial joint space and ends in the anterior aspect of the femur.

The anterior cruciate ligament (ACL) prevents the tibia from sliding forward along the femur, while the posterior cruciate ligament (PCL) prevents the tibia and femur from sliding towards each other.Injuries on the Anterior and Posterior Cruciate Ligaments of the Knee JointBoth the anterior and posterior cruciate ligaments are prone to spraining or tearing. These are primarily due to sports-related injuries, falls, and motor vehicle accidents.

About half of all damaging injuries to the ACL happen at the same time as damage to the articular cartilage, other ligaments, or the menisci of the knee. Injuries to the ligaments in the knee are graded according to their severity:
  • Grade 1 Sprain: This involves a ligament that has become slightly stretched, but the knee is technically stable
  • Grade 2 Sprains: The ligament has become loose or has become partially torn
  • Grade 3 Sprains: This is when the ligament has completely torn, leaving the joint completely unstable. It is rare to have a partial tear of the ACL. Most injuries of the ACL involve complete tears
Posterior cruciate ligament tears happen when the knee is in a bent position. This can happen in a sports-related injury, or in situations where a seated person strikes the dashboard with the bent knee.

Posterior cruciate ligament tears involve the exact grades noted above with ACL ligamentous injuries. One big difference between a PCL and ACL tear is that a PCL tear is usually only a partial tear whereas an ACL tear is usually complete.Cruciate Ligament Tear Symptoms: ACL and PCLWhen you get an injury to the anterior cruciate ligament or the posterior cruciate ligament, there are slightly different symptoms:
Anterior Cruciate Ligament Injury Symptoms
  • Pain in the knee
  • Swelling, which builds up over twenty-four hours
  • Loss of complete range of motion of the knee
  • Tenderness to palpation of the joint line
  • Pain and inability to walk on the affected leg
  • Unstable knee
Posterior Cruciate Ligament Injury Symptoms
  • Pain in the knee
  • Immediate swelling of the knee
  • Difficulty or impossibility of walking on the affected leg
  • The knee feels like it is going to “give out”
Causes of Knee Ligament InjuryThe causes of an ACL injury and a PCL sprain are slightly different. Here are some examples of possible causes of an ACL or PCL tear:
ACL Injury Causes
  • Automobile accident
  • Changing direction quickly, as in football or soccer
  • Stopping running quickly or suddenly
  • Running and slowing down rapidly
  • Landing a jump the wrong way
  • A football tackle with a direct collision
According to research, female athletes have a higher risk of ACL sprain than male athletes (depending on the sport). It is said to be due to differences in muscular strength, neuromuscular control, and physical conditioning. Some people feel the difference is due to changes in the shape of the pelvis and in the lower extremity alignment that makes women have looser ACLs in the first place. Estrogen also has an effect on the properties of the ligaments.
PCL Injury Causes
It usually takes a great amount of force to injure the posterior cruciate ligament, which can happen in the following ways:
  • A direct blow to the bent knee in an automobile injury
  • A sports-related injury in which the knee bends
  • Pulling on the ligament in a twisting injury or hyperextension
  • A misstep on uneven terrain
Diagnosis of ACL and PCL InjuryThe doctor will evaluate your ACL/PCL tear injury by checking for knee instability while comparing the findings to the uninjured knee. In PCL injuries, the knee will sag backward when bent. In addition, it can slide further back when the knee bends at greater than a 90-degree angle. X-rays cannot show the actual ligament but can reveal if the ligament has torn off a piece of the bone at the time of the injury. Such an event is called having an “avulsion fracture” of bone.

An MRI is the best way to assess ligamentous injury in the knee joint. It uses radio waves and a strong magnet to visualize bones and soft tissues. If the injury is at least 3 months old, however, it may not show up on MRI scanning.Natural Treatment of ACL and PCL InjuryThe best treatment for an anterior cruciate ligament tear depends on the person’s needs. Athletes usually want to get back into sports. Older people may just want to be able to return to normal activities without problems.

The treatment of an ACL sprain can be nonsurgical or surgical. A torn anterior cruciate ligament does not heal without having surgery on it. Even so, people with a low activity level or people who are elderly can tolerate having their ACL torn if the joint is basically stable. The doctor might recommend a knee brace to enhance the stability of the knee. Crutches or a walker limits the amount of weight bearing on the affected leg.

If the swelling goes down, a program of careful rehab is recommended with exercises that strengthen the muscles around the knee. Physical therapy can take a few weeks up to a few months.

When treating the posterior cruciate ligament, it is fortunate that many injuries heal without surgery. Rest, ice, compression, and elevation can be good enough when it comes to treating the PCL. The doctor may then recommend a knee immobilizer to prevent knee movement. Crutches or a walker helps prevent putting too much weight on the knee.Surgical Treatment of ACL/PCL Tear InjurySurgical Treatment of ACL/PCL Tear Injury| Anterior and Posterior Cruciate Ligament Injuries | acl pcl knee

Surgical treatment is the definitive way to heal an ACL joint. In general, the ACL joint can’t simply be stitched together. Usually, the surgeon will use a tissue graft on the ligament that acts as a scaffold for the new ligament to grow back onto. Grafts can be taken from the patellar tendon, from the hamstring tendon, or from a donor tissue.

Even with this kind of repair, it can be many months before the tendon is strong enough to be able to be used fully.

The procedure is usually done arthroscopically. It is less invasive than normal surgery, and the individual heals faster from the procedure. It is usually delayed to allow the inflammation of the tendon to heal. If you repair the ACL ligament too early, there is an increase in scar formation of the joint. This can limit knee mobility over the long haul.

Doctors recommend surgical treatment if there are multiple injuries inside the knee. Usually, the knee is very unstable at that point and needs many aspects treated surgically. As with the ACL sprain, doctors use a tissue graft to rebuild the ligament with scaffolding. The graft comes from another body area or from a cadaver.

The procedure uses an arthroscope with small incisions in the skin. As time goes by, medical practitioners develop better procedures to repair the posterior cruciate ligament.Rehabilitation of Cruciate Ligament RepairRehabilitation is needed for an ACL/PCL tear and is used both with and without surgical intervention. Physical therapy increases the mobility and strength of the knee. It usually begins 1 to 4 weeks after surgery. Physical therapy can last several months, and it can take 6-12 months for full recovery. The final aspect of rehabilitation focuses on the athlete’s functional return to sports.Complications of Cruciate Ligament RepairThe complications of cruciate ligament tears are about the same if it is an ACL tear or a PCL tear. These complications include:
  • Neurovascular injury
  • Osteonecrosis
  • Laxity that doesn’t go away
  • Loss of motion of the knee
  • Long-standing knee pain
Watch this video from Physical Therapy Video to learn about the top 3 signs of an ACL tear:


ACL and PCL injuries are caused by high trauma events, such as car accidents. Whether you've suffered from an ACL or PCL injury, it's still important to get your knee checked right away because the complications are just about the same for either injury. If you've been injured in an auto accident, call an experienced personal injury attorney to receive free and friendly advice concerning your situation.

Are you suffering from an ACL/PCL injury due to an auto accident? Reach out to us if you need more information or would like to know about your legal options. 

If you have been injured in an accident, please call me for free and friendly advice at 916-921-6400 or 800-404-5400. 

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Editor's Note: This post has been updated for quality and relevancy.
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