Knee injuries (ACL and PCL injury)


Sure you had heard about knee injuries among sport players such as football players. Sometimes knee injuries are secondary to accidents.

Let’s widen our base of knowledge……

Knee injuries

Anatomy of the knee joint

It is a hinge type of joints. It has 2 movements: flexion and extension, so it helps in walking and running.

Flexion of the knee is done by the quadriceps muscle, while the extension is obtained by the hamstring muscles.

The knee joint is an articulation between the distal end of the femur bone (bone of the thigh) namely femoral epicondyle, and the tibia (The medial bone of the leg) namely tibial plateau.

The interface of the knee is a sesamoid bone called patella.

The articular surface of both bones is covered by cartilage to prevent the bones from friction during movements of the knee.

The knee is surrounded by bursas i.e.: synovial sacs.

They work as cushions to prevent friction.

There are 4 ligaments to maintain the knee stability.

Anterior and posterior cruciate ligaments, medial and lateral collateral ligaments, above all are knee joint associated ligaments.

The 2 cruciate ligaments (ACL and PCL) form an X like structure inside the knee joint.

Each one of them is attached to the femur and tibia.

The medial and lateral collateral ligaments connect the femur above to the tibia and fibula down respectively.

Injuries to these ligaments are common and can cause significant morbidity.

Types of knee injuries

There are multiple forms of knee injuries, but we are going to highlight the most common types.

Ligamentous injuries:

The most common injured knee ligament is the anterior cruciate ligament.

Bone injuries:

Fracture of any of the joint bones. However, the patella is the most common fractured bone in the knee.

Meniscal injuries:

Meniscal tear are common. Meniscus is the cartilage covering the articulating surfaces of the knee joint.


It is loss of the normal alignment of the knee secondary to trauma.

Causes and mechanisms of knee injuries  

Here we are going to discuss ACL and PCL knee injuries in particular.

As mentioned above, the ACL is the most common knee ligament to be injured.

Most common activity to cause ACL injury is the sport activities, for instance soccer, football and basketball as well.

About 50% of ACL injuries are associated with other knee injury, such as meniscal injury.

However, PCL injury usually results from motor car accident.

Clinical picture of knee injuries

  • The patient feels pain and tenderness in the knee joint.
  • Click sound from the knee during its movement.
  • The patient feels “giving a way” of the knee i.e.: looseness.
  • He walks in a limping gait.
  • The patient is unable to bear weight on the affected limb because of pain.


The best imaging study is MRI knee. However, physicians ask for X-ray at first.

Treatment of knee injuries

There are several lines of treating cruciate ligaments.

Mild and moderate injuries are treated medically and heal spontaneously. However, it needs some measure such as:

  • The patient should rest of the knee joint, with raising the limb on a pillow.
  • Apply ice and cold foments on the affected knee.
  • Use Knee brace or compression of the injured knee by elastic bandage.
  • The physician may recommend intake of analgesics.

The physiotherapist will help you to fasten pain relieving and healing.

He will teach you specific stretching and strengthening exercises.

Sever injuries, on the contrary, needs surgical intervention.  

It is reserved to the sever tear of the ACL or PCL.

The surgeon will do a knee reconstructive surgery to replace the torn ligament by another ligament from the body of the patient.

How to prevent knee injuries?

You should always warm up before heavy exercises.

Everyone should do regular stretching and strengthening exercises.

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