The anterior cruciate ligament, also known as the ACL, is one of the major cruciate
ligaments that are located within the joints of the knee. The ACL provides stability to your
knees, along with preventing over-bending and over-straightening of the knee. The ligament
is connected between the tibia and femur. A torn ACL can refer to any injury caused to the
ligament. A number of different things can cause a town ACL, such as a twisting force
applied to the knee while the foot is firmly placed on the ground, or a direct blow to the
knee upon a landing.
ACL tears are one of the most common types of sports injuries, and can be mild to severe.
Sports that involve more physical contact than others, such as football or soccer are more
prone to causing ACL tears. ACL tears can also be received from non-contact sports related
injuries, like landing from a jump, running, pivoting, or overextending the knee joint.
ACL Tear Symptoms
Symptoms of an ACL tear will vary based on how severe the tear is, and whether or not more
injuries were received as a result of the original injury.
Pain – along with an ACL tear, there will be excruciating knee pain. It will begin
initially as a sharp pain on the outside and back of the knee, and then usually will become
a throbbing ache in the knee. Movements that involve the knee like straightening or bending
it will increase the amount of pain.
‘Pop’ sound – when the injury first occurs you could hear an audible ‘pop’ or cracking
sound. After this noise follows sharp pain in the knee.
Swelling – Swelling starts to occur almost immediately after the tear occurs. Also known
as hemarthrosis, this symptom is very common amongst ACL tears. The swelling is caused due
to disruption of the anterior cruciate ligament which causes the knee joint to fill with
blood. The swollen knee will appear tight and look puffy and large.
Loss of Strength and Instability – The ACL helps provide stability to your knees, so
when an injury occurs here the knee joints may become unstable. Minor tears may cause
instability while jumping or pivoting, while major ACL tears can cause difficulty moving
around and the knee will “give away”.
Limited Movement – Because the knee swells and has extreme pain, this will result in a
decreased range of movement in the knee and legs.