The Amazing ACL

With a total of roughly 250,000 ACL ruptures annually in the United States, it is time we begin to understand more about this important, yet easily misunderstood, ligament.

The ACL, or Anterior Cruciate Ligament, originates at the end of the femur (thigh bone) and inserts at the top portion of the tibia (shin bone). It has two major fiber bundles that combine to provide stability in the knee. The ACL is responsible for resisting anterior translation of the tibia (forward movement of the shin bone) and internal tibial rotation (torsional forces).

It is most injured in a non-contact mechanism. In fact, 70% of all ACL injuries are non-contact. This means that the ligament fails without any external force to cause the injury. This happens, most commonly, from a pivot, quick change in direction, or twisting of the knee.

The other mechanism of ACL injury can occur by means of contact, which most commonly happens when the knee goes into hyperextension with a direct blow to the joint. In both circumstances, the person will feel a “pop” in the knee which is due to the ACL tearing. There are many reasons the knee joint may “pop” that may not be of concern but are felt with ligamentous rupture most of the time when the injury occurs.

Generally, a person sustaining an ACL injury does not experience much pain or discomfort immediately, as adrenaline and protective mechanisms of the brain take over. However, in the circumstance of true ligamentous rupture, the knee will begin to swell, bruise, and become stiff over the next several hours. It may become more difficult to bear full weight through the joint, and most typically will be associated with feelings of instability, such as the knee “buckling” or “giving out.”

Unfortunately, ACL tears are very debilitating for the function and performance of the knee. It is likely that an athlete will be unable to participate in their sport at peak performance or without risking further injury to the knee. Time spent in rehab is typically 9+ months from the date of surgery and requires extensive effort, drive, and determination. However, with the motivation and encouragement in therapy, anyone can overcome this injury to safely return to sports, and/or do the things they love.

If you or someone you know is concerned about an injury to the ACL, it is best to schedule a visit to see your provider. There is non-invasive special testing that is sensitive and reliable to assess for ACL injury before you schedule any imaging.

If your therapist believes you have ruptured your ACL, they will explain your options and guide you in the next steps to start your journey of recovery. You will likely undergo magnetic resonance imaging, or MRI, to confirm your diagnosis while also assessing other anatomical structures within the knee that may be involved. From there, your goals and outlook will be discussed between your physical therapist, orthopedic surgeon, coach, parent, athletic trainer, etc. Collaboration is key, and your care should be individualized by an expert in ACL rehab and recovery.

Want to learn more about ACL rehabilitation? Stay tuned for more information in the future on what happens next following surgical reconstruction of the amazing ACL.

My daughter tore her ACL in September and started her post-op ACL Journey in November! Jacob has been great. He is very knowledgeable about the process! He is very kind and patient with her. He makes PT fun! He has been able to answer all questions thoroughly to my daughter’s understanding. We are almost 5 months post-op and the improvements from day one we have seen are remarkable! Kudos to Jacob, he is the best!

Written by: Jacob Davies, PT, DPT
Fayetteville, Arkansas