• Randon Hall, MD

ACL (Anterior Cruciate Ligament) Injury


Anterior Cruciate Ligament Injury


Typically occurs as a non-contact injury with a planted foot on the ground. Many times the athlete is shifting directions, where the body is moving in one direction and the knee is moving in the opposite direction. Usually the athlete will report a "pop" or the sensation of the knee giving away.

ExaM & Evaluation

Athletes will typically have swelling and fluid over the entire knee, not just the inner aspect or outer aspect. The swelling can be described as "like a water balloon" or "like a grapefruit" and should be apparent within the first 24 hours of the injury. On examination, a Lachman Test can be performed to check the stability of the ACL ligament, which is demonstrated below. Many times an ACL tear is associated with other injuries, such as a meniscus tear or lateral collateral ligament tear. Although the diagnosis can be confidently made by physical exam, an MRI is generally accepted as the appropriate test to confirm the presence of an ACL tear.



In general, the recommendation for a complete ACL tear is to have a surgical reconstruction, although there are exceptions. There are several options regarding what type of repair is appropriate for the specific athlete. Considerations include the age of the athlete, as well as the intention to return to sports in the future.

Return & Sports Considerations

The data on return to play is ever-changing in regards to ACL reconstruction. In the past, the general goal for return back to full sports participation was reported between 6 to 9 months. However, recent data suggests that we should potentially be waiting 1 to 2 years for return back to full contact sports participation. The focus has shifted away from a fixed time toward the need to meet functional criteria before returning back to contact sports. An isolated ACL injury will cause significant strength, balance and functional deficits after reconstruction. An athlete should consider a functional assessment, testing such criteria as strength, agility and balance prior to return, even if they have met time criteria for return back to sports. Functional assessments can uncover muscle imbalance, weakness or improper movement patterns that can put an athlete at risk for re-injury.

Front View of Knee

Inside of Knee (Zoomed View)

ACL is Intact

The Lachman Test is one test to determine the laxity of the knee, which can suggest a torn ACL. Test is performed by holding the upper leg (femur) firmly while the lower leg (tibia) is pulled forward. The video depicts a firm end point during examination, indicating that the ACL is intact.

#knee #ACL


Copyright 2017 The Sports Source, LLC

Dr. Randon T. Hall

A sports medicine physician with a passion to educate. My mission is to provide clear, concise and up to date education to athletes and sports fans for a better understanding of sports related health issues.


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