ACL Anatomy

Knee joint stability is provided by 4 main ligaments about the knee. Two cruciate ligaments are contained within the joint and two collateral ligaments are located outside of the joint (one on the inner knee (MCL) and one on the outer knee (LCL)). The ACL (anterior cruciate ligament) is a ligament that connects the femur (thigh bone) to the tibia (shin bone). It provides both rotational (twisting) and translational (sliding) stability to the knee joint.  The ligament is located within the knee joint.

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ACL Pathology

The ACL is susceptible to tearing with both contact and non-contact injuries.  Associated injuries include tearing of other ligaments (PCL, MCL, LCL), cartilage injuries and meniscal injuries. Appoximately 200,000 ACL injuries occur every year in the United State of America.  High-risk sports include soccer, football, basketball, skiing and lacrosse. A knee without an ACL is at risk for repeated buckling episodes. These buckling episodes can lead to irreparable damage to the cartilage of the knee.


In those patients with a high demand for knee rotational and translational stability, an ACL reconstruction may be indicated.  You surgeon should discuss graft types with you including the anatomic source of the graft and whether the graft is taken from your own tissue (autograft) or a donor tissue (allograft).


  • BTB (patellar bone patella tendon bone)
  • Hamstring
  • Quad Tendon


  • BTB autograft
  • Achilles Tendon
  • Hamstring
  • Tibialis Anterior/Posterior
With patella tendon (BTB) autograft.

Call Dr. Gibbs for an appointment in Salt Lake City, Park City or Tooele, Utah if you are concerned you have sustained an ACL tear.

ACL Tear Information FAQ’s:

How will I know if I have an ACL tear?

  • An ACL tear can occur as a result of a contact or a non-contact injury.  A certain percentage of patients will report hearing a pop. Often the injury will be accompanied by knee swelling and pain.

Why doesn’t an ACL tear heal on it’s own?

  • ACL tears, like many other intra-articular tendinous and ligamentous injuries, do not heal on their own.  The synovial fluid, produced by the knee, dissolves the blot clot that is formed when the ligament tears.

Do I need to have my ACL reconstructed?

  • The surgery to manage a tear of the ACL is considered a reconstruction. In a reconstruction, tissue is taken from a donor locations and placed into the knee to reconstruct the ACL. Historically, an ACL repair (where the two ends are sutured together) has not had tremendous success at recreating the function of the ACL.  Because of recent techniques and studies, an ACL repair may be a good option in certain populations.
  • Not everyone who tears their ACL needs to have it reconstructed.  Some patients may be candidates for a repair. Other patients may be candidates for nonoperative treatment. A discussion with your surgeon is the best way to know if operative or nonoperative treatment is best for you.

What graft type is best for me?

  • This is an important conversation to have with your surgeon.  Many factors influence graft selection including age, activities and surgeon comfort.  Most grafts have demonstrated good success in the right patient.  Your surgeon should explain to you the rationale for your graft selection as well as the pro’s and con’s of the graft types.
  • As a surgeon, my general preference is use a patient’s own patella tendon. The benefits of this graft are numerous. It has bone at both ends of the tendon which allow bony integration. It is reliably the same size every time I use it (unlike hamstring tendon graft). It is as strong as any other graft being utilized.  There is substantial scientific evidence for its use. Finally, I have the most experience using this graft. The downsides of using patella tendon for a graft is that a small percentage of patient experience pain in the front of their knees. I have not found this to be significant in my experience and I believe that the benefits of using the patella tendon outweigh the risks.

How should I pick a surgeon for my ACL tear?

External Websites:


National Library of Medicine

AAOS ACL Surgery Module*

AOSSM Video Player*