What is an ACL?

Those 3 dreaded letters….ACL.  Every athlete fears hearing them but regrettably ACL injury is part of sporting activities. Thankfully techniques to repair and reconstruct the ACL have advanced considerably in the past few years and as such, our ability to return an athlete to sport has also.

ACL stands for anterior cruciate ligament. It is one of the four major ligaments in the knee and its job is to help stabilize the joint by keeping the tibia (shin bone) from sliding out in front of the femur (leg bone). The ACL runs through the center of the knee, from the front of the tibia to the back of the femur. Its anatomy is actually very complex and is made up of two synergist bundles.  This ligament forms half of an “X” in the knee, with the other half formed by the posterior cruciate ligament, or PCL. This “X” has the appearance of a cross – giving the ligaments their respective names: “the cruciates.” The PCL is larger and stronger than the ACL and not as susceptible to injury. Dr. Armando Vidal, complex knee surgeon serving Vail, Aspen and surrounding Denver Colorado communities, has extensive experience treating ACL and other ligament injuries in the knee.

ACL | Vail CO

How does the ACL become injured?

The ACL’s main function is to limit abnormal motion between the tibia and femur. From an athletic and functional perspective, it serves mainly a rotational role.  It has a very minimal and limited role with linear activities such as walking and cycling – but is critical to activities that require sudden starts or stops, cutting, pivoting, jumping and changing direction.   Therefore, ACL injuries are most commonly seen in athletes who participate in sports that require such movements.  Ball (football, soccer, basketball, lacrosse….), racquet, frisbee and snow sports are the main culprits.

ACL injuries can range in severity from a small sprain or stretching of the ligament, to a partial tear or a complete tear. If the ligament is stretched beyond its normal range, the tibia can slip out from under the femur. The strong, rope-like tissue of the ligament can then stretch, tear or break.

What are the symptoms of a torn ACL?

People who experience an anterior cruciate ligament injury often report the following symptoms:

  • Pain, often sudden and severe (often on the lateral – outside – part of the knee)
  • A popping sound often heard at the time of injury
  • Rapid onset of swelling
  • Limited range of motion
  • Knee instability – the knee feeling as it will collapse
  • Inability to stand or walk without pain and difficulty

I’ve heard that women are more likely to tear their ACLs than men.  Is this true?

Unfortunately, female athletes are 3-5 times more likely to have an ACL injury than men. The exact cause of this difference remains unclear but is likely to result from a myriad of different biological, biomechanical and physiologic factors.

The only clear factor that has been consistently shown to influence this difference is biomechanics.  This fact is undeniable.  This has two important features as it pertains to your injury.  First is how do we minimize the risk of a recurrent ACL tear (retear)?  Second, is how do we prevent or minimize the risk of tear in the other (contralateral) knee?  Our research has shown that your risk of tearing the ACL in the other knee is about 3% over the first 2 years after ACL injury.  Partnering with a surgeon like Dr. Vidal, who understands this is key to a successful career beyond ACL injury.   His focus is not just on the knee you had repaired but on your risk as a whole.  He will ensure that you are partnered with a therapist who will help address any underlying risk factors during your recovery and help keep you in the game.

How is a torn ACL diagnosed?

ACLs are diagnosed through careful history taking, physical examination and imaging.  Despite advancements in imaging, a good physical examination can diagnose these injuries 95% of the time.  Imaging (both X-Rays and MRI) are necessary to confirm the diagnosis and evaluate for associated injuries.  Cartilage injuries, meniscal injuries and other ligament injuries are commonly found concurrently with ACL injury.  Dr. Vidal and his team will review your MRI with you personally and discuss the significance of these findings and how they will impact your recovery and surgery.

Are there different types of an ACL injury?

Anterior Cruciate Ligament injuries occur over a continuum of injury.  Many people like to compartmentalize them into grades (Grade 1,2 and 3) but these grades are not very reliable or helpful in making treatment decisions.

Effectively, an ACL injury can be partial or complete.  Although many patients focus on the extent of a partial injury (20%, 50%, etc.), the most important concept is whether or not the ACL is functionally competent.  There are several factors that help us make that determination: symptoms, physical exam and certain imaging findings.  If an ACL is functionally incompetent, it generally will not recover and is treated like a complete ACL injury.

One interesting variant of ACL injury is an Anterior Tibial Spine Fracture (ATSF):  These injuries typically occur in adolescents where the ACL itself is not torn, but the bony attachment of the ligament to the tibia is pulled off. This injury is unique and requires experience and expertise to repair successfully.  Dr. Vidal has extensive experience with these injuries in the pediatric population and has published extensively on the outcomes of these injuries as well as typical ACL injuries in kids.

Can an ACL tear heal by itself?

In general, it is not felt that an ACL tear can spontaneously heal. On rare occasions this can occur, but it is very unlikely and is the exception not the rule.  In fact, ACL healing is so poor that most conventional surgical treatments focus on reconstructing (creating a new ligament) rather than trying to repair it.  In recent years there is renewed interest in direct arthroscopic ACL repair (particularly in young patients with certain injury patterns), but long-term results remain inconclusive.

How do you treat a torn ACL?

Non-Surgical Treatment:

Many ACL tears can be treated without surgery.  Considerations include:

  • Severity of the injury (partial vs complete)
  • Associated injuries (meniscal injury, etc.)
  • Athletic and fitness goals and desires

Surgical Treatment:

Injuries that result in compromise of the ACL’s function (complete and high grade partial) in patients who desire to return to ACL-dependent activities, typically require surgical treatment.  The gold standard for ACL surgery is ACL reconstruction (ACLR).  Dr. Vidal is skilled and highly experienced at performing ACL reconstruction and repair in athletes at all levels (recreational, collegiate and professional) and can help patients in Vail, Aspen and the surrounding Denver Colorado communities return to their sporting activities quickly.

I’ve read about a variety of different grafts for ACL reconstruction.  What is the right graft for me?

As noted above – the ACL has limited intrinsic healing capacity and as such, reconstruction is often necessary.  In order to perform a reconstruction, we need tissue to create a new ACL.  Broadly, tissue can either come from you (autograft) or from a donor (allograft):

  • Autograft reconstruction: Autograft is still considered the gold standard and is certainly preferable in high demand athletes who want their knee to perform at a high level.  Autografts have lower retear rates, lower reoperation rates, and better return to play.  The drawback is there is a “price to pay” for taking tissue from one part of the knee and moving it to another.  We call that “graft site morbidity”.  The particular graft site morbidity varies depending on the source of the graft.  The three options for autograft are:
    • Patella Tendon (often referred to as bone-tendon-bone or BTB)
    • Hamstring Tendon
    • Quadriceps Tendon

Choice of autograft is based on an individual basis

  • Allograft: tissue taken from a donor cadaver. These types of grafts offer the benefits of a faster initial recovery and lower surgical morbidity. However, this comes with a higher risk of re-rupture, especially in younger and higher demand patients. Allograft can be a very successful option for many athletes and similar to autografts, this choice is made on an individual basis and with shared decision making between you and Dr. Vidal

Dr. Vidal has very extensive experience with ACL surgery and recovery.  He has successfully managed thousands of patients of all levels with ACL injury and can discuss with you the best surgical option for your specific type of ACL reconstruction and repair.

I have read about some surgeons performing ACL repair and not reconstruction.  What is that all about?

ACL repair was the standard of care in the early 1980’s and prior.  This was before the wide acceptance and development of our modern arthroscopic techniques.  Understandably, our knowledge of ACL injury, response to surgery, and rehabilitation was primitive then, compared to our current state.  As a result, outcomes of repair were predictably poor in this era.   However, as our minimally invasive techniques have continued to improve and our understanding of the role of biologics has expanded, there is renewed interest in repair.  At the current time, there are certain injury patterns that may be amenable to repair. Long term outcomes are unclear – but it may be a consideration for certain patients.

How long does it take to recover after ACL reconstruction?

Each patient’s recovery time is a very individualized and depends a great deal on the amount of reconstruction required and a patient’s return to sport goals and timeline. In general, patients can expect to return to work or school in as little as 5 days. Physical therapy is started almost immediately after reconstruction and a careful rehabilitation plan is prescribed by Dr. Vidal. Many fitness activities can resume between 6-12 weeks after surgery.  Full return to sport is made as a joint decision between Dr. Vidal and your therapist.  High demand athletes must pass a “return to sport” test in order to be cleared.  Most of Dr. Vidal’s patients can return to their regular sports activities 7-9 months after surgery.

ACL Reconstruction Surgeon

Are you an athlete who participates in a sport that involve sudden directional changes, such as pivots and twists? If so, you may be at risk of developing an injury to the ACL. ACL damage can be repaired with or without surgery, depending on the severity of your particular injury. Complex knee surgeon, Doctor Armando Vidal, provides diagnosis, including the grade or severity of the injury, and treatment to patients in Vail, Aspen, and the surrounding Denver, Colorado communities who are experiencing knee pain due to an ACL injury. Contact Dr. Vidal’s team today!


The Steadman Clinic – Vail, CO
180 S Frontage Rd W
Vail, CO 81657

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Vail, CO 81657

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