ACL Tear Surgery: Controversies & Variations

ACL-mountaintop“There are many paths to the Mountain top”.  This famous Chinese proverb couldn’t be more true than it is in Sports Medicine. There are a number of very good ways to do any one thing. As a result, not all Sports Medicine surgeons agree on everything, particularly when it comes to ACL tear surgery.

Let’s take a closer look at some of the areas of disagreement…

ACL Tear Surgery: Controversies & Variations

  • Number of grafts and tunnels
  • Augmenting reconstruction with extraarticular procedure
  • Location of tunnels
  • Types of grafts

As you read more about ACL tear surgery, you will see these topics come up over and over.  Let’s take some time and go through each of these more closely.

Number of grafts and tunnels

You may hear about the “Double-Bundle” procedure.  There are variations to this technique. However, it always requires two tunnels in each bone and two grafts, one in each set of the tunnels.  The more commonly performed “Single-Bundle” procedure has only one set of tunnels and one graft.

Based on studies performed on cadavers in a lab, double-bundle procedures may restore stability patterns closer to normal than the more common single-bundle surgery might.  Unfortunately, at this time, there is no clear evidence of any benefit when performed in actual patients.  In fact, because more tunnels, grafts, implants and surgical time is required, it is possible that the clinical results could ultimately be found to be worse.

The orthopedic history is full of technologies and techniques that based on intuition or laboratory findings were initially felt to be superior. Yet later they were found to have no benefit, or even in some cases, poorer results than the procedures they were to replace (i.e. laser knee surgery, thermal capsulorrhaphy, metal on metal hip replacements, etc.).  This appears to potentially be the case with the “Double-Bundle” procedure. Over the last several years, this has become performed less and less and as of now, appears to be falling out of favor. As a result, I am not currently recommending double-bundle procedures to my patients.

Location of tunnels

Those who frequently perform ACL tear surgery are now performing more “anatomic” reconstructions.  That is, they are trying to put the graft attachments closer to where the native ACL attaches than is done earlier techniques. I agree with this philosophy and so I perform “anatomic” ACL tear surgery.

One of the existing issues with this concept, however, is that the grafts that we use are not the same size and shape as the ACL that we are replacing.  As a result, we are unable to mirror the attachment points exactly. So controversy exists as to where along these attachment points we should be making our tunnels.  The “jury” is still out.  However, we are likely closer to the correct spot than we have ever been.  Now we are simply trying to get it “perfect”.  So if your surgeon performs “anatomic” ACL tear surgery, you are likely better off than you would have been just a number of years ago.

Augmenting with extraarticular procedure

ACL deficiency not only leads to straight front to back instability, but also varying degrees of rotational instability.  The traditional ACL reconstructions primarily addressed the front to back issue but not the rotational one. In order to better address this deficiency, surgeons have moved to more anatomic procedures.  It is also why, some have investigated “Double Bundle” techniques.

In order to address this concern, others are promoting additional extraarticular procedures performed along with your ACL reconstruction.  Such procedures you may here about are a repair or replacement of the Anterolateral Ligament or a Lateral Extraarticular Tenodesis. These are performed at the same time as your ACL reconstruction. They require additional incisions on the side of your knee, and on occasion, an additional graft.

There is some biomechanical data that shows some additional benefit with these procedures. Likewise, there is some early clinical data that also shows that these may be helpful in some select cases. However, exactly when and if these are needed is not yet known.

Types of grafts

There are four potential grafts that may be used in ACL tear surgery.  They can be either autografts or allografts. Autografts come from the patient’s knee. Allografts come from donors who have previously died.  Like most things, each of the grafts have potential benefits and areas of concern.  Which graft is best is based on a weighing of these variables.

  1. Patellar Tendon (“BPB”) Autograft – Very good stabilizing graft. Long track record. Concerns for pain in front of knee when kneeling, fractures of the kneecap during and after surgery and early arthritis in the knee cap joint.
  2. Hamstring Autograft – Very good stabilizing graft (equal to patellar tendon with modern fixation techniques).  Concerns for mild hamstring weakness based on subtle findings seen in lab setting and possible higher failure rates in certain groups (ie. Petite, very active females).
  3. Quadriceps Tendon Autograft – Very good stabilizing graft. Largest of all the grafts. Used less than others  –> less track record but becoming much more popular.
  4. Allograft – Less surgical time and potentially less pain.  Concerns for low risk of passing disease from donor to patient and higher (3-5x) risk of failure of the graft with recurrent instability, particularly in younger patients (<40-45 years old)..

ACL Tear SurgeryMy Graft Preference

Because of the very high success rates throughout the orthopedic literature, stability levels equal to or surpassing other grafts and the low complication rates due to the graft, my graft of choice is an all-soft tissue autograft, either Hamstrings or Quadriceps.  I use patellar tendon grafts and even allografts in select cases, but find one of the all-soft tissue autografts to be an excellent graft in nearly all patients. I am wary of using an allograft for a first time, isolated ACL reconstruction (no other ligaments need to be addressed surgically), particularly in younger patients.  However, I might consider it in select patients (i.e. older, less active patient).

These are my thoughts and your surgeon may feel differently.  Don’t be worried, talk to them so you understand their thinking.  Oh, and remember  – “There are many paths to the Mountaintop – But the view is always the same“. You should be just fine!



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