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
  • 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 poorer results than the procedures they were to replace (i.e. laser knee surgery, thermal capsulorrhaphy, metal on metal hip replacements, etc.).  For this reason, I have chosen to wait until clinical benefit is proven before 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.

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.
  3. 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).
  4. Quadriceps tendon Autograft – Good stabilizing graft.  Used much less than others  –> less track record.  Concerns for risk of knee cap fracture.

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 the Hamstring Autograft.  I use patellar tendon grafts and even allografts in select cases, but find the hamstring tendon graft to be an excellent choice 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 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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