Dr. John M. Kunkel

ACL Surgery: Dr. John M. Kunkel

ACL Graft Choice:

Patient Education and Information

You are going to have your ACL surgically reconstructed.  The next choice is: what type of ACL graft should you have?

The first step in making this decision is choosing between autograft or allograft.

Autograft means that the graft tissue comes from your body. We take a tendon from your body and make it into your new ACL.

Allograft means that the graft tissue comes from a cadaver.  A donor tendon is taken from a cadaver and made into your new ACL.  The graft is processed in a way to minimize the risk of disease transmission – which makes that risk very low (HIV ~ 0.0006%, Hepatitis C ~ 0.0002%).8

One important advantage of autograft (your own tendon) is that it incorporates and heals more quickly; which means it becomes a functioning ACL earlier which allows a quicker return to sports and athletic activities.

The benefit of an allograft (donor tendon) is that we do not need to take a tendon from your own body, which means there is less postoperative pain and shorter surgical time.

The outcomes for allograft versus autograft are overall similar in patients over the age of 35 or 40 years old.  However, in younger patients, autograft (your own tendon) has lower re-rupture rates than allograft.1 

So, generally for younger (<40 years old) more active patients, we recommend using autograft (your own tendon) ACL reconstruction.

Autograft Options:

If you’ve chosen autograft (your own tendon) as the best option for your new ACL, now you need to choose which of your tendons to use to create your new ACL.  The 3 tendons that have been historically used most consistently are:

Patella Tendon (BTB), Quadricep Tendon, or Hamstring Tendon

Patella Tendon (Bone-Patella Tendon-Bone or BTB)

The patella tendon graft is commonly referred to as the “bone-patellar tendon-bone” graft or “BTB graft”.  The BTB graft has been the most popular tendon graft for ACL reconstruction over the last 30 years. 

To take the BTB graft, we take a piece of your patella (kneecap) and a piece of your tibia (shin bone) as well as a strip of your patella tendon between those two bone pieces which results in a piece of tendon with a bone piece on each end.

We then drill a tunnel in your femur bone where the ACL attaches and a tunnel in your tibia bone where your ACL attaches and then we place the bone pieces from the BTB graft into those tunnels which results in the tendon portion crossing the knee joint as the new ACL. 

Screws are then placed into the tunnels to fix the bone pieces and the new graft in place.

There are many benefits of using the BTB graft.  First, it has bone on either side of the tendon inside the bone tunnels which allows bone healing to bone after ACL construction.  Bone to bone healing occurs more quickly than soft tissue healing to bone.2  This allows for progression and acceleration of rehabilitation more quickly which is valuable in elite athletics.  Historically, there have also been studies showing lower re-rupture rates and better outcomes after BTB ACL reconstruction compared with soft tissue graft reconstruction.3  However, recent meta-analysis show that the re-rupture rates, while still slightly favoring BTB, are very similar amongst the available autografts.4  The downside of a BTB graft is that it does cause increased anterior knee pain at the site of graft harvest.  In most cases this usually resolves by the one-year mark from surgery.  However, it does often cause persistent kneeling discomfort, which may never resolve.  So, for people in professions that require kneeling, we would usually recommend other graft options to prevent this discomfort from interfering with their profession.  There is also a small risk of patella fracture (0.4-1.3%) or patella tendon rupture (0.18-0.25%).

Soft tissue Autograft options: Quadricep Tendon or Hamstring Tendon

Historically, hamstring tendon was very popular as it did not require an extra incision to harvest the hamstring graft and complete the ACL reconstruction. However, it may decrease hamstring strength, which is an important secondary stabilizer of the knee to anterior translation of the tibia.5  The hamstring graft can sometimes be inconsistent in size and the literature has shown an increased risk of re-rupture if the graft is less than 8 mm in width. 

Recently, due to advances in fixation technology and graft harvesting technology, the quadricep tendon has increased in popularity.  Some recent studies have shown that quadriceps tendon graft is superior to hamstring tendon graft with lower re-rupture rates.6  Other recent studies have even shown that quadriceps tendon graft may rival BTB graft in terms of overall outcomes and with less harvest site pain.7

My Practice Recommendations:

In my practice, if you are under the age of 40, I recommend an Autograft ACL reconstruction (your own tendon).  If you are over the age of 40, then we will discuss the possibility of allograft ACL reconstruction depending on your athletic demands.

If you have chosen autograft ACL reconstruction (your own tendon), my first choice in graft recommendation would be BTB Autograft.  However, if there are concerns about anterior knee pain or kneeling pain, then we will discuss soft tissue graft options.  Or, if you are young and have open growth plates, we may discuss soft tissue graft to prevent growth disturbances. 

If you have chosen soft tissue autograft, I primarily use Quadricep Tendon autograft given its superior outcomes and lower re-rupture rates seen in recent literature.  If there is a reason for which BTB autograft and Quadricep tendon autograft cannot be used, then I will use hamstring tendon autograft.

References:

  1. Barrett AM, Craft JA, Replogle WH, Hydrick JM, Barrett GR. Anterior cruciate ligament graft failure: a comparison of graft type based on age and Tegner activity level. Am J Sports Med. 2011 Oct;39(10):2194-8. Epub 2011 Jul 22. PMID: 21784999.
  2. Rodeo SA, Arnoczky SP, Torzilli PA, Hidaka C, Warren RF. Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog. J Bone Joint Surg Am. 1993 Dec;75(12):1795-803.      PMID: 8258550.
  3. Gifstad T, Foss OA, Engebretsen L, Lind M, Forssblad M, Albrektsen G, Drogset JO. Lower risk of revision with patellar tendon autografts compared with hamstring autografts: a registry study based on 45,998 primary ACL reconstructions in Scandinavia. Am J Sports Med. 2014 Oct;42(10):2319-28.             PMID: 25201444.
  4. Samuelsen BT, Webster KE, Johnson NR, Hewett TE, Krych AJ. Hamstring Autograft versus Patellar Tendon Autograft for ACL Reconstruction: Is There a Difference in Graft Failure Rate? A Meta-analysis of 47,613 Patients. Clin Orthop Relat Res. 2017 Oct;475(10):2459-2468.            PMID: 28205075
  5. Konrath JM, Vertullo CJ, Kennedy BA, Bush HS, Barrett RS, Lloyd DG. Morphologic Characteristics and Strength of the Hamstring Muscles Remain Altered at 2 Years After Use of a Hamstring Tendon Graft in Anterior Cruciate Ligament Reconstruction. Am J Sports Med. 2016 Oct;44(10):2589-2598. Epub 2016 Jul 18.           PMID: 27432052.
  6. Hurley ET, Mojica ES, Kanakamedala AC, Meislin RJ, Strauss EJ, Campbell KA, Alaia MJ. Quadriceps tendon has a lower re-rupture rate than hamstring tendon autograft for anterior cruciate ligament reconstruction – A meta-analysis. J ISAKOS. 2022 Apr;7(2):87-93. Epub 2021 Nov 17     PMID: 35543668.
  7. Mouarbes D, Menetrey J, Marot V, Courtot L, Berard E, Cavaignac E. Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Outcomes for Quadriceps Tendon Autograft Versus Bone-Patellar Tendon-Bone and Hamstring-Tendon Autografts. Am J Sports Med. 2019 Dec;47(14):3531-3540. Epub 2019 Feb 21. PMID: 30790526.
  8. Zou S, Dodd RY, Stramer SL, Strong DM; Tissue Safety Study Group. Probability of viremia with HBV, HCV, HIV, and HTLV among tissue donors in the United States. N Engl J Med. 2004 Aug 19;351(8):751-9. PMID: 15317888.