When it comes to ACL reconstruction surgery, there are some options. If you have decided that surgery is the best option, we look at the options for reconstruction and assess the pros and cons.

Last week, we discussed your first decision after blowing out your knee. Surgery or no surgery? Perhaps you have decided to manage your rehabilitation conservatively. Excellent. Find a physical therapist you can trust and get after it!

Too often, we blindly accept the opinions of others – without considering our thoughts or needs. This statement is especially true in healthcare when patients automatically follow their doctors' recommendations without considering all options. If you have decided that surgery is the best option, here comes decision number two.

How can athletes make an informed decision if you don't have all the facts? The best graft option for you is drastically different than what's best for someone, depending on your age, goals, and lifestyle demands.

“A wise man makes his own decisions. An ignorant man follows the public opinion.” – Grantland Rice

Best ACL Graft Options for Athletes

When reconstructing the ACL, you have a couple of options. There are a few less conventional ideas/methods out there, as well as some super cool experimental trials, but it usually comes down to these ACL graft options:

1. Allograft

2. Hamstring tendon autograft

3. Patellar tendon bone-tendon-bone autograft

4. Quadriceps tendon autograft

Autografts Vs. Allographics

A quick Google search should clear up any confusion regarding the definition of "cadaver." as we know from previous posts on ACL basics, autografts are pieces of tissue from a different part of your body. Allografts, on the other hand, are composed of tissues from cadavers.

While tendons and ligaments are composed of similar tissue, they are different. Both autografts and allografts are typically made up of tendons that remodel over time, forming an ACL-like substitute. The ACL-like substitute often results in a stable knee, but osteoarthritis and other comorbidities can develop later on down the road due to additional damage at the time of injury or from decreased knee stability after surgery.

The odds of cartilage lesion increase by 1% each month that elapses after injury without surgical intervention. Unfortunately, that is the risk you take when electing to have surgery on your knee. It is also the risk you take when choosing not to have knee surgery.

Keep reading for the pros and cons of each ACL graft option.

Option 1: Allografts

Allografts usually comprise a strong tendon from a cadaver's lower extremity.

The achilles and patellar tendons are most frequently used, but we have also seen cases of anterior and posterior tibialis tendons. Surgeons often suggest allografts, as there is considerably less pain and no "donor site morbidity," meaning you don't have to rob Peter to pay Paul.

With autograft procedures, surgeons must compromise a previously uninjured part of your knee to repair the ACL, making things like highly extremely troublesome in the future. Additionally, allograft procedures require less operating room time so you might spare your insurance company some extra bucks.

Cons of Allografts

While these are all excellent pros to consider, athletes don't overlook the cons of Allografts. Anytime you introduce foreign tissue to your body, you risk the body launching an immune response degrading the tissue, or rejecting the graft. You might go through months of recovery to discover you can do it all over again.

Though very slight with today's technological advances, you also risk disease transmission. All graft donor sources are tested for diseases like HIV and bacterial infections, but the risk of acquiring such pathology remains (though minuscule). 

Additionally, allografts are devoid of living cells, so they take longer to heal than autografts. This statement is a common misconception in sports medicine, so I like to educate all my patients before they go under the knife. I don't usually like to tell people how to think, so I will let you come to your own conclusions and leave this small statistic.

In a recent study looking at patients under 18 with closed growth plates (is this you?), there were no significant differences in function, activity, or satisfaction between allograft and autograft groups. However, the allograft group had a failure rate 15 times greater than that of the autograft group, with all failures occurring within the first year after reconstruction.

Option 2: Hamstring Tendon Autograft

The hamstring autograft is another option you might consider. In this procedure, the surgeon makes a small incision over the top of your shin bone where the hamstring tendons attach (also known as per anserine, or "goose foot.”) The ends of your medial hamstrings are detached from the shin bone and harvested to make a graft. The semitendinosus and gracilis are long skinny tendons and lend themselves well to be made into either single-bundle or double-bundle grafts. 

Your native ACL has two distinct bundles; one (anteromedial) prevents translatory instability, while the other (posterolateral) prevents rotatory instability. While different surgeons advocate for different techniques, a collection of research states that there is no significant difference in functional measures or clinical evaluation between single and double-bundle techniques. Hamstring tendon grafts keep your knee extensor mechanism (quads) intact and are often considered less painful. In my personal experience, I had more bruising and increased pain levels with the hamstring graft, but that may be because I'm old and soft now.

Back to the facts: A native, uninjured ACL can withstand 2160 Newtons of force. A semitendinosus gracilis graft, on the other hand, can withstand 4140 Newtons of force! The tendons are readily available and grow back to the attachment site via the "lizard phenomenon" – something I had no idea existed until a recent conversation with Dr. Brian McKeon at Boston Out-patient Surgical Suites in Waltham.The hamstring autograft is another option you might consider. In this procedure, the surgeon makes a small incision over the top of your shin bone where the hamstring tendons attach (also known as per anserine, or "goose foot.”) The ends of your medial hamstrings are detached from the shin bone and harvested to make a graft. The semitendinosus and gracilis are long skinny tendons and lend themselves well to be made into either single-bundle or double-bundle grafts. 

Your native ACL has two distinct bundles; one (anteromedial) prevents translatory instability, while the other (posterolateral) prevents rotatory instability. While different surgeons advocate for different techniques, a collection of research states that there is no significant difference in functional measures or clinical evaluation between single and double-bundle techniques. Hamstring tendon grafts keep your knee extensor mechanism (quads) intact and are often considered less painful. In my personal experience, I had more bruising and increased pain levels with the hamstring graft, but that may be because I'm old and soft now.

Back to the facts: A native, uninjured ACL can withstand 2160 Newtons of force. A semitendinosus gracilis graft, on the other hand, can withstand 4140 Newtons of force! The tendons are readily available and grow back to the attachment site via the "lizard phenomenon" – something I had no idea existed until a recent conversation with Dr. Brian McKeon at Boston Out-patient Surgical Suites in Waltham.

I, like many, had previously thought that the detached hamstring tendons retracted up into the thigh and that this was why many patients possess knee flexion strength deficits to post hamstring ACL reconstruction Research has shown that a torque deficit in deep knee flexion is almost always present postoperatively in these patients, but the cause remains unclear.

That brings me to the first (and perhaps most influential) con. Based on where the hamstrings sit anatomically, they help prevent anterior translation of the tibia in the open kinetic chain and prevent liftoff of the medial femoral condyle during dynamic valgus. This means they assist the ACL and play a fundamental role in knee stability. So why would you want to decrease the strength of something that protects the ACL significantly? This is especially true when discussing quadriceps-dominant young female soccer players. As relative quadriceps strength increases and hamstring strength decreases, the risk of ACL tear goes up.

This may be why ACL reconstructions with hamstring autografts have a higher re-injury rate than some alternatives (*cough, patellar tendon, cough*). But if you have a hamstring autograft – don't panic! Hamstring and calf eccentrics all day! Find a qualified strength and conditioning professional or medical practitioner and bulk up your posterior chain.

Unlike the patellar tendon autograft, which involves bony integration, the hamstring graft requires soft tissue-to-bone healing. This typically takes a little bit longer and requires slower rehabilitation to ensure the protection of the graft. Other cons to the hamstring autograft include possible shortening of the tissue surrounding the posterior capsule of your knee, making terminal knee extension (straightening your leg fully) a little bit harder to achieve postoperatively.

Option 3: Patellar Tendon Bone-Tendon-Bone Autograft

The patellar tendon bone-tendon-bone autograft is currently considered the gold standard for ACL reconstruction options. The graft is taken from your patellar tendon (aka patellar ligament), which attaches your kneecap to your shin bone.

The surgeon will cut out the middle third of the tendon, along with a small piece of bone from your knee cap and shin bone. The surgeon will then drill tunnels into your shin and thigh bones and pull the graft through, connecting the two tunnels and plugging the ends with bone. This tissue will serve as a latticework for your new ACL to grow.

The patellar tendon can withstand up to 2977 Newtons of force and is approximately 174% stronger than your native ACL at the time of harvest! The ACL-like structure initially weakens, reaching its weakest and most vulnerable point in rehab at around 8-12 weeks post-op, but then re-vascularizes and increases in strength.

The patellar tendon bone-tendon-bone graft is easily accessible, possesses excellent strength, and has excellent long-term results reported in the literature. Numerous studies have shown that the re-tear rate for patellar tendon autografts is significantly less than that of hamstring autograft. The patellar tendon also allows for more aggressive rehab, as bone-to-bone healing is much faster than soft tissue-to-bone. However, clinicians should be aware of loading the knee past 60 degrees of closed-chain flexion for the first 6-8 weeks to avoid patellar tendon irritation.

Cons of Patellar Tendon

Along with its pros, the patellar tendon also has numerous cons. The patellar tendon is flat and does not easily allow the double-bundle technique mentioned above. There is also the risk of patellar fracture, tendon rupture, tendinitis, and excessive scar tissue that can lead to arthrofibrosis or other range-of-motion complications (i.e., cyclops lesion).

Perhaps most noticeable is the donor site morbidity we talked about earlier. Diffuse anterior knee pain is a common development with patellar tendon autografts and may present a challenge for athletes who must kneel or crawl for their occupation. In my opinion, the pros of this option heavily outweigh the cons.

Option 4: Quadriceps Tendon Autograft

Your last option is the quadriceps tendon autograft. While much less popular, many studies have shown that the quad tendon graft is as successful as the hamstring or patellar tendon autografts. Single-bundle ACL reconstructions with quad tendon autografts have shown equal muscle recovery and knee stability compared to hamstring tendon grafts.

Quad tendon grafts also result in less kneeling pain, graft site pain, and sensation loss, with similar anterior knee stability and subjective outcome measures, compared to patellar tendon autograft. The quad tendon autograft has nearly twice the size of the patellar tendon cross-sectional area and can withstand up to 2353 Newtons of force.

It is also readily available but is more technically demanding on the skillset of the orthopedic surgeon. Other cons include that a scar on the anterior thigh may be cosmetically unappealing and that there needs to be more research on long-term outcomes due to lack of popularity.

How to Choose The Best ACL-R Surgery Graft Option for You

So there it is. You have all of the pros and cons of ACL reconstruction surgery options in front of you. Now you must make the best possible decision for YOU. Are you an athlete? Does your sport require multidirectional stability? Is this your first ACL tear, or do you need a revision? Are you a quad-dominant female athlete? Are you looking to return to pain-free ambulation with normal functional mobility ASAP? Don't sell yourself short.

Have questions about ACL reconstruction options or allographs and autographs? Ask our Hudson, Massachusetts physical therapists! Discuss your options with your surgeon and actively participate in your healthcare. After all, you're the one who will be stuck with the outcome forever. 

References

1. Kondo E, Yasuda K, Azuma H,Tanabe Y, Yagi T. Prospective clinical comparisons of anatomic double-bundle versus single-bundle anterior cruciate ligament reconstruction procedures in 328 consecutive patients. Am J Sports Med. 2008;36(9):1675-1687.

2. Meredick R.B., Vance K.J., Appleby D., Lubowitz J.H. Outcome of single-bundle versus double-bundle reconstruction of the anterior cruciate ligament: A meta-analysis. Am J Sports Med. 2008;36:1414–1421.

3. Ellis HB, Matheny LM, Briggs KK, Pennock AT, Steadman JR. Outcomes and revision rate after bone-patellar tendon-bone allograft versus autograft anterior cruciate ligament reconstruction in patients aged 18 years or younger with closed physes. Arthroscopy. 2012;28(12):1819–1825.

4. Fink C, Herbort M, Abermann E, Hoser C. Minimally Invasive Harvest of a Quadriceps Tendon Graft With or Without a Bone Block. Arthroscopy Techniques. 2014;3(4):e509-e513. doi:10.1016/j.eats.2014.06.003.

5. Iriuchishima T, RyuK,Okano T, SurugaM,AizawaS, Fu FH. The evaluation of muscle recovery after anatomical singlebundle ACL reconstruction using a quadriceps autograft [published online April 7, 2016]. Knee Surg Sports Traumatol Arthrosc. doi:10.1007/s00167-016-4124-z.

6. Lund B, Nielsen T, Fauno P, Christiansen SE, Lind M. Is quadriceps tendon a better graft choice than patellar tendon? A prospective randomized study. Arthroscopy. 2014;30(5):593–598. doi: 10.1016/j.arthro.2014.01.012.

7. Maletis GB, Chen J, Inacio MC, Funahashi TT. Age-Related Risk Factors for Revision Anterior Cruciate Ligament Reconstruction: A Cohort Study of 21,304 Patients From the Kaiser Permanente Anterior Cruciate Ligament Registry. The American journal of sports medicine. 2016;44:331–336.

8. Papalia R, Franceschi F, D’Adamio S, Diaz Balzani L, Maffulli N, Denaro V. Hamstring Tendon Regeneration After Harvest for Anterior Cruciate Ligament Reconstruction: A Systematic Review. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2015;31(6):1169–1183.

9. Wnorowski D. ACL Reconstruction: Graft Choices. Retrieved from https://www.sosbones.com/news/acl-reconstruction-graft-choices/. Published March 23, 2015. Retrieved September 2, 2018.

10. Macrina L. What is the Best Graft Choice for ACL Reconstruction? Retrieved from https://www.mikereinold.com/what-is-the-best-graft-choice-for-acl-reconstruction/. Retrieved September 2, 2018.