Graft Choices and Outcomes in Anterior Cruciate Ligament Reconstruction:
A Guide for Physical Therapy Students
Laura Rapp, SPT
Background
During my clinical rotation in outpatient orthopedics, I encountered many young female athletes – mostly soccer players – who suffered from ACL tears and subsequent reconstruction surgeries. Out of curiosity, I often asked them whether they had used their own tendon for the graft repair or a cadaver graft. Although it appeared to me that there was a fairly even distribution of both allograft and autograft patients, one of the patients I worked with extensively had received an allograft and subsequently re-tore her ACL in return to sport only a year later. Following her re-injury, a screw was surgically placed in her knee in order prevent another re-injury, and she was told her soccer career was over. I became curious as to the incidence of graft failure and long-term outcomes in allografts versus autografts, and therefore I began to investigate the evidence for autograft versus allograft in preventing re-injury of the ACL. Although I assumed an allograft reconstruction may allow for quicker return to sport considering there is only one surgical incision being made, there may be a decreased chance of re-injury in return to sport using an autograft since it is the patient’s own healthy tissue being utilized. Although ACL reconstruction was covered in our physical therapy coursework, there was not a great deal of information on specific grafts and how they may affect the rehabilitation process following ACL reconstruction. By exploring the evidence surrounding this issue, one would gain a better understanding of graft choices for both athletes and non-athletes. This newfound information would additionally play an important role in informing patients when they go in for ACL surgery what to expect from rehabilitation while likewise assisting physical therapy students in better understanding the specifics of ACL tears, reconstruction, and rehabilitation.
Overview
Injuries to the anterior cruciate ligament are among some of the most commonly studied musculoskeletal injuries in health care today1. From 1994 to 2006, the number of patients who underwent an ACL reconstruction rose by about 33%, particularly in females1. Although surgeon preference dictates the type of reconstruction and graft choice utilized2, evidence shows that about 5-6% of individuals will have a subsequent graft rupture following ACL reconstruction, with those odds increasing six-fold for patients younger than twenty years.3,4 In addition, a patient returning to cutting or pivoting sports have even further increased risks of graft rupture by a factor of nearly four, with some studies reporting that approximately one in every nine patients undergoing ACL reconstruction will have re-rupture or clinical graft failure at long-term follow-up.3,5 Due to the fact that these odds for re-injury tend to be so high, it is imperative that surgeons, physical therapy students, and patients are informed of the best graft choices for their desired outcomes and how the graft may affect their rehabilitation process and ultimate return to function.
Therefore, the purpose of this capstone presentation is to provide DPT students with a comprehensive look at the anatomy and biomechanics of the ACL, the common mechanisms of ACL injury, clinical tests for ACL insufficiency, and descriptions of the common graft options for reconstructive surgery along with their association outcomes following post-ACL reconstruction rehabilitation.
Project Development and Products
My initial examination of this topic occurred during our Evidence-Based Practice II course during the fall of 2014. I developed a focused clinical question (i.e. a PICO question) investigating whether ACL reconstruction surgery utilizing an allograft effectively prevents re-injury after return to sport versus ACL reconstruction surgery utilizing an autograft. From this focused clinical question, I developed a Critically Appraised Topic to provide an in-depth analysis of some of the studies that provided the most relevant and high-level evidence on the subject. This allowed me to focus my topic and begin to further investigate the outcomes of allografts versus autografts following ACL reconstruction.
Following EBP II, I compiled an evidence table of recently published literature in order to provide a brief look at some of the latest studies investigating the long-term outcomes of utilizing allografts versus autografts in a wide variety of populations. This allowed me to easily organize the evidence and have a snapshot of the general findings in the literature to date.
Finally, I collaborated with a fellow classmate, Reid Medlin, in order to create the main product of my capstone – a VoiceThread presentation. Reid was working on a similar topic comparing hamstring autografts versus bone-patellar-tendon-bone autografts in terms of knee stability following ACL reconstruction. By collaborating in the final VoiceThread presentation, we were able to work together to create a comprehensive presentation designed to better prepare current DPT students going out on clinical rotations on questions regarding the ACL and outcomes associated with different grafts. To see more about Reid Medlin’s information on hamstring tendon autografts versus bone-patellar-tendon-bone autografts, click here!
Evaluation and Reflection
The VoiceThread capstone presentation is geared towards physical therapy students who are currently completing their Musculoskeletal II course; however, having access to the information provided may be beneficial to first year students out on clinical rotation as well. At the conclusion of the VoiceThread presentation, students who have viewed the VoiceThread are directed to complete a brief survey in order to provide us with feedback and comments on the presentation and material.
Throughout the process of researching, developing, and completing this capstone, I had a number of opportunities to reflect on my skills and the progress I was making. It quickly became apparent that timelines can rarely be set in stone, and flexibility along with consistent work is essential to prevent frustration and still accomplish the set goals. In addition, I learned new presentation skills and formatting in order to allow for individuals to get as much out of a VoiceThread presentation as possible without losing interest or feeling overwhelmed by information. For more information about presentation skills and what I learned in terms of general guidelines, click here. Furthermore, because I collaborated with a fellow classmate in the creation of the VoiceThread presentation portion of this capstone, I was able to bolster not only my teamwork and cooperation skills but also improve upon my communication skills.
Acknowledgements
I would like to give huge thanks to my committee members Jon Hacke and Marley Burns, and my capstone advisor Mike Gross, for their advice and feedback along the way. (In addition, an extra-special THANK YOU to Marley for providing such good feedback even on the week of her wedding!) Furthermore, I also appreciate the support and advice offered by Karen McCulloch in the development of this capstone project. And last but not least, I owe a massive thanks to my classmate and friend, Reid Medlin, for being a sounding board for ideas, a support system when I started panicking over deadlines, and more often than not, my voice of reason throughout this semester.
References
- Smith MA, Smith WT, Kosko P. Anterior cruciate ligament tears: reconstruction and rehabilitation. Orthop Nurs. 2014 Jan-Feb;33(1):14-24; quiz 25-6. doi: 10.1097/NOR.0000000000000019.
- Mall NA, Chalmers PN, Moric M, Tanaka MJ, Cole BJ, Bach BR Jr, Paletta GA Jr. Incidence and trends of anterior cruciate ligament reconstruction in the United States. Am J Sports Med. 2014 Oct;42(10):2363-70. doi: 10.1177/0363546514542796. Epub 2014 Aug 1.
- Webster KE, Feller JA, Leigh WB, Richmond AK. Younger patients are at increased risk for graft rupture and contralateral injury after anterior cruciate ligament reconstruction. Am J Sports Med. 2014 Mar;42(3):641-7. doi: 10.1177/0363546513517540. Epub 2014 Jan 22.
- Salmon L, Russell V, Musgrove T, Pinczewski L, Refshauge K. Incidence and risk factors for graft rupture and contralateral rupture after anterior cruciate ligament reconstruction. Arthroscopy. 2005 Aug;21(8):948-57.
- Crawford SN, Waterman BR, Lubowitz JH. Long-term failure of anterior cruciate ligament reconstruction. Arthroscopy. 2013 Sep;29(9):1566-71. doi: 10.1016/j.arthro.2013.04.014. Epub 2013 Jun 29.
3 Responses to “Graft Choices and Outcomes in Anterior Cruciate Ligament Reconstruction: A Guide for Physical Therapy Students”
Michael Gross
Laura- you and Reid did a very nice job on the Voicethread. Your CAT and evidence tables worked nicely in helping you prior to tackling the capstone project. I will repeat some of the same feedback I gave to Reid on his capstone site. You all really did not explain the basis for some of the risk factors such as antetorsion (you did mean antetorsion and not anteversion?) of the femur (you said hip in the presentation). Also, you did not explain how shoes and field surface might be risk factors for ACL injury. The next time you see me, ask me to demonstrate better technique for performing the Lachman’s Test. I also wonder how you could perform transverse friction massage on a reconstructed ACL. The section you all had on rehab protocols and progression was very light.
All in all, you and Reiddid a nice job on the Voicethread and you had other good components for your capstone.
Best regards, Mike
Laura Rapp
Mae,
Thank you so much for your comments! You make such a great point about the use of tendons as opposed to ligaments as the allografts FOR ligaments! I am also curious as to why an actual ACL allograft would not be used to replace a torn ACL. It makes sense particularly in light of the collagen orientation, as you mentioned. In thinking about it further, bone-patellar-tendon-bone grafts that are used for ACL reconstructions actually take part of the bony attachment in order to ensure that the graft incorporation is as strong as possible. It seems to me that if an ACL allograft were harvested from a cadaver, the surgeon could actually take part of the femoral and tibial bony attachments that are calcified (and thereby essentially “dead tissue” like the ligament itself) and insert them into the femoral and tibial tunnels of the patient for faster incorporation. I would not expect there to be implications in terms of graft-host rejection unless living bony tissue were taken, although I’m not positive. Nevertheless, you made an excellent point. I looked into it online to see if I could find any information about using ligament allografts rather than tendon allografts, but the American Academy of Orthopedic Surgeons list only patellar tendon, Achilles tendon, semitendinosus, tibialis anterior, tibialis posterior, peroneus longus, and iliotibial band allografts (http://www.aaos.org/news/aaosnow/apr12/cover1.asp). They don’t mention a rationale for why only tendons are utilized.
I will certainly keep looking into it and let you know if I find anything!
Thanks again, Mae!!
Laura
Mae Langford
Hi Laura!
Your (and Reid’s) VoiceThread presentation is really great! I thought you both spoke with great energy, which helped me as a viewer maintain my focus on your information. You also did a great job utilizing the drawing feature when discussing diagrams and pictures which really helped me hone in on the area you were discussing. Additionally, I was extremely impressed with the clarity of your explanations of the biomechanics and tissue properties. You were able to make the more challenging concepts easy to understand without watering down the content. Great job!
I think your suggestion that physical therapists must have knowledge to field patient questions is extremely important especially for patients who may have come to a therapist through direct access. If a patient suspects a torn ACL and asks the therapist to confirm, there will likely be questions about surgical options following the exam. I also think you did a great job explaining the therapist role throughout the injury process both in exam and in rehabilitation.
I was extremely interested in the description of the difference in tissue make-up between tendons and ligaments. The explanation of the direction of collagen fibers and how they provide unidirectional or multidirectional healing was extremely helpful to hear when thinking about which type of graft to choose. I am curious to know why surgeons do not seek out an ACL allograft for patients. Based on your description of the tendon collagen make-up, I would have expected the use of cadaver ligaments rather than cadaver tendons. I would expect the findings that irradiated tendons have reduced stability compared to non-irradiated tendons. However, I wonder if irradiated cadaver ACLs would better resist multi-directional stress compared to irradiated tendons because of the collagen direction and if those would be a viable option compared to autografts.
Thanks for an awesome presentation!
Mae