Grafting for Anterior Cruciate Ligament Repair

The Anterior Cruciate Ligament (ACL) is one of the key knee structures that serves as a primary prevention for anterior tibia displacement (1). ACL repair is one of the most common sports injuries that often requires extensive physical therapy and, in some instances, surgical intervention. Surgical ACL reconstruction is needed when the damage is too extensive to allow for non-surgical repair or if patients intend on returning to their vigorous physical activities (2). More specifically, the need for surgery arises due to damage to the genicular artery that maintains vascularization of the ACL and its branches into terminal arteries. General reconstructive surgery cannot recreate the properties of the original ACL in patients, and any necessary grafts should be selected based on their recreative potential to mimic the original ligament. Key features of graft selection include looking into fixation, how quickly biological intervention takes place, recovery times, and the likelihood of donor site morbidity (3, 4). 

The two primary grafts considered for ACL reconstruction are classified as autographic or allographic. The allograph is advantageous due to lower incidence of donor site morbidity, greater overall graft strength, and often derived from a bone patellar tendon bone. Allograft use has increased due to avoidance of donor site morbidity, less postoperative pain, and quicker operation times. They pose a risk of increased immunogenicity, delayed graft incorporation, and higher risk of disease transmission (5)

Autographs, in contrast, are soft-tissue grafts that experience higher incidence of slippage and stability loss than their allograph counterparts and are commonly grafted from hamstring tendons (6). This can lead to slower healing and added stress at fixation sites within graft recipients following procedures yet is often favorable due to lower patient cost and greater donor availability (2).  In comparing both types of grafts, short-term outcomes are identical though those receiving allografts are able to return to normal day-to-day life sooner (6).

While there appears to be no major differences in graft failure between auto and allografts, bone patellar tendon bone allograft tissue presents a higher risk than that of autografts from the same tendon. This is believed to be due to both tissue type and graft preparation prior to surgical intervention (7). 

While both autografts and allografts offer individual benefits and downsides, both prove to be adequate and necessary for ACL reconstruction and allow patients the opportunity to return to a more active lifestyle. Understanding the functions and types of grafts allows individuals to be more informed on the processes surrounding ACL injury recuperation while knowing the treatments available to them. 

1. Maletis, G. B., Chen, J., Inacio, M., Love, R. M., & Funahashi, T. T. (2017). Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Allografts Compared With Autografts. The American journal of sports medicine, 45(6), 1333–1340. https://doi.org/10.1177/0363546517690386
2. Krupa, S., & Reichert, P. (2020). Factors influencing the choice of graft type in ACL reconstruction: Allograft vs autograft. Advances in clinical and experimental medicine : official organ Wroclaw Medical University, 29(10), 1145–1151. https://doi.org/10.17219/acem/124884
3. Cerulli, G., Placella, G., Sebastiani, E., Tei, M. M., Speziali, A., & Manfreda, F. (2013). ACL Reconstruction: Choosing the Graft. Joints, 1(1), 18–24. 
4. Macaulay, A. A., Perfetti, D. C., & Levine, W. N. (2012). Anterior cruciate ligament graft choices. Sports health, 4(1), 63–68. https://doi.org/10.1177/1941738111409890 
5. Asselmeier, M. A., Caspari, R. B., & Bottenfield, S. (1993). A review of allograft processing and sterilization techniques and their role in transmission of the human immunodeficiency virus. The American journal of sports medicine, 21(2), 170–175. https://doi.org/10.1177/036354659302100202
6. Biz, C., Cigolotti, A., Zonta, F., Belluzzi, E., & Ruggieri, P. (2019). ACL reconstruction using a bone patellar tendon bone (BPTB) allograft or a hamstring tendon autograft (GST): a single-center comparative study. Acta bio-medica : Atenei Parmensis, 90(12-S), 109–117. https://doi.org/10.23750/abm.v90i12-S.8973
7. Mariscalco, M. W., Magnussen, R. A., Mehta, D., Hewett, T. E., Flanigan, D. C., & Kaeding, C. C. (2014). Autograft versus nonirradiated allograft tissue for anterior cruciate ligament reconstruction: a systematic review. The American journal of sports medicine, 42(2), 492–499. https://doi.org/10.1177/0363546513497566