ACL TEARS: GRAFT CHOICES
One of the primary considerations in ACL reconstruction is selecting an appropriate graft based on each patient’s goals, activity demands, and personal preferences. The first decision one must make when selecting a graft is whether to use a tendon from a cadaver (allograft) or from themselves (autograft). The biggest difference between the two graft options is the rate of re-tear (failure) of the reconstructed ligament after surgery. Allograft ACLs have been associated with 13-fold higher re-tear rate when compared to autograft ACLs, especially in younger patients.1 In addition to a lower re-tear rate, autograft has been shown to have higher return to sports and patient-reported outcomes at 2 and 6 years after surgery.2.
Nevertheless, there are a few scenarios where an allograft may be considered, such as in less active individuals over the age of 35 and in certain revision ACL surgeries. The potential advantages of an allograft ACL include less immediate post-operative pain, faster return to work, no donor site pain (pain from where the graft was taken), and smaller/fewer incisions. When an allograft is selected in the appropriate patient, newer graft preparation techniques have been shown to decrease the risk of re-rupture seen in previous studies.3-7 One additional concern specific to the use of allograft tissue is the theoretical risk of disease transmission. To date, there has been only one case of HIV transmission in 1985 and 2 cases of hepatitis C transmission in 1991. However, with today’s screening and sterilization methods, the risk of viral infection with HIV is between 1 out of 1.6 million and 1 out of 8,000,000.8
For the vast majority of patients, an autograft ACL is recommended. There are several autograft options, each with their own risks and benefits. The first option is to use a portion of one’s patellar tendon along with a piece of bone from the knee cap and a piece of bone from the patellar tendon insertion site on the tibia (bone-patellar tendon-bone, or BTB graft). The second option is to create an ACL autograft from one’s own hamstring tendons. The final autograft option utilizes a portion of one’s own quadriceps tendon.
When compared to the BTB graft, the hamstring graft results in a smaller scar and less post-operative pain, leading to easier recovery in the first few months following surgery. However, hamstring grafts are more unpredictable in size and can result in chronic hamstring-related pain and weakened knee flexion.9 Also, the hamstring muscles are co-stabilizers for the ACL and some believe it is detrimental to weaken them in the setting of an ACL injury.
A level II cohort study of 45,998 patients revealed small, but significant differences in failure rates after 5 years between hamstring tendon autografts (4.2%) and bone-patellar tendon-bone autografts (2.8%).10 It is for these reasons that many professional athletes have historically chosen the bone-patellar tendon-bone autograft. However, the disadvantages of the patellar tendon option have raised concern among both patients and surgeons. The use of a BTB
autograft results in a larger, less cosmetic scar and is more painful than other options, making the first few months of rehab more difficult. Long-term, a BTB graft can also result in significant anterior knee pain. This symptom may be present with regular activities, in up to 17.4% of patients,11 or when kneeling, in up to 54% of patients.12 Furthermore, injury to a nerve that provides sensation to the front of the knee has been reported in up to 73% of cases13 after a BTB graft harvest and up to 86% of cases following hamstring tendon harvest.14
In more recent years, use of a quadriceps tendon autograft for ACL reconstruction has gained considerable popularity due to the drawbacks of other graft options. A quadriceps graft can be harvested through a much smaller and more cosmetic incision, resulting in a graft with a significantly lower risk of nerve injury/sensory loss15 and anterior knee pain16 compared to hamstring and BTB grafts. Despite the smaller incision, the mass of the quadriceps graft is approximately 50% greater than a BTB graft of similar width,17. resulting in comparable graft survival rates and functional outcomes compared with both BTB and hamstring grafts.16,18
In summary, ACL reconstruction surgery consists of replacing your torn ligament with new tissue. Allograft or autograft tissue can be used. In people under the age of 35, allograft has a higher failure rate and is generally avoided except in special situations. Autograft is generally associated with lower re-rupture rates and better knee function. Hamstring tendons and BTB grafts have long track records, but have considerable drawbacks. Quadricep tendon autografts yield equivalent functional outcomes and graft survival rates, but with fewer complications and better cosmesis.
1. Kaeding CC, Pedroza AD, Reinke EK, Huston LJ, Hewett TE, Flanigan DC, Spindler K, MOON Knee Group (2017) Change in anterior cruciate ligament graft choice and outcomes over time. Arthroscopy 33:2007–2014.
2. Spindler KP, Huston LJ, Wright RW, et al. The prognosis and predictors of sports function and activity at minimum 6 years after anterior cruciate ligament reconstruction: a population cohort study. Am J Sports Med. 2011 Feb;39(2):348-59.
3. Lamblin CJ, Waterman BR, Lubowitz JH. Anterior cruciate ligament reconstruction with autografts compared with non-irradiated, non-chemically treated allografts. Arthroscopy. 2013 Jun;29(6):1113-22.
4. Wei J, Yang HB, Qin JB1, Yang TB. A meta-analysis of anterior cruciate ligament reconstruction with autograft compared with nonirradiated allograft. Knee. 2015 Oct;22(5):372-9.
5. Zeng C, Gao SG, Li H, Yang T, Luo W, Li YS, Lei GH. Autograft Versus Allograft in Anterior Cruciate Ligament Reconstruction: A Meta-analysis of Randomized Controlled Trials and Systematic Review of Overlapping Systematic Reviews. Arthroscopy. 2016 Jan;32(1):153-63.e18.
6. Mariscalco MW, Magnussen RA, Mehta D, Hewett TE, Flanigan DC, Kaeding CC. Autograft versus nonirradiated allograft tissue for anterior cruciate ligament reconstruction: a systematic review. Am J Sports Med. 2014 Feb;42(2):492-9.
7. Maletis GB, Chen J, Inacio MCS, Love RM, Funahashi TT. Increased risk of revision after anterior cruciate ligament reconstruction with soft tissue allografts compared with autografts: graft processing and time make a difference. Am J Sports Med. 2017 Jul;45(8):1837–44.
8. Baer GS1, Harner CD. Clinical outcomes of allograft versus autograft in anterior cruciate ligament reconstruction. Clin Sports Med. 2007 Oct;26(4):661-81.
9. Samuelsson K, Andersson D, Karlsson J (2009) Treatment of anterior cruciate ligament injuries with special reference to graft type and surgical technique: an assessment of randomized controlled trials. Arthroscopy 25:1139–1174
10. 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.
11. Freedman KB1, D’Amato MJ, Nedeff DD, Kaz A, Bach BR Jr. Arthroscopic anterior cruciate ligament reconstruction: a metaanalysis comparing patellar tendon and hamstring tendon autografts. Am J Sports Med. 2003 Jan-Feb;31(1):2-11.
12. Roe J1, Pinczewski LA, Russell VJ, Salmon LJ, Kawamata T, Chew M. A 7-year follow-up of patellar tendon and hamstring tendon grafts for arthroscopic anterior cruciate ligament reconstruction: differences and similarities. Am J Sports Med. 2005 Sep;33(9):1337-45.
13. Lund B, Nielsen T, Fauno P (2014) Is quadriceps tendon a better graft choice than patellar tendon? A prospective randomized study. Arthroscopy 30(5):593–598.
14. Hamid M, Mohammad M, Hossein A (2018) Injury to the infrapatellar branch of the saphenous nerve during ACL reconstruction with hamstring tendon autograft: a comparison between oblique and vertical incisions. Arch Bone Jt Surg 6(1):52–56.
15. Mouarbes D, Dagneaux L, Olivier M, Lavoue V, Peque E, Berard E, Cavaignac E. Lower donor‑site morbidity using QT autografts for ACL reconstruction. Knee Surg Sports Traumatol Arthrosc. 2020 Feb 4. doi: 10.1007/s00167-020-05873-1.
16. 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.
17. Fulkerson JP, Langeland R (1995) An alternative cruciate reconstruction graft: the central quadriceps tendon. Arthroscopy 11:252–254.
18. Slone HS, Romine SE, Premkumar A, Xerogeanes JW (2015). Quadriceps tendon autograft for anterior cruciate ligament reconstruction: a comprehensive review of current literature and systematic review of clinical results. Arthroscopy 31:541–554..
If you are experiencing any ACL issues or would like to learn more don’t hesitate to reach out.
Nels Sampatacos, MD
Orthopedic Surgeon and Sports Medicine Specialist
