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Anterior cruciate ligament reconstruction- allograft versus autograft

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Anterior Cruciate Ligament Reconstruction - Allograft versus Autograft

Anterior Cruciate Ligament Reconstruction - Allograft versus AutograftAndris Levis MF VIversusKristaps Blms MF VI

Mentor: Dr. Modris Ciems

#Anterior Cruciate Ligament (ACL)Functions:Limits the forward motion of the tibia 1; Prevents hyperextension of the knee 1;Provides roughly 90% of stability in the knee joint 1

#one of 4 major ligaments of the knee joint. ACL is one of two cruciate ligaments inside the knee that cross the other ligament to form an X. An ACL is attached to the the tibia(shin bone) and crosses over the front attaching to the femur(thigh bone). ligament is 31 to 35mm in length and 31.3mm2in cross section2

Incidence of InjuryAnnual incidence of more than 200,000 cases with ~100,000 of these knees reconstructed 2;Most prevalent (1 in 1,750 persons) in patients 15-45 years of age 1;An estimated 70% of ACL injuries are sustained through non-contact mechanisms, while the remaining 30% result from direct contact. 1

#ACL injury has an annual incidence of more than 200,000 cases with ~100,000 of these knees reconstructed annually3. The majority of ACL injuries (~70%4) occur while playing agility sports, and the most often reported sports are basketball, soccer, skiing, and football. An estimated 70% of ACL injuries are sustained through non-contact mechanisms, while the remaining 30% result from direct contact.3,4ACL injury is most prevalent (1 in 1,750 persons) in patients 15-45 years of age.4 It is more common in this age group in part because of their more active lifestyle as well as higher participation in sports.

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Indications for surgeryKnee instability 5;Combined injuries (30-50%) 3;ACL reconstruction could prevent further damage 4;High-demand patients 5

#Unhappy triad- acl, mcl,mm4

#Single bundle bone tendon bone5

#Patient related factorsAllograftNo donor site morbidity 6; No weakening of the flexor/extensor apparatuses 8;Faster return to activities of daily living 8;Least painful post-operatively 8;Higher IKDC scores 10;Patients older than 45 years 8;Lower demand patients 8;Multiligamentous knee injury reconstructions 8;Revision ACL surgery. 8

AutograftYoung patients 11Athletes 12No difference in Lysholm II and KT 1000 scores 13More pain immidiate rehabilitation and activities possible - paradox

#The ideal ligament replacement should be readily available; it should be of sufficient length and diameter; it should have biomechanical properties similar to the ligament it replaces; it should not disturb normal structures; and it should retain or develop a vascular supply. Although autogenous tissues currently are the most commonly used grafts for reconstruction of the cruciate ligament, these transfers sacrifice a normal musculotendinous structure in an already deficient knee, adding to the functional disturbance. Extensive surgical exposure, long tourniquet times, and prolonged rehabilitation are other disadvantages of these techniques.7

Surgery related factorsAllograftSmaller incision 8;Reduced operative time 6;Smaller risk of complications under anesthesia 5;No risk of patellar fracture 9;No need for an assistant.

AutograftOperative time can be evened with asisstantLower cost $4,587 92 min vs $3,849 125 min 14

#Transplant related factorsAllograftGreater availability 8;Larger cross sectional size 8;Potential graft tissue source for backup 9;AutograftGreater avalailabilty in Latvia Lower tear rate 8,9% vs 3,5% 11More than 10% difference in patients less than 18yo 11At 6 months better AP restraint to AP force, more cross sectional area, twice load to failure strentgh 15Loses less time zero strenght 17

#Autografts and allografts both go through four stages after transplantation: necrosis, revascularization, cellular proliferation, and remodeling. After incorporation, however, neither autograft nor allograft tendons have been demonstrated to return to their original strength. Most reports show 30% to 40% ultimate load strengths. Because of this consistent reduction in strength, most surgeons prefer to use grafts or combinations of grafts that begin with more than 100% of anterior cruciate ligament strength, which should result in sufficient strength after incorporation.9

Biological factorsAllograft

Low dose irradiation - eliminate bacteria 7;High dose irradiation - eliminate both bacterial and viral pathogens 7;The estimated risk of HIV transmission is 1:8,000,000. 7

AutograftHistocompatibilityNo infection transmission riskFaster incorporation 17

#Allografts can be irradiated or non-irradiated; however, there is concern of compromised graft integrity and decreased time-zero biomechanical strength with irradiated grafts.53 Low dose irradiation < 20 kGy has been shown to affectively eliminate bacteria, but only irradiation greater than 30 kGy has been shown to eliminate both bacterial and viral pathogens.43 Irradiation greater than 20 kGy in a single dose causes substantial changes in the structural properties of the graft,14 which likely causes its inferior clinical outcomes. The risk can be minimized by using a reputable tissue bank and the surgeon must be fully aware of the protocol used by the tissue bank to assure it meets the standards outlined by the AAOS. Most grafts 8 currently undergo low dose irradiation that allows for the destruction of bacteria and rely on donor screening and nucleic acid testing to reduce the risk of viral contamination as irradiation at the level needed for viral elimination would significantly compromise graft biomechanical properties.With current serologic tests to screen donors and tissue processing and storage, the estimated risk of HIV transmission with connective tissue allografts is 1:8,000,000.10

Bottom line The surgeon has many choices when it comes to graft selection for ACL reconstruction; There are certain situations in which one graft may be favored over another;No graft is perfect;Individual approach is the most important

#such as in the young, athletic population where autograft tissue should be used.

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Future?

#LiteratureGriffin LY. Noncontact Anterior Cruciate Ligament Injuries: Risk Factors and Prevention Strategies. Journal of the American Academy of Orthopaedic Surgeons. 2000;8:141-150Miyasaka KC, Daniel DM, Stone ML. The incidence of knee ligament injuries in the general population. Am J Knee Surg 1991;4:43-48.Hefzy MS, Grood ES. Ligament restraints in anterior cruciate ligament-deficient knees. In: Jackson DW, Arnoczky SP, Woo SL-Y, Frank CB, Simon TM, eds. The Anterior Cruciate Ligament. Current and Future Concepts. New York: Raven Press, 1993;141-151.Cannon W, Jr, Vittori J. The incidence of healing in arthroscopic meniscal repairs in anterior cruciate ligament-reconstructed knees versus stable knees. Am J Sports Med 1992;20(2):176-181.Johnson RJ, Beynnon BD, Nichols CE, et al. Current concepts review. The treatment of injuries of the anterior cruciate ligament. J Bone Joint Surg Am 1992;74A:140-151.Fu FH, Jackson DW, Jamison J, et al. Allograft reconstruction of the anterior cruciate ligament. In: Jackson DW, Arnoczky SP, Woo SL-Y, Frank CB, Simon TM, eds. The Anterior Cruciate Ligament. Current and Future Concepts. New York: Raven Press, 1993;325-338.Pruss A, Kao M, Gohs U, Koscielny J, von Versen R, Pauli G. Effect of gamma irradiation on human cortical bone transplants contaminated with enveloped and non-enveloped viruses. Biologicals 2002;30:125-133.Shelton WR, Papendick L, Dukes AD. Autograft versus allograft anterior cruciate ligament reconstruction. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association. Aug 1997;13(4):446-449.Miller SL, Gladstone JN. Graft selection in anterior cruciate ligament reconstruction. The Orthopedic clinics of North America. Oct 2002;33(4):675-683.Robert H. Miller and Frederick M. Azar. Campbell's Operative Orthopaedics, Chapter 45, 2121-2297.e16

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Kaeding CC, Aros BC, Pedroza A, et al. Allograft Versus Autograft Anterior Cruciate Ligament Reconstruction: Predictors of Failure from a MOON Prospective Longitudinal Cohort. Sports Health 2011;3:73-81Pallis M, Svoboda SJ, Cameron KL, Owens BD. Survival Comparison of Allograft and Autograft Anterior Cruciate Ligament Reconstruction at the United States Military Academy. Am J Sports Med 2012;40:12426. doi:10.1177/0363546512443945.Chang SKY, Egami DK, Shaieb MD, Kan DM, Richardson AB. Anterior cruciate ligament reconstruction: allograft versus autograft. Arthroscopy 2003;19:45362. doi:10.1053/jars.2003.50103.Greis PE, Koch BS, Adams B. Tibialis anterior or posterior allograft anterior cruciate ligament reconstruction versus hamstring autograft reconstruction: an economic analysis in a hospital-based outpatient setting. Arthroscopy 2012;28:1695701. doi:10.1016/j.arthro.2012.04.144.Gulotta LV, Rodeo SA. Biology of autograft and allograft healing in anterior cruciate ligament reconstruction. Clin Sports Med 2007;26:509-524.Jackson DW, Grood ES, Goldstein JD, et al. A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat model. Am J Sports Med 1993;21:176-185. Jackson DW, Corsetti J, Simon TM. Biologic incorporation of allograft anterior cruciate ligament replacements. Clin Orthop Relat Res 1996:126-133.

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