Clinical Outcome and Failure Risk Comparison between the Use of Autograft and Allograft Tissue in ACL Reconstruction Surgeries

______________________________________ Page 3 Introduction_____________________________________ Page 4 Procedure_______________________________________ Page 7 Results_________________________________________ Page 10 Discussion______________________________________ Page 13 References______________________________________ Page 16 Abstract Background: The use of both autograft as well as allograft tissue in anterior cruciate ligament reconstruction surgeries, performed by present day surgeons in patients of a wide age range, is prevalent. However, failure risks in such surgeries depend on a multitude of factors. In order to appropriately use the more suitable type of tissue in patients of ACL reconstruction surgeries, some of the main factors affecting failure risks are investigated. Procedures: Extensive data regarding ACL reconstruction surgery patients was collected through MOON (Multi-Center Orthopedic Outcomes Network) patient questionnaires and surgeon forms. The data processing was completed in three parts. In the first part, the occurrence of re-tear in ACL reconstruction patients with allografts vs. those with autografts was determined as a binary outcome (tear/no tear). In addition, a logistic regression was done on any patient-associated factors that are related to incidence of re-tear. The second part of the study was focused on the evaluation of a dependent variable defined as “time to re-tear” in allograft ACL reconstructions, and investigating, using a Cox regression, its link to factors such as gender, age, and graft preparation criteria. Finally, the last part of the study is part of a survival analysis comparison between the time to re-tear of allografts and autografts (failure rates) in terms of the implications of factors such as the Marx score, gender and age. Outcome: Firstly, allograft reconstructions were 3.242 times more likely to re-tear than autografts and the factors of age and graft type (auto/allo) significantly contributed to incidence of re-tear. Secondly, graft preparation factors showed no significant effect on the time to re-tear of allograft ACL reconstructions. Finally, in the third part of the study, the relative risk of re-tear in allograft reconstructions is 2.283 times higher than autograft ones with age affecting relative re-tear risk, while failure rates (times to re-tear) were similar between the two grafts. Conclusion: Generally, allografts have a higher risk of re-tear than autografts. In addition to that, age is a significant factor in affecting risk of re-tear.Background: The use of both autograft as well as allograft tissue in anterior cruciate ligament reconstruction surgeries, performed by present day surgeons in patients of a wide age range, is prevalent. However, failure risks in such surgeries depend on a multitude of factors. In order to appropriately use the more suitable type of tissue in patients of ACL reconstruction surgeries, some of the main factors affecting failure risks are investigated. Procedures: Extensive data regarding ACL reconstruction surgery patients was collected through MOON (Multi-Center Orthopedic Outcomes Network) patient questionnaires and surgeon forms. The data processing was completed in three parts. In the first part, the occurrence of re-tear in ACL reconstruction patients with allografts vs. those with autografts was determined as a binary outcome (tear/no tear). In addition, a logistic regression was done on any patient-associated factors that are related to incidence of re-tear. The second part of the study was focused on the evaluation of a dependent variable defined as “time to re-tear” in allograft ACL reconstructions, and investigating, using a Cox regression, its link to factors such as gender, age, and graft preparation criteria. Finally, the last part of the study is part of a survival analysis comparison between the time to re-tear of allografts and autografts (failure rates) in terms of the implications of factors such as the Marx score, gender and age. Outcome: Firstly, allograft reconstructions were 3.242 times more likely to re-tear than autografts and the factors of age and graft type (auto/allo) significantly contributed to incidence of re-tear. Secondly, graft preparation factors showed no significant effect on the time to re-tear of allograft ACL reconstructions. Finally, in the third part of the study, the relative risk of re-tear in allograft reconstructions is 2.283 times higher than autograft ones with age affecting relative re-tear risk, while failure rates (times to re-tear) were similar between the two grafts. Conclusion: Generally, allografts have a higher risk of re-tear than autografts. In addition to that, age is a significant factor in affecting risk of re-tear.