Post-operative complications following primary ACL reconstruction using allogenic and autogenic soft tissue grafts: Increased relative morbidity risk is associated with increased graft diameter

Abstract Background The purpose of this study is to compare the risk of peri-operative complication events associated with allogenic and autogenic grafts during routine follow-up for six months after primary arthroscopic anterior cruciate ligament (ACL) reconstruction surgery. Methods A retrospective cohort study identified patients that underwent ACL reconstruction via an arthroscopically assisted single tunnel technique. Fixation was primarily cortical suspension (endobutton) from the femora and bicortical fixation (Washer-loc) in the tibia. Patients were monitored for six months following surgery. Morbidity was defined as complications during this period requiring medical or surgical intervention. Risk of complications was compared according to tissue type and patient characteristics. The Cochran–Mantel–Haenszel method was applied to estimate risk ratios (RR) and confidence intervals (CI) as the measure of association between graft type and morbidity risk. Results The cohort included 413 eligible patients. Sixty six percent received allograft tissue, while the remainder received autograft tissue. Morbidity risk was 7.0% among patients receiving allograft tissue and 2.8% among patients receiving autograft tissue. Allograft demonstrated elevated risk of complication versus autograft (RR = 2.3 (95% CI: 0.9–7.2)), though the data are of borderline significance (p = 0.11). Complications were associated with larger graft diameter in comparison to patients who experienced no complication (9.0 +/− 1.2 mm v. 8.4 +/− 1.0 mm, p = 0.005). Conclusion The relative morbidity risk was about two-fold greater among patients receiving allograft tissue. Regardless of tissue type, graft size was larger among patients who experienced a complication. Level of evidence Level III.