PurposeThe purpose of this study was to compare the outcomes of hamstring tendon (HT) and quadriceps tendon (QT) autografts for anterior cruciate ligament (ACL) reconstruction in patients older than 50 years in terms of patient-reported functional outcomes, graft failure rates, complications, return to sports activity and the preference for sports. MethodsBetween 2010 and 2022, prospectively collected data were obtained from an institutional database. Patients older than 50 years with primary arthroscopic ACL reconstruction using either HT or QT autograft and a minimum of 2 years of follow-up were included. Patients with concomitant meniscus, cartilage and MCL injury were also included. Patients undergoing a revision ACL reconstruction or undergoing a primary ACL reconstruction using a graft other than HT or QT autograft, and patients with a contralateral knee injury or ipsilateral osteoarthritis (Ahlback stage 2 or higher) were excluded. Patients were evaluated for pre-injury and 2-year follow-up Lysholm knee score, Tegner activity level, Visual Analog Scale (VAS) for pain, graft failure, quadriceps tendon rupture, and return to sport. Mann-Whitney test was used for unpaired samples, whereas the Friedman test was used for analyzing variables over time. The chi-square statistic test was used to determine differences in categorical data between groups ResultsThe number of patients in the QT and HT groups was 85 and 143 respectively. The mean age was 54.4 [50-65] and 56.4 [50-65] for the QT and HT groups respectively, 49% and 51% were males in the QT and HT groups respectively. The two groups did not differ significantly in terms of age, gender, time from injury to surgery and concomitant injuries. No significant differences were found in the pre-injury patient-reported outcome scores (PROMs) as Lysholm, Tegner activity level and VAS for pain between the two groups (p>0.05). At the 2-year follow-up, Lysholm knee score, Tegner activity level and VAS for pain improved to pre-injury level and no significant difference was noted between pre-injury and 2-year follow-up functional scores between the two groups (p>0.05).Furthermore, at the 2-year follow-up, Lysholm score, and VAS didn't show significant differences between QT and HT groups. (p=.390; p= .131). Similarly, no differences have been reported in Tegner activity level scores between HT and QT groups at 2 years of follow-up. No significant differences in terms of minimal clinically important difference (MCID) have been detected between the two groups for Lysholm and Tegner activity scores (p = 0.410 and p = 0.420 for Lysholm score and Tegner activity level score respectively).The two groups did not differ in terms of patient’s percentage of sports participation at baseline, and 2 years of follow-up (p>0.05). A significant decrease (p=0.01) in skiing/snowboarding was reported in the HT group at a 2-year follow-up compared to baseline [116 (81%) vs 98 (69%)]. No case of graft failures and quadriceps tendon rupture was reported in either of the groups. ConclusionArthroscopic ACL reconstruction by using HT or QT autograft in athletically active older than 50 years patients provide satisfactory patient-reported functional outcomes and allows recovery of the pre-injury level of activity.