Inclusion Criteria:  From July 2005 to June 2008, 3757 ACLRs were performed in our department. A total of 111 patients chose to use allografts, and the other patients chose autologous semitendinosus and gracilis tendons (STGs). The patients selected DB or SB reconstruction based on their understanding about the information from the surgeons. Following the criteria of a prospective randomized study, 56 patients undergoing ACLRs with BPTB allografts were included in our study and were divided into a DB group and a SB group, each with 28 patients. 25 DB and 27 SB patients completed the final follow-up. Only patients between 16 and 50 years old who were undergoing primary operation were included, and younger patients had to have radiographic confirmation of a closed epiphysis.  Exclusion Criteria:  The exclusion criteria included age more than 50 years, narrow middle intercondylar width (<12 mm measured during operation with the knee flexed to 90°), revision reconstruction, multiligament injury, bilateral ACLRs, total meniscectomy or more than one-third partial meniscectomy, and severe cartilage injury.