The management of an Anterior Cruciate Ligament (ACL) avulsion is principally by surgery. There are two major techniques in this regard; fixation through open surgery (arthrotomy) or arthroscopically-assisted repair. These are not new in the literature; however, the debate regarding the better approach is still under debate. This study focused on comparing outcome and consequences of arthroscopically-assisted vs. open surgery in repairing ACL avulsion. In a randomized clinical trial, 44 patients with unilateral ACL avulsion were recruited in Tabriz Shohada teaching Centre during a 12 month period of time. These patients were randomized in two equal age and sex-matched groups underwent either arthroscopically-assisted or open ACL repair. The constructive technique was the same in both groups without using any graft. The minimum follow-up period was 6 months including 3 weeks, 3 months and 6 months postoperatively. Range of Motion (ROM), laxity, Anterior Drawer Test (ADT) result, duration of hospital stay, wound status, nonunion and return to previous work were compared between the two groups. Mean time of suture removal (p = 0.10), minimum and maximum ROM at months 3 (p = 0.43 and 0.22, respectively) and 6 (p = 0.73 and 0.77, respectively), ADT at months 3 and 6 (p = 0.16 for both), laxity at month 6 (p = 0.28) and wound status at week 3 (p = 0.35) were not significantly different between the two groups. There was no case of nonunion at month 6 in either group. The mean hospital stay was significantly shorter in the arthroscopy group (3.77 +/- 0.92 vs. 2.50 +/- 0.51 days; p < 0.001). The mean laxity score was significantly higher in the open surgery group at month 3 (4.82 +/- 0.59 vs. 4.45 +/- 0.60; p = 0.05). The rate of nonunion was significantly higher in the open surgery group at month 3 (40.9% vs. 9.1%; p = 0.02). Patients in the arthroscopically-assisted technique group returned sooner to previous work (17.41 +/- 1.53 vs. 14.82 +/- 0.96 weeks; p < 0.001). Based on our results, arthroscopically-assisted reconstruction of ACL avulsion is superior to open surgery.