70 patients with an acute anterior cruciate ligament (ACL) injury were randomized to undergo reconstruction within 8 days of the injury (sub-acute group) or after range of motion (ROM) normalization (delayed group). The purpose of the study was to assess whether the timing of the reconstruction had an impact on postoperative rehabilitation, and whether post-surgery stiffness was a concern with modern arthroscopic approaches, as had been associated in the past. Range of motion and functional outcome were assessed at 3-month and 6-month follow-up. Results demonstrated no significant differences in range of motion between groups at 3 months. At 6 months, one leg hop difference compared to contralateral limb favoured sub-acute reconstruction compared to delayed reconstruction, while all other functional outcomes were similar between groups.