Objective: Anterior cruciate ligament (ACL) tears are common injuries in adolescent athletes, especially in those who bear high stress on their knees due to shearing forces. The goal of the surgical procedures in skeletally immature patients is to restore joint stability avoiding the adverse effects on the growth process. The aim of this study was to verify the return of the skeletally immature professional athletes to sports in the long-term, following ACL reconstruction with the original all-inside technique and with manual drilling. Methods: This study included 24 athletes (14 boys, 10 girls; mean age: 13.15 years, range: 9e14 years) who had radiographic evidence of open physes, were less than 14 years of age at the time of surgery and those with a minimum follow-up of eight years. All patients completed a questionnaire, the IKDC subjective knee evaluation form, and Tegner Activity Scale. Biomechanical outcomes of the KT-1000 arthrometer, gait analysis, and stabilometric and isokinetic results were also evaluated. A plain radiograph of both lower limbs was taken to obtain a precise measurement of the limb length and mechanical axis angles. Results: The patients returned to sport activities in a mean time of 6.43 months. No rerupture or resurgery due to growth abnormalities was observed. The mean difference in length between the operated and contralateral legs was 0.4 (range: 0.2 to 0.7) cm. The mean side-to-side difference measured with the KT-1000 arthrometer was 5.2 (range: 3.5 to 7) mm in the preoperative and 0.8 (range: 0 to 2.5) mm in the postoperative measurements. Conclusion: In conclusion, the original all-inside technique with manual drilling with a half tunnel and short graft seems to be a very effective technique for the surgical management of ACL injuries in pediatric/ adolescent athletes. A good rate of return to sports at pre-injury levels or higher, high patient satisfaction and a decent motor and proprioceptive function is possible as shown by our analysis. Level of evidence: Level IV, Therapeutic study.