Abstract Background: High tibial osteotomy (HTO) has traditionally been used to treat varus gonarthrosis in younger, active patients. Varus malignment increases the risk of progression of medial compartment osteoarthritis and an HTO can be performed to realign the mechanical axis of the lower limb towards the lateral compartment, thereby decreasing contact pressures in the medial compartment. Anterior cruciate liga-ment (ACL) insufficiency may lead to post-traumatic arthritis due to altered joint loading and associated injuries to the menisci and articular cartilage. Understanding the importance of posterior tibial slope and its role in sagittal knee stability has led to the development of biplane osteotomies designed to flatten the posterior tibial slope in the ACL deficient knee. Altering the alignment in both the sagittal and coronal planes helps improve stability as well as alter the load in the medial compartment. Aim of Study: Was to prospectively assess the effectiveness of management of varus angulated-ACL deficient knees by simultaneous arthroscopic ACL reconstruction and medial opening wedge high tibial osteotomy (HTO) using locked plate and synthetic bone graft (TUTOBONE®). The IKDC scoring system is used to assess the patients. Clinical outcomes are assessed preoperatively and at 20 months post-operatively. Patients and Methods: This prospective study was con-ducted in Cairo University Hospital, Orthopedic Surgery Department. The study included 20 patients aged 18-40 years oldwith primary ACL insufficiency combined with varus knee. They were admitted to the hospital mainly for instability complaint. All patients underwent arthroscopically assisted anatomic single bundle ACL reconstruction using hamstring tendon (HT) graft fixed with biodegradable screws simulta-neously with high tibial medial opening wedge osteotomy fixed with locked plate using iliac or synthetic bone grafts. All patients were followed prospectively for a minimum of 20 months. They were assessed clinically according to IKDC scoring system and radiologically by MRI and X-rays. Results: Radiological Evaluation revealed that there was a significant improvement in the varus degree after surgery when compared with before surgery. Postoperatively, 60% of the patients showed normal alignment, 10% valgus (mean: 1°  valgus) and 30% still varus (mean: 2.33°  varus, range: 1- 4°). All clinical scores improved significantly after surgery. The mean IKDC subjective score went from 42.9 points (range 34.2 to 57.7 points), preoperatively, to 79.2 points (range 72 to 95 points) at the end of follow-up. Also, the final IKDC ligament evaluation showed marked improvement in both subjective and objective criteria, with 80% of the patients rated themselves as normal and their knees did not affect their level of activity while 20% of the patients considered their knees nearly normal with slight effect on the level of activity. No patients considered their knees abnormal. Conclusion: It could be concluded that performing simul-taneous arthroscopic ACL reconstruction and medial opening wedge high tibial osteotomy (HTO) using locked plate and synthetic bone graft (TUTOBONE®)was effective for obtain-ing a satisfactory correction angle, good clinical outcomes and lower complication rate.