For proximal varus osteotomy of the femur in children, a stable fixation, is a concern regarding the safety and the protection of the surgery. The methods of fixation are mostly represented by plating systems; however, the tension band wiring is a simple and eligible option for fixation of proximal femur osteotomy. The purpose of this retrospective case series study is to evaluate outcomes and bone remodelation after using the tension band wiring technique to fixate proximal femoral varus osteotomies in children.The study enrolled 20 patients who underwent femoral varus osteotomy to treat Legg-Calvé-Perthes disease and other causes of necrosis of the femoral head. The mean patient age at the time of surgery was 7.4 ± 2.3 years (range, 4.3-13.8 y), and the follow-up period averaged 10 ± 4.3 years (range, 4.7-20.8 y). To assess the effects of the osteotomy at the neck-shaft angle and its evolution over time, radiographs obtained preoperatively and during the follow-up were analyzed. The neck-shaft angle was measured independently by 2 observers, and intraclass correlation coefficients (ICCs) were assessed for reliability.The ICC analysis showed good reliability. There was a significant reduction in the neck-shaft angle (P < 0.001) between the preoperative and the immediate postoperative periods, with an estimated difference of 14.3°. Between the immediate and the early postoperative periods, the estimated difference was 2.1°, which indicated a significant increase in the neck-shaft angle (P = 0.003). Between the early postoperative period and the final evaluation, there was a significant increase (P < 0.001), with an estimated difference of 7.0°. No implant failures or other complications were observed, but 1 case of peri-implant femoral fracture occurred >17 years postsurgery.The tension band wiring technique proved to be a simple and effective method for fixating proximal femoral varus osteotomy in children.The level IV is appropriated for our study (case series, retrospective).