ObjectiveTo investigate the surgical method and preliminary effectiveness of Ilizarov technique in the treatment of lower limb deformity caused by achondroplasia. MethodsThe clinical data of 38 patients with lower limb deformity caused by achondroplasia treated by Ilizarov technique between February 2014 and September 2021 were retrospectively analyzed. There were 18 males and 20 females, the age ranged from 7 to 34 years, with an average of 14.8 years. All patients presented with bilateral knee varus deformity. The preoperative varus angles was (15.2±4.2)°, and knee society score (KSS) was 61.8±7.2. Nine of these patients underwent tibia and fibula osteotomy, 29 cases underwent tibia and fibula osteotomy and bone lengthening at the same time. Full-length bearing position X-ray films of bilateral lower limbs were taken to measure the bilateral varus angles, analyze the healing index, and record the occurrence of complications. KSS score was used to evaluate the improvement of knee joint function before and after operation. Results All 38 cases were followed up 9-65 months, with an average of 26.3 months. Needle tract infection occurred in 4 cases and needle tract loosening occurred in 2 cases after operation, which were improved after symptomatic treatment such as dressing change, Kirschner wire change, and oral antibiotics, and no neurovascular injury occurred in all patients. The external fixator was worn for 3-11 months after operation, with an average of 7.6 months, and the healing index was 43-59 d/cm, with an average of 50.3 d/cm. At last follow-up, the leg was 3-10 cm longer, with an average of 5.5 cm. The varus angles was (1.5±0.2)° and the KSS score was 93.7±2.6, which significantly improved when compared with those before operation (P<0.05). ConclusionIlizarov technique is a safe and effective method for the treatment of short limb with genu varus deformity caused by achondroplasia, which can improve the quality of life of patients.