This research investigated the effectiveness of percutaneous Kirschner wire fixation in children with Jacob II and III lateral humeral condyle fractures. 28 children with Jacob II and III lateral humeral condyle fractures were treated with percutaneous Kirschner wire fixation under ultrasound localization, followed by cast immobilization for 4–5 weeks at our institution from January 2018 to April 2022. X-rays were evaluated on the first postoperative day to assess fracture reduction and Kirschner wire fixation. After 2 and 4 weeks, x-rays were taken to assess fracture healing and the presence of discomfort and infection was evaluated. After confirming fracture healing and callus formation, the cast and Kirschner wire were removed. Rehabilitation exercises were conducted following removal to restore elbow function. At the last follow-up, most results were excellent (n = 25) and good (n = 3) according to Flynn's criteria. Moreover, according to the Mayo Elbow Functional Score Scale (MEPS), all 28 children had excellent scores, with no significant difference in MEPS scores between the lesion and healthy sides (t = 1.533, p > 0.05). The present study substantiated that our novel approach is more convenient and effective, brings less trauma and complications and no radiation and deserves clinical promotion.