Objective  To investigate the therapeutic effect of the fibular head composite flaps for reconstruction of bone and skin defect at medial malleolus in children.  Methods  A retrospective case series study was conducted to analyze 5 children (3 males and 2 females, aged 3-12 years) with internal malleolus and skin soft tissue defects admitted to the Yidu Central Hospital of Weifang between March 2010 and June 2018. The medial malleolus was defected (3 children at the right foot and 2 at the left foot) combined with skin defect around the medial malleolus. Dimension of skin defect was 3.0 cm×3.5 cm to 6.0 cm×10.5 cm, and of bone defect was 1.0 cm×1.0 cm to 2.0 cm×3.0 cm. The complex of the vascularized fibular head epiphysis was adopted to repair the defects at one stage. The donor sites were repaired with direct suture in 4 children and with skin graft in 1. Appearance, texture, elasticity and color of the flaps, length of lower limbs, ankle joint deformity, ankle joint range of motion, function of knee and ankle joint evaluated by using American Orthopedic Foot and Ankle Society (AOFAS) score and image change were observed. The flap donor area was evaluated for deformity, pain and sensory abnormality in the common peroneal nerve innervation area, and range of motion.   Results  All the composite tissue flap survived with good blood circulation, and the wound healed by first intention. All children were followed up for 6-30 months (mean, 21 months). The appearance of the flap was good, and the texture, elasticity and color were similar to the surrounding area, without cicatricial contracture. The legs were the same length, and there was no deformity of the ankle joint. None had ankle joint deformity, with satisfactory loading and walking function. Comparison of ankle movement before and after operation showed significant differences: dorsal extension angle［（4.4±1.1)° vs. (13.2±2.4）°］, plantar flexion angle［（12.4±1.8)° vs.(34.8±4.8）°］ （both P＜0.05）. Three children were graded as excellent and two good according to AOFAS score. X-ray showed that the gap between ankle acupoints and longitudinal development of the medial malleolus were almost synchronized with the healthy limbs. No signs of joint wear or early closure of epiphysis of medial malleolus was observed, and ossification center was obvious or showed gradually increase. The donor knee joint had normal flexion and extension function, without deformity, pain, or abnormal sensation in the common peroneal nerve innervation area.  Conclusions  The complex of vascularized fibular head epiphysis and tissue flap can repair the bone and adjacent soft tissue defect of the medial malleolus in children at one stage, with good appearance recovery and ankle joint function recovery. The reconstructed medial malleolus can develop with the growth of children and has no effect on the function and feel of the knee joint in the donor area. It is a satisfactory method of reconstructing the traumatic defect of medial malleolus in children.