Background: Pes planovalgus is the most common foot deformity observed in cerebral palsy (CP) patients causing pain, gait abnormality, instability and in severe deformity. It can lead to brace intolerance. The treatment of this deformity should be directed to correct the foot malalignment, secure the stability of the foot during stance and correct the abnormal gait. After failure of conservative treatment, surgical treatment is the option. It varies from simple soft tissue procedures to tarsal osteotomies, subtalar extra-articular arthrodesis, intra-articular arthrodesis and triple arthrodesis. When these are compared, all techniques have advantages and disadvantages. Aim of the Work: This prospective clinical study is conducted to evaluate the short term outcome of the extra-articular subtalar arthrodesis using fibular graft that harvested from the junction between the proximal 1/3 and the distal 2/3 of the fibula in correction of flexible pes planovalgus in children with cerebral palsy. Patients and methods: We conducted a prospective study involving 13 patients (22 feet) with cerebral palsy who failed conservative treatment for more than 6 months. Postoperative complications were recorded. Assessment of the patients clinically and radiologically was done and compared to that of the preoperative data. Results: Clinical results were satisfactory in 21 feet and unsatisfactory in 1 foot according to kim et al scoring system. Radiologically; the anteroposterior talocalcaneal angle decreased from the median of 2°6 (range 1°1 – 5°6 ) preoperative to 9°.5 (range °1 – 3°5 ) post operative. The lateral talocalcaneal angle deceased from the mean of 42.0°5 ± 7.3°5 preoperative to 28.7°3 ± 8.5°1 postoperative. The anteroposterior talus-first metatarsal angle decrease from the median of 2°4 (range° 3 – 5°5 ) preoperative to° 8 (range° 1 – 3°9 ) postoperative. The lateraltalus-first metatarsal angle
decreased from the median of 2°0 (range °3 – 4°7 ) preoperative to 8°.5 (range °0 – 1°8 ) postoperative and the calcaneal pitch angle increased from the median of °5 (range -1°9 – 2°2 ) preoperative to 1°0 (range °2 – 1°7 ) postoperative. The postoperative changes were statistically highly significant. Conclusion: The extra-articular subtalar arthrodesis in our study as in others had been proved to be effective, safe, simple and non expensive procedure for correction of flexible pes planovalgus feet in children with cerebral palsy.