Abstract Purpose The aim of this work is to study the result of posterior subtalar fusion as a modality of treatment of idiopathic spasmodic valgus feet. We study the effect of using a tightly impacted iliac crest bone graft to achieve stable joint distraction without additional fixation. Materials and Methods The study was done in the period between June 2017 and January 2019. Patients’ age ranged from 12 to 16 years. Patients were all treated with subtalar fusion at the level of the posterior facet. A wedged tricortical iliac crest bone graft was tightly impacted in the joint with its base facing laterally. No additional fixation methods were used. Patients were followed radiologically and functionally using the American Orthopedic Foot and Ankle Society Ankle–Hind foot scale (AOFAS-AHS). Results The study included 12 males and one female with a mean age of 13.5 ± 1.2 years. Five cases were bilateral and eight cases had unilateral affection with a total 18 feet. The mean follow-up period averaged 12 months (6–18) months. The AOFAS-AHS significantly increased from a preoperative mean of 41.2 ± 1.8 points to a postoperative mean of 82.8 ± 3.6 points (P value <0.001), with a significant improvement in the radiological parameters used to evaluate the deformity. Conclusion Operative treatment in form of subtalar fusion is a good surgical option that showed significant improvement of symptoms and deformity correction. The technique of distraction bone block using wedged iliac graft allows a stable fusion and avoids hardware complications.