Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Flexible pes planovalgus is a common deformity in young adolescents. It can interfere with daily activities and athletic participation. If conservative treatment fails, operative intervention is justified. Operative interventions include lateral column lengthening alone, multiple osteotomies (medial translation calcaneal osteotomy, lateral column lengthening, and Cotton osteotomies), and arthroereisis. All these options can be combined with gastrocnemius recession, excision of accessory navicular, or other soft tissue procedures. Arthroereisis is a highly controversial procedure with a great debate regarding indications, safety and clinical outcome. The literature comparing corrective osteotomies to arthroereisis in young adolescents is deficient and non conclusive. This study was done to compare the clinical and radiological outcome of multiple corrective osteotomies to arthroereisis in young adolescents. Methods: This is a case control prospective study that included 40 feet (20 feet in each group) in 25 patients with flexible pes planovalgus deformity in patients aged 10 to 13 years, after failure of conservative treatment. Exclusion criteria included generalised ligamentous laxity, neurogenic disorders, and rigid deformity. Cases with severe talonavicular uncoverage (angle more than 40 degrees) were excluded as this might be a contraindication to arthroereisis. Group 1 underwent correction by multiple osteotomies (medial translation calcaneal osteotomy, lateral column lengthening, and Cotton osteotomies) and group 2 underwent arthroereisis using a conical titanium subtalar spacer. Gastrocnemius recession and resection of painful accessory navicular were done if indicated in both groups. Clinical outcome was assessed using AOFAS, FAAM scores and subjective patient satisfaction. Radiological assessment included lateral talocalcaneal angle, anteroposterior and lateral talus first metatarsal angle, talonavicular coverage angle, and calcaneal pitch angle. Results: The mean follow up in group 1 was 29 months compared to 25 months in group 2. Preoperatively, there was no statistically significant difference between the two groups regarding patient demographics, clinical scores, or radiological measurements. Clinically, 18 patients were satisfied in group 1, compared to 17 patients in group 2. The mean AOFAS score improved significantly from 73 (62-90) to 91(73-100) in group 1 and from 73 (62-90) to 89 (73-100) in group 2. FAAM score improved significantly from 76% (68-87) to 95.75% (74-100) in group 1, and from 73% (62-86) to 91% (71-98) in group 2. The difference between the two groups was not statistically significant. All radiological measurements improved significantly in both groups without a statistically significant difference between the two groups. Conclusion: Clinical and radiological outcome of arthroereisis is comparable to corrective osteotomies in young adolescents with symptomatic pes planovalgus deformity and can be a valid option in management of these cases, but long term follow up is needed. Also, consensus regarding the perfect age, implant removal, and the degree of talonavicular uncoverage that can be corrected by arthroereisis need further studies.