[Comparation of outcomes of iliac crest bone graft and accessory navicular bone graft in the Cotton osteotomy for pediatric and adolescent flexible flatfoot].

To compare the outcomes between iliac crest and accessory navicular as different bone grafts in the Cotton osteotomy in the treatment of pediatric flexible flatfoot deformity. A retrospective cohort study. The clinical data of pediatric flexible flatfoot patients with symptomatic accessory navicular received operations from July 2018 to March 2022 in Beijing Tongren Hospital were retrospectively analyzed. All the patients were treated with Cotton osteotomy. According to the different sources of bone grafting in Cotton osteotomy, the patients were divided into iliac crest group and accessory navicular group. There were 12 patients (19 feet) in iliac crest group, including 9 males and 3 females with a median age (, ) of 11(11, 12) years and were followed-up for 36(6, 48) months. There were 9 patients (16 feet) in accessory navicular group, including 6 males and 3 females, with a median age (, ) of 11(11, 11) years and were followed-up for 12(6, 17) months. Radiographic evaluations were reviewed and compared between the two groups before surgical treatment and at final follow-up, included talo-1st metatarsal angle (T1MT), talonavicular coverage angle (TNCA), talocalcaneal angle (TCA) in weight bearing anteroposterior view, and Meary angle, calcaneal Pitch angle, Kite angle, cuneiform articular angle (CAA) in weight bearing lateral view, and hindfoot alignment angle (HAA) in calcaneal long axial view. Functional scores included American Orthopedic Foot and Ankle Society (AOFAS), visual analog scale (VAS), and Maryland scores were recorded and compared before and after the operation. The complications were also recorded. Total of 21 patients were successfully followed in this study. The radiographic measurements in the two groups, such as T1MT, TNCA, Meary angle, Pitch angle, Kite angle, CAA, HAA, were all significantly improved at the last follow-up when compared with those before the surgery (all <0.05); and the AOFAS, VAS, Maryland scores in both groups were all improved after the surgery (all <0.05). There was a significant difference in CAA alteration (∆CAA) after the operation between the two groups, the ∆CAA in iliac crest group and the accessory navicular group was 6.0°±2.6° and 4.3°±1.3°, respectively (=0.017). There was no significant differences in the improvement of other radiographic measurements between the two groups (all >0.05). All the patients had a successful bone union. Two patients had donor site pain in the iliac crest group and were treated conservatively. Compared with iliac crest bone graft, accessory navicular bone graft could achieve comparable outcomes in radiographic measurements and functional scores in the treatment of pediatric flexible flatfoot with accessory navicular pain.