Recep KARASU, Kadri YILDIZ
The European Research Journal - 2026;12(9):951-963
Objective: To evaluate the interobserver reliability of six radiographic angular measurements in pediatric and adult patients with flatfoot and to explore whether reliability differs between musculoskeletal radiologists and orthopedic foot-and-ankle surgeons. Methods: This retrospective cross-sectional study included 31 adults (mean [SD] age, 39.7 [9.1] years) and 32 pediatric patients (mean [SD] age, 10.5 [3.2] years; range, 8-14 years) with symptomatic flatfoot deformity. Six radiographic angular measurements (calcaneal pitch, talocalcaneal angle, talus-first metatarsal angle, talonavicular coverage angle, lateral distal tibial angle, and tibiotalar surface angle) were independently assessed on standardized weight-bearing radiographs by six observers (three musculoskeletal radiologists and three orthopedic foot-and-ankle surgeons) following four calibration sessions. Interobserver reliability was evaluated using the intraclass correlation coefficient (ICC) based on a two-way mixed-effects, absolute agreement model. Results: Calcaneal pitch, lateral distal tibial angle, and tibiotalar surface angle demonstrated moderate-to-good single-measure interobserver reliability (single-measure ICC, 0.69-0.76), indicating acceptable reproducibility for individual clinical use. When measurements from multiple observers were averaged, these parameters demonstrated excellent reliability (average-measure ICC > 0.90; 95% confidence interval [CI], 0.89-0.97). In contrast, talocalcaneal angle, talus-first metatarsal angle, and talonavicular coverage angle showed persistently poor reliability regardless of age (ICC < 0.50). Reliability patterns were broadly comparable between pediatric and adult groups. Exploratory subgroup analysis showed that radiologists achieved higher reliability for the lateral distal tibial angle and tibiotalar surface angle (ICC, 0.93-0.97) than orthopedic surgeons (ICC, 0.56-0.64). Conclusion: Calcaneal pitch, lateral distal tibial angle, and tibiotalar surface angle were the most reproducible radiographic parameters for flatfoot assessment across both age groups, whereas talocalcaneal angle, talus-first metatarsal angle, and talonavicular coverage angle demonstrated poor reliability, likely reflecting their greater geometric measurement complexity. The specialty-dependent reliability observed for the lateral distal tibial angle and tibiotalar surface angle suggests that cross-specialty calibration may be beneficial before orthopedic surgeons incorporate these parameters into routine clinical practice.
