Idiopathic Flatfoot in Children and Adolescents Treated with Arthroereisis—Muscle Recession May Not Be Necessary in Feet with Mild Gastrocnemius Shortening

<b>Background:</b> Arthroereisis is a well-accepted and relatively easy procedure to treat the flexible flatfeet in children and adolescents. A mild calf-muscle shortening is not seldom an accompanying feature. The need for a gastrocnemius recession in addition to arthroereisis is controversial. Therefore, the objective of this study is to investigate the need for a gastrocnemius recession in mild cases of gastrocnemius shortening to improve ankle dorsiflexion in addition to arthroereisis. <b>Methods:</b> Twenty-seven patients (ages 9-15 years) who underwent arthroereisis for painful idiopathic flatfeet were included in this non-randomised retrospective study, approved by Friedrich-Alexander University, Erlangen-Nürnberg (22-86-Br). The gait data of 18 typically developed children in same age group was used as reference. Based on the intraoperative Silfverskjöld test, two groups could be identified in the collective, one with shortened of gastrocnemius who underwent gastrocnemius recession (FFGR) and one without (FF). A control group included 18 feet of 18 typically developing children. Outcomes were evaluated by comparing pre- and postoperative clinical assessments including pain scores, gait analysis using a multi-segmental foot model, and radiological imaging. The mean follow-up was 22.1 months, and statistical analysis included a two-factor ANOVA. <b>Results:</b> No statistically significant differences in anthropometric, clinical, and gait parameters were observed between the groups preoperatively. Improvements in ankle dorsiflexion and pain were seen in both groups without statistical significance. There was no loss of calf-muscle strength or ankle power. <b>Conclusions:</b> Arthroereisis effectively corrects an idiopathic flexible flatfoot and reduces pain in children and adolescents. The gastrocnemius muscle stretches following arthroereisis and therefore, no lengthening is necessary when mildly shortened. The major limitations of this study are its retrospective nature, non-randomisation, and small size of the study collective.