Clinical and Radiological Outcomes of Subtalar Kalix II Arthroereisis for a Symptomatic Pediatric Flexible Flatfoot

R.T.A.L. de Bot*, J. Stevens, J.P.S. Hermus, H.M. Staal, L.W. van Rhijn, A.M. Witlox

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background. The purpose of this study is to evaluate functional and radiological outcomes of subtalar arthroereisis in the treatment of symptomatic pediatric flexible flatfeet. Methods. A total of 16 patients (26 feet) were treated with a Kalix II as subtalar motion blocker between 2009 and 2014. Calcaneal pitch (CP) and Meary's angle (MA) were measured on radiographs preoperatively, directly postoperatively, and at follow-up 47 +/- 17 (range 19-79) months. Patient satisfaction surveys were used to assess functional outcome and patient satisfaction. Results. Surgery was performed mostly for pain, walking problems, or a combination of both at a mean age of 12.5 +/- 1.5 (range 10-15) years. Symptoms were relieved in 62.5% of patients in the postoperative phase and increased to 68.75% at follow-up. A statistically significant increase in CP of 2.8 degrees and decrease in MA of 14.0 degrees was observed directly postoperatively, which persisted during the follow-up period irrespective of Kalix removal. Revision surgery was necessary in 6 cases (23%) because of arthroereisis migration. Conclusion. Subtalar Kalix II arthroereisis significantly reduced clinical symptoms and improved the CP and MA directly postoperatively, which persisted during follow-up, irrespective of Kalix removal. Therefore, subtalar arthroereisis is a considerable intervention to reduce symptoms in children with symptomatic flexible flatfeet.
Original languageEnglish
Pages (from-to)9-18
Number of pages10
JournalFoot and Ankle Specialist
Issue number1
Publication statusPublished - 1 Feb 2021


  • symptomatic flexible flatfoot
  • subtalar arthroereisis
  • Kalix
  • pediatric patients
  • patient satisfaction
  • FOOT

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