PEEK in Pediatric Calcaneal Lengthening: Alternative or Compromise? A Randomized Controlled Trial.

BACKGROUND

The optimal interposition material for lateral calcaneal lengthening osteotomy (LCLO) in pediatric flexible flatfoot remains uncertain. Iliac autogenous bone graft (AIBG) provides structural support but requires donor-site harvest; polyetheretherketone (PEEK) cages avoid a second incision.

METHODS

This randomized controlled trial included 60 unilateral feet in 60 patients allocated 1:1 to PEEK or AIBG. Weight-bearing radiographs were obtained preoperatively, immediately postoperatively, at 3 months, 6 months, 12 months, and final follow-up (minimum 24 months; mean 29 months). Six angles were assessed by two blinded observers. Longitudinal outcomes were analyzed using two-way repeated-measures ANOVA with Greenhouse-Geisser correction when required and Bonferroni-adjusted post-hoc comparisons.

RESULTS

Final American Orthopaedic Foot & Ankle Society (AOFAS) scores were 87.04±7.42 with PEEK and 88.31±6.56 with AIBG (p=0.489). All six angles showed their largest correction immediately postoperatively, followed by smaller changes in the same corrective direction. Time effects were significant, whereas treatment × time interactions were nonsignificant. Preoperative-to-immediate correction was significant for all angles; later changes were smaller. Union occurred in all feet. Composite complications were higher with PEEK (27% vs 3%; p=0.026).

CONCLUSION

PEEK and AIBG produced similar functional and radiological trajectories, but the higher complication rate (27% vs 3%) with PEEK supports further comparative evaluation. The results illustrate how structural correction can be distinguished from later remodeling when repeated radiographic measures are analyzed.