This systematic review and meta-analysis of 39 studies found that subtalar arthroereisis is an effective treatment for pediatric flexible flatfoot, producing consistent improvements in pain, function, and radiographic alignment regardless of implant type. While both metallic and bioabsorbable implants yield similar overall outcomes and high patient satisfaction, bioabsorbable devices show slightly lower rates of implant-related complications—particularly persistent sinus tarsi pain and need for removal—though the evidence is limited and of low-to-moderate certainty due to a lack of high-quality comparative trials.