Adolescent lower-limb postural abnormalities encompass physiological alignment variation, impaired dynamic motor control, and structural deformity, which require different intervention goals and standards of evidence. This review classifies flexible wearable lower-limb systems into motor-cable, pneumatic artificial muscle, elastic-element, and smart-material technologies, and compares the assisted joints, mass boundaries, power supply, sensing and control, and human-subject findings. Direct evidence in children and adolescents is distinguished from mixed-age evidence and technology transferred from adult populations. Current studies mainly support gait assistance, improved walking economy, and rehabilitation training. A small number of systems have been tested in children with cerebral palsy, but the evidence is insufficient to show that flexible external traction can produce sustained correction of the osseous alignment associated with adolescent genu varum or genu valgum. Motor-cable systems facilitate force-feedback control, pneumatic systems are constrained by their air supply and response characteristics, elastic assistance depends on stiffness and gait-phase matching, and smart materials still present thermal, electrical, and durability challenges. Future adolescent-oriented systems should prioritize growth-adjustable sizing, low distal mass, measurable interaction forces, and fail-safe unloading. Their effectiveness should be evaluated through off-device retention of functional gains and long-term follow-up.