Background <p>This study compared the clinical efficacy of closed reduction with Kirschner wire (K-wire) intramedullary fixation versus bicortical fixation for pediatric distal radius metaphyseal-diaphyseal junction (MDJ) fractures.</p> Methods <p>We retrospectively analyzed 61 children with closed distal radius MDJ fractures admitted to the Affiliated Women and Children’s Hospital of Ningbo University between May 2021 and November 2024. Patients were divided into two groups according to the K-wire fixation method: intramedullary fixation group (IFG, 32 cases; K-wire without contralateral cortical penetration) and bicortical fixation group (BFG, 29 cases; K-wire with contralateral cortical penetration). We compared surgical time, fracture healing time, 6-month postoperative wrist function, and complication rates between groups.</p> Results <p>All 61 procedures achieved successful closed reduction; mean follow-up was 15.3 months (range: 6–24 months). Baseline data were comparable between groups. Surgical time did not differ significantly. Fracture healing time was shorter in the IFG. There were no significant differences in 6-month postoperative wrist function or overall complication rate between groups, although the complication rate was markedly lower in the IFG. No vascular, nerve, or tendon injuries, nonunions, or premature physeal closures occurred in either group during the follow-up period.</p> Conclusions <p>Closed reduction with K-wire fixation is an effective treatment for pediatric distal radius MDJ fractures. Compared with bicortical K-wire fixation, intramedullary K-wire fixation offers advantages including shorter fracture healing time and a trend toward a lower complication rate.</p>