Introduction: The Monteggia equivalent type 1b fracture, consisting of an ulnar shaft fracture and radial head dislocation, is a rare condition first described by Giovanni Battista Monteggia. The Metaizeau technique, emphasizing percutaneous intramedullary fixation to preserve bone healing and prevent growth plate damage, has gained prominence in managing these fractures. Case report: A 10-year-old boy presented with left forearm pain, swelling, and deformity following a fall while playing football. X-rays revealed a proximal fourth ulnar fracture with dorsal and lateral angulation, along with a proximal radial metaphyseal fracture showing anterior rotation and physeal extension. This fracture pattern resembled a Monteggia fracture type III but differed in the lateral proximal radial disruption via a Salter–Harris type II fracture rather than radial epiphysis dislocation. Satisfactory reduction achieved for ulna was managed with standard nailing system but could not be achieved for radial physeal injury, which was managed with Metaizeau technique. Discussion: Type 1b Monteggia equivalents involving a Salter–Harris type 2 fracture of the proximal radius with an associated proximal ulnar fracture, adherence to Monteggia fracture reduction principles is vital. Closed reduction and internal fixation are preferred treatments, with the Metaizeau technique offering advantages such as minimal invasiveness and avoidance of implant-related complications. The Metaizeau technique is particularly beneficial for displaced radial neck fractures in children, providing stable fixation while preserving the fracture environment necessary for optimal healing. Conclusion: In cases of Monteggia fracture equivalents, most proximal radial fractures typically reduce to an acceptable level following ulnar reduction. However, proximal radial physeal fractures may require specific attention to achieve satisfactory reduction. The Metaizeau technique, commonly employed in the management of isolated radial neck fractures, can be utilized to achieve this reduction to an acceptable level.