Minimally Invasive Fassier-Duval Telescopic Rodding of the Lower Limb in Pediatric Osteogenesis Imperfecta: Current Evidence and Implications for Type I (Non-Deforming) Disease.

Osteogenesis imperfecta (OI) is the most common heritable bone-fragility disorder, with type I (non-deforming OI) representing its mildest classical phenotype (historically referred to as Lobstein disease). Intramedullary (IM) rodding is essential for managing recurrent long-bone fractures and progressive deformities, with the Fassier-Duval (FD) telescopic rod now being the standard choice. This narrative review, based on a structured search from the seminal 1959 description of IM rodding to 2026, synthesizes the design principles, the minimally invasive technique and the comparative outcomes of FD rodding of the lower limb, with explicit attention to type I disease. Across cohort studies, comparative series and a recent systematic review, telescopic rods consistently achieve lower revision rates and longer implant survival than static or non-telescopic devices, reducing reoperation odds by roughly three-quarters. Overall complication rates nonetheless remain high (commonly 33-55%) and are dominated by implant migration and failure of telescoping. Younger age and eccentric epiphyseal positioning after incomplete deformity correction increase migration risk. Type-I-specific evidence remains limited. A report published under the "Lobstein" designation involved a Sillence type IV patient and therefore does not constitute type-I-specific evidence. Retrospective data nevertheless suggest favorable implant survival with telescopic fixation, but definitive conclusions cannot yet be drawn. Proper technique, adjunctive bisphosphonate therapy and multidisciplinary care remain decisive. Phenotype-stratified prospective data are the principal unmet need.