Prophylactic Intramedullary Nailing Improves Safety of Femoral Lengthening in Congenital Femoral Deficiency

Background: Fracture of newly formed bone (the regenerate) after EF (External Fixator) removal is a serious complication of bone lengthening in Congenital Femoral Deficiency (CFD). This study aimed to determine whether prophylactic intramedullary nailing (IMN) at the time of EF removal reduces the risk of femoral fractures in CFD and to evaluate its safety. Methods: This retrospective comparative study included 53 CFD patients who underwent femoral lengthening (44 in the IMN group, 9 in the no-IMN group). We analyzed the incidence of fractures, infections, and unplanned surgeries. The predictive value of Fischgrund principles for fracture risk was evaluated. Results: The fracture rate was 11.3% (6/53). The IMN group had fewer fractures (6.8%) versus the no-IMN group (33.3%, p=0.054). Surgical treatment risk for femoral fracture was significantly lower in the IMN group (2.3% vs 33.3%, p<0.05). Despite complications in IMN group (4.5% infection rate and 4.5% nail malposition rate), the rate of unplanned surgery was lower versus the no-IMN group (11.4% vs 33.3%, p=0.12). Poor regenerate morphology (insufficient cortices) predicted femoral fractures after EF removal only in no-IMN group. Prophylactic nailing reduced the negative impact of poor regenerate morphology. Conclusions: Prophylactic intramedullary nailing is an effective strategy to prevent early femoral fractures and reduce the risk of unplanned surgery. Fischgrund principles are not useful to predict the risk of femoral fracture after prophylactic nailing.