Pediatric proximal femoral locking plate features superior biomechanical properties compared to those of multiple screws in fixing unstable pediatric femoral neck fractures

Pediatric femoral neck fractures result primarily from high-energy trauma. Common treatment methods include screw fixation and the placement of a proximal femoral locking plate. However, there is limited biomechanical evidence favoring one method over another for the treatment of unstable fractures. This study aimed to evaluate the biomechanical properties of screws and proximal femoral locking plates for the treatment of unstable pediatric femoral neck fractures using a synthetic bone model. Fourteen synthetic composite femurs were divided into two groups that included screw fixation (S) and locking plates (P). All specimens were prepared using a vertically oriented osteotomy to simulate unstable Delbet type II femoral neck fractures. Fixation in Group S employed three 6.5 mm cannulated screws, while Group P utilized a proximal femoral locking plate with 5.0 mm screws. The axial stiffness, cyclic elongation, and ultimate failure load were assessed using a universal material testing machine under standardized loading conditions. Statistical analyses were performed to compare biomechanical properties between the groups. Group P exhibited significantly greater axial stiffness (763 ± 212 N/mm) compared to that of Group S (547 ± 93 N/mm, P = 0.026). Following cyclic loading, elongation was significantly smaller in Group P (0.42 ± 0.2 mm) vs. Group S (0.88 ± 0.4 mm, P = 0.002). The ultimate failure load was also higher in Group P (2511 ± 321 N) than it was in Group S (2036 ± 256 N, P = 0.007). The failure modes differed, with Group S exhibiting screw bending and femoral neck collapse and Group P exhibiting subtrochanteric fractures. Proximal femoral locking plates offer superior biomechanical performance compared to that of screw fixation in unstable pediatric femoral neck fractures. These findings suggest that locking plates are a viable alternative to enhance stability and potentially reduce postoperative complications.