Impact of femoral neck system removal after femoral neck fracture healing on biomechanical stability and screw stripping risk.

Abstract

This study aims to determine whether the removal of the femoral neck system (FNS) after bony union affects the biomechanical stability of the femur. Considering the technical challenges and potential complications, including screw stripping reported in recent studies, the study explores whether its removal impacts stress distribution within the femur and increases the risk of complications, such as screw stripping. The femurs were grouped into Intact, Group U (healed fractures with FNS in place), and Group R (healed fractures with FNS removed). Subgroup analysis was performed using Pauwels' classification for fractures at 30, 50, and 70 degrees. Finite element analysis (FEA) was used to model and evaluate the biomechanical behavior. Material properties for the models were derived from the literature. No significant difference in biomechanical stability was observed between Group U and Group R across the fracture angles tested, indicating that removal of FNS does not compromise the structural integrity of the femur. However, the risk of screw stripping during removal requires consideration. Removing the femoral neck system (FNS) after fracture healing preserves the femur's biomechanical stability, regardless of fracture angle. However, increased stress at the distal locking screw suggests caution to avoid complications such as screw stripping.