Factors influencing functional outcomes in united intertrochanteric hip fractures: a negative effect of lag screw sliding.

The purpose of this study was to investigate the factors influencing functional outcomes in elderly patients with united intertrochanteric fractures treated with hip nails and to ascertain whether decreased femoral offset due to lag screw sliding has a negative effect on functional outcomes in these patients. This retrospective study included 65 patients older than 65 years with united intertrochanteric fractures treated with hip nails. Functional outcomes were assessed using the Short Form-36 (SF-36) and a visual analog scale (VAS) 6 months postoperatively. Mean patient age was 77.8 years (range, 65-90 years); mean follow-up was 20.7 months (range, 12-38 months). More lag screw sliding occurred as bone mineral density (BMD) decreased. It was also greater in unstable fractures and acceptable reduction status. Less accurate reduction and greater lag screw sliding showed significant negative effects on most subscales of the SF-36, especially Physical Functioning and Role Physical. A significant positive correlation was observed between the extent of lag screw sliding and VAS. Lag screw sliding affected by fracture type, reduction quality, and BMD has a negative effect on functional outcomes in elderly patients with united intertrochanteric fractures. Therefore, the preservation of anatomical femoral offset as much as possible is needed to obtain better functional outcome through the minimization of lag screw sliding by more accurate reduction, which is a controllable factor, especially in osteoporotic unstable intertrochanteric fractures.