Does proximal femoral nail antirotation achieve better outcome than previous-generation proximal femoral nail?

BACKGROUND There are few studies in the literature comparing the clinical outcomes and radiographic results of proximal femoral nail(PFN)and proximal femoral nail antirotation(PFNA)for pertrochanteric femoral fracture(PFF)in elderly patients.AIM To evaluate both clinical and radiographic outcomes after fixation with PFN and PFNA in an elderly patient population.METHODS One hundred fifty-eight patients older than 65 years with PFF who underwent fixation with either PFN or PFNA were included.Seventy-three patients underwent fixation with PFN,whereas 85 were fixed with PFNA.The mean follow-up was 2.4 years(range,1-7 years).Clinical outcome was measured in terms of operation time,postoperative function at each follow-up visit,and mortality within one year.Radiographic evaluation included reduction quality after surgery,Cleveland Index,tip-apex distance(TAD),union rate,time to union,and sliding distance of the screw or blade.Complications including nonunion,screw cutout,infection,osteonecrosis of the femoral head,and implant breakage were also investigated.RESULTS Postoperative function was more satisfactory in patients who underwent PFNA than in those who underwent PFN(P=0.033).Radiologically,the sliding difference was greater in PFN than in PFNA patients(6.1 and 3.2 mm,respectively,P=0.036).The rate of screw cutout was higher in the PFN group;eight for PFN(11.0%)and two for PFNA patients(2.4%,P=0.027).There were no differences between the two groups in terms of operation time,mortality rate at one year after the operation,adequacy of reduction,Cleveland Index,TAD,union rate,time to union,nonunion,infection,osteonecrosis,or implant breakage.CONCLUSION Elderly patients with PFF who underwent PFNA using a helical blade demonstrated better clinical and radiographic outcomes as measured by clinical score and sliding distance compared with patients who underwent PFN.

Comparative biomechanical study of reversed less invasive stabilization system and proximal femoral nail antirotation for unstable intertrochanteric fractures

Objective Unstable intertrochanteric fractures （ITFs） are mostly treated by proximal femoral nail antirotation （PFNA）,Inter-Tan,Asian Hip,and other new internal fixation devices.But for complex unstable fractures,such as crushed lateral wall of the greater trochanter,the loss of fixation point on lateral wall slightly reduces the fixing effect.This study aimed to compare the biomechanical strengths between reversed less invasive stabilization system （LISS） and PFNA for treatment of unstable ITFs.Methods Forty synthetic femurs were used to simulate unstable ITFs in vitro and were fixed using the reversed LISS or PFNA.These fractures were divided into two groups depending on whether the lateral wall of the greater trochanter is intact or not （AO classification：31-A2.3 and 31-A3.3,respectively）.The load-displacement of femur,stiffness,ultimate load,and cyclic fatigue resistance were detected using an incremental load test and a dynamic fatigue test through an MTS 858 test system.Results For both 31-A2.3 and 31-A3.3,the vertical sinking displacement （VSD） of the femoral head under 500 N load was insignificantly smaller after treatment with reversed LISS than with PFNA,and when the displacement was 5 mm,the femoral head bore insignificantly greater load.The fixation with reversed LISS resulted in greater axial stiffness of the femur but smaller ultimate load.During the same cycle in the dynamic fatigue test,the VSD was insignificantly smaller with the fixation of reversed LISS.Conclusion Reversed LISS and PFNA have similar biomechanical strength for unstable ITFs.This conclusion should be supported by additional large-size research on basic biomechanics and clinical application.This is the first comparative biomechanical study comparing reversed LISS and PFNA for unstable ITFs.