Espinoza technique leads to excessive retroversion in piriformis fossa entry nailing: computed tomographic analysis.

Objectives: To evaluate whether aligning femoral rotation utilizing the intramedullary nail's inherent anteversion during antegrade femoral intramedullary nailing (Espinoza technique) is equally reliable through piriformis fossa (PF) and greater trochanter (GT) entry portals. Design: Retrospective computed tomography analysis. Setting: Level I Trauma Center. Patients/Participants: Adult patients without prior femur fractures or congenital femoral abnormalities and with prior computed tomography scans of the entire femur for indications unrelated to fractures. Intervention: Ideal femoral head screw trajectory was mapped by aligning the PF and GT entry points with the center of the femoral head. The angle between these lines and the distal femur posterior condylar tangent line was measured to demonstrate resultant femoral anteversion. Main Outcome Measure: The difference between these angles was compared to show the difference in femoral version between PF and GT entry nailing using the Espinoza technique to assess rotational fracture alignment. Results: Thirty femurs from 15 uninjured patients were evaluated. Mean rotational difference between GT and PF entry points was 15.8° ± 5.6° of additional retroversion with the PF entry point (P < 0.001). Conclusions: During PF entry nailing, application of the Espinoza technique can lead to an additional unplanned average of 16° of postoperative femoral retroversion due to the relatively posterior and medial location of the PF entry point. Use of the Espinoza technique may need to be restricted to GT entry nailing to prevent fracture malrotation.