Angular malalignment after intramedullary nailing of femoral shaft fractures

Objectives: To determine factors associated with angular malalignment of fe moral shaft fractures treated with intramedullary nails and to determine di fferences in the incidence of angular malalignment based on fracture locati on, fracture comminution, and method of treatment (i.e., antegrade or retro grade). Design: Retrospective. Setting: Level I trauma center. Patients: Three hundred sixty patients with 374 femoral shaft fractures wer e identified from a prospectively obtained orthopaedic trauma database. Com plete sets of immediate postoperative anteroposterior and lateral radiograp hs were available for 355 (95 percent) of the 374 fractures. Intervention: Patients were treated with antegrade (183 cases) or retrograd e (174 cases) intramedullary femoral nailing. Main Outcome Measure: Goniometric measurements were made on all immediate p ostoperative radiographs to determine the coronal plane and sagittal plane angular alignments. A multiple linear regression statistical analysis was u sed to determine factors associated with increasing angular malalignment. T he incidence of malalignment was determined using more than 5 degrees of de formity in any plane as the definition of malalignment. Results: Proximal fracture location, distal fracture location, and unstable fracture pattern were associated with increasing fracture angulation (p < 0.001). Fracture location in the middle third, stable fracture pattern, met hod of treatment (i.e., antegrade or retrograde), and nail diameter were no t associated with increasing fracture angulation (p > 0.05). The incidence of malalignment was 9 percent for the entire group of patients, 30 percent when the fracture was of the proximal third of the femoral shaft, 2 percent when the fracture was of the middle third, and 10 percent when the fractur e was of the distal third. The incidence of malreduction was 7 percent for patients with stable fracture patterns and 12 percent for those with unstab le fracture patterns. Conclusions: Patients with fractures of the proximal third of the femoral s haft treated with intramedullary nails are at highest risk for malalignment . Proximal fracture location, distal fracture location, and unstable fractu re pattern are associated with increasing fracture angulation.