Causes of Failure of Subtrochanteric Fracture Fixation, Systematic Review and Meta-Analysis

Abstract Background Subtrochanteric (ST) femoral fractures is defined as fractures of proximal femoral shaft that is located within 5 cm of the lesser trochanter. Any internal fixation device for trochanteric fractures is subject to significant concentrated bending stresses, leading to implant fatigue and fixation failure. Fixation of sub-trochanteric femoral fracture is considered a critical challenge. Objective To assess causes of failure of sub-trochanteric fracture fixation. Methods This meta-analysis study included 12 papers which included 999 patients, fixation failed in 163 patients. The included studies mentioned approximately 7 causes for fixation failure which included deep infection (in 2 studies), delayed union (in 2 studies), non-union (in 6 studies), screw cut-out (in 3 studies), Poor reduction (in 3 studies), implant breakage (in 4 studies) and varsus deformity /malrotation (in 3 studies). Results This study included 12 studies recruited 999 patients with sub- trochanteric femoral fracture, fixation was failed in 163 patients. The incidence of sub-trochanteric fixation failure was 17% in all included studies 62% of patients with fixation failure were smokers The incidence of fixation failure after intramedullary fixation was lower than after extra-medullary fixation. The incidence of fixation failure after open surgery increases 2.41 times compared with closed surgery. The incidence of fixation failure was higher in patients with post- operative hip varus compared with patients without post-operative hip varus. Conclusion The incidence of sub-trochanteric fixation failure was 17%. The causes for fixation failure included smoking, poor reduction, nonunion, implant breakage, screw cutout, varus deformity, extra-medullary nailing.