Primary bone grafting with locked plating for comminuted distal femoral fractures: can it improve the results?

Abstract

Background Distal femoral fractures are challenging injuries. The thin cortex, wide medulla, extensive comminution, and articular extension make fixation difficult, with high rates of nonunion and implant failure. Fixation of such fractures with bridging plates relies on secondary healing with callus formation. Although locked plating has improved the fixation strength, recent studies substantiate the concern that the high stiffness of these constructs suppresses callus formation, contributing to a nonunion rate of up to 19% seen with periarticular fractures. The absence or delay of osseous union maintains the construct loaded with the possibility of implant failure or loss of fixation. Aim of the work To highlight the importance of primary bone grafting with distal femoral locked plates in fixation of comminuted distal femoral fractures in adults as a biological enhancer of early callus formation; adding a protective mechanical support - once integrated - to the construct against stresses that can cause non-union and/or implant failure due to the reported callus suppression with such constructs with high stiffness. Patients and methods This prospective study included 11 patients with closed, comminuted distal femoral fractures. Clinical and radiological evaluation was performed. Fractures were classified according to the AO-OTA system. Radiological results were evaluated according to the ASAMI radiological scoring system, whereas functional results were assessed according to Schatzker and Lambert criteria and the ASAMI functional scoring system. All fractures were fixed through the open lateral approach using locked plates with primary autogenous bone grafting in the comminuted area all around. Results All fractures united with a mean union time of 16.2 weeks. The functional outcome according to the used scoring systems was excellent in nine patients (81.8%) and good in two patients (18.2%). Thus, satisfactory results (excellent and good) were obtained in all cases of the studied group, with no cases developing nonunion or implant failure. Conclusion Adding primary autogenous bone grafting to the locked bridging construct can overcome the problem of deficient callus formation. It does not only induce rapid callus formation biologically, but also mechanically protects the construct - once integrated - against repetitive stresses that can cause varus collapse, nonunion, and implant failure.