Background: Distal femoral fractures are challenging injuries. The thin cortex, wide medulla, extensive comminution and articular extension make fixation difficult with high rates of non-union and implant failure. Fixation of such fractures with bridging plates relies on secondary healing with callus formation. Although locked plating have improved the fixation strength, recent studies substantiate the concern that the high stiffness of these constructs suppresses callus formation, contributing to a non-union rate of up to 19% seen with peri-articular fractures. The absence or delay of osseous union maintains the construct loaded with possibility of implant failure or loss of fixation.
Aim of the work: To highlight the role 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 to the construct against stresses that can cause implant failure and non-union due to callus suppression.
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 while 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 9 patients (81.8%), good in 2 patients (18.2%). So, satisfactory results (excellent and good) were obtained in all cases of the studied group with no cases developed non-union or implant failure.
Conclusion: Adding primary autogenous bone grafting to the locked bridging construct can overcome the problem of deficient callus formation. It doesn't only induce rapid callus formation biologically, but also mechanically protects the construct - once integrated - against repetitive stresses that can cause varus collapse, non-union and implant failure.
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