A surgical algorithm for the management of recalcitrant distal femur nonunions based on distal femoral bone stock, fracture alignment, medial void, and stability of fixation.

<bold>Background: </bold>Recalcitrant distal femur nonunions (RDFN) are a challenge in management due to factors including poor bone stock, multiple surgeries, metaphyseal bone loss, and joint contractures. There are no specific guidelines in the management of cases of RDFN. Based on our experience, we devised an algorithm and we present the results of 62 cases of RDFN managed following it.<bold>Materials and Methods: </bold>Our algorithm was formulated after analyzing 34 cases of RDFN and it involved four factors which were hypothesized to influence outcomes namely: distal femoral bone stock, extent of medial void, alignment of the fracture, and stability of fixation. Each factor was addressed specifically to achieve a good outcome. Between 2012 and 2015, 62 patients with RDFN at a mean age of 47.4 years (26-73) and 2.3 prior surgeries (2-6) were managed following the algorithm.<bold>Intervention: </bold>58 patients required revision osteosynthesis to improve alignment and achieve a stable fixation. 4 elderly patients with poor bone stock were managed with arthroplasty. Extent of medial void was found to significantly influence surgical decision making. Five patients without medial void required only cancellous autograft bone grafting, 47 patients with < 2 cm void were treated with an allograft fibular strut inserted in the metaphysis and 6 patients with a void > 2 cm were managed with medial plating.<bold>Outcomes and Results: </bold>57 patients treated with osteosynthesis achieved union at an average of 7.4 months (6-11) and the 4 patients managed with arthroplasty also had a favourable outcome. One patient who was managed with revision osteosynthesis had a nonunion with an implant failure and needed an arthroplasty procedure. The average LEFS (lower extremity functional score) of all our patients was 67 (51-76) at an average follow-up of 18.2 months (12-33).<bold>Conclusion: </bold>Our stepwise surgical algorithm would help surgeons to identify the factors that need to be addressed and guide them towards the interventions that are necessary to achieve a successful outcome while managing cases of RDFN.<bold>Level Of Evidence: </bold>III.<bold>Level Of Clinical Care: </bold>Level I Tertiary trauma centre. [ABSTRACT FROM AUTHOR]