Outcomes of nonunion repair for distal femur fracture nonunion.

Abstract

To report the outcomes aseptic distal femur nonunion repair and to identify factors associated with recalcitrant nonunion. Design: Retrospective cohort study. Single academic level 1 trauma center. All skeletally mature patients undergoing repair of a presumed aseptic distal femur nonunion (AO/OTA 33A or 33C) between 2005-2023 were eligible for inclusion. The primary outcome was the success of an initial nonunion repair attempt. Univariate and multivariable analysis was used to examine patient, injury, and treatment factors associated with recalcitrant nonunion. One hundred and two patients were included. Their average age was 56 (SD 15) and 64 were female. Forty-seven patients had open fractures and 60 patients had high energy mechanisms. Fifty three fractures were AO/OTA type 33A, while 49 were type 33C. The rate of recalcitrant nonunion was 23%. Diagnosis of fracture related infection (FRI) after the index nonunion repair was associated with increased risk of recalcitrant nonunion (47% with FRI vs 18% without FRI, p=0.021). Nonunion repair with a nail plate combination was significantly associated with decreased risk of recalcitrant nonunion (0/27, 0%) compared to repair with plate alone (8/28, 29%), nail alone (4/10, 40%), or graft alone (9/25, 36%), p<0.001. Looking at dual-column fixation constructs as a whole (including nail + plate, plate + endosteal plate or medial strut, dual-plate), fixation with a dual column construct was again associated with a lower rate of recalcitrant nonunion (1/36, 3%) compared to nail alone (4/10, 40%), plate alone (8/28, 29%), or graft alone (9/25, 36%), p<0.001. Nearly one in four patients developed a recalcitrant nonunion after attempted nonunion repair. Fixation with a dual-column construct was associated with decreased risk of recalcitrant nonunion. III.