Septic Long Bone Nonunion Repair Outcomes Are Associated With Culture Organisms

To assess associations between cultured organism species and outcomes of septic long bone nonunion treatment.

Retrospective review.

Tertiary orthopaedic center.

Adult patients with septic long bone nonunion (OTA/AO ×1, ×2, ×3, ×4) repair at a single institution from 2014 to 2023 were retrospectively reviewed. Septic nonunion was defined as a nonunion associated with positive cultures, either a history of positive nonunion cultures from an outside hospital before study site presentation or a positive culture from nonunion surgery at the study site. Patients with incomplete data, <6 months follow-up without osseous union, or nonunion resulting from osteotomy, fusion, or pathologic fracture were excluded.

Initial injury and patient characteristics, surgical and antibiotic treatments, and cultured organisms were collected. Primary outcomes were unplanned operations after index nonunion repair to address infection or promote union, and ultimate union. Outcomes were analyzed by cultured organism species.

One hundred and one patients with septic nonunions were included. Mean age was 52 years (range 18-89) and 73% were male. Mean follow-up from definitive nonunion repair was 22 months (range 1.4-92.5). At final follow-up, 86% achieved radiographic union. Patients with negative index study site nonunion cultures (n = 20) were more likely to have at least 1 unplanned procedure versus patients with positive nonunion surgery cultures (n = 81); (60% vs. 30%, P = 0.018). Polymicrobial infections (in those with positive index study site nonunion cultures) were associated with double the rate of having at least 1 or more unplanned operation compared with monocolonized patients (43% vs. 18%, P = 0.014). No differences in union rates across bacterial species were observed ( P > 0.9).

In the current series, 86% of patients with septic nonunion ultimately achieved union. Specific cultured bacterial species was not associated with unplanned procedures or achievement of osseous union. However, polymicrobial infection was associated with more unplanned procedures to eradicate infection or promote union than monomicrobial infection. Polymicrobial septic nonunions may, therefore, require especially aggressive infection eradication efforts. Also, patients with negative cultures at time of index study site nonunion surgery were associated with a higher rate of unplanned procedures than those with positive cultures, emphasizing the importance of accurate culture data to guide antibiotic treatment regimens.

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.