Fate of Patients With a "Surprise" Positive Culture After Nonunion Surgery.

OBJECTIVE

Review the impact of unexpected positive cultures from definitive surgery for nonunion regarding postoperative treatment and ultimate result.

DESIGNS: Retrospective multicenter case series.

SETTING

Three level-one trauma centers.

PATIENTS: Six-hundred sixty-six consecutive nonunions were treated during the study period. Four-hundred fifty-three cases (68%) were considered at risk for indolent infection (prior open fracture, surgery, or infection) and had cultures taken at the time of definitive surgery.

INTERVENTION: Intraoperative cultures during definitive operative treatment of nonunions.

MAIN OUTCOME MEASUREMENT: The incidence of "surprise" positive cultures was determined, and the course of the patients was documented including the use of antibiotics, surgery performed, and the outcome regarding infection and union.

RESULTS

Ninety-one (20%) cases had a surprise positive culture despite negative inflammatory markers. Most of bacteria isolated from the cultures were Staphylococcus species. Eight (9%) of the ninety-one cultures were considered probable contaminants and no antibiotics were given, 5 of these patients healed. The other 83 patients were treated with antibiotics, initially 66 (80%) healed and 12 (14%) remained infected. Eighty-two percent of patients with augmentation healed as compared with 86% of those not grafted.

CONCLUSIONS

The treatment of nonunions is challenging, and in patients with a history of surgery or open fracture, we found that 20% had positive intraoperative cultures from the definitive surgery. We recommend intraoperative cultures for all patients undergoing revision surgery. The use of culture-specific antibiotics is justified based on the overall low rate of infection in this complex population and the high rate of chronic infection (25%) for those treated as contaminants. Patients may be counseled that a positive culture after nonunion surgery is a treatable problem but does increase the risk of infection and additional surgery as compared with those with a negative intraoperative culture.

LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.