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.