Factors Associated With Development of Nonunion or Delayed Healing After an Open Long Bone Fracture: A Prospective Cohort Study of 736 Subjects

OBJECTIVES:To determine factors associated with developing nonunion or delayed healing after open fracture. DESIGN:Prospective cohort between 2001 and 2009. SETTING:Three level 1 Canadian trauma centers. PARTICIPANTS:Seven hundred thirty-six (791 fractures) subjects were enrolled. Six hundred eighty-nine (94%) subjects (739 fractures) provided adequate outcome data. INTERVENTION:Subjects were followed until fracture(s) healed; phone interviews and chart reviews were conducted 1 year after fracture. Patient, fracture, and injury information, and time to surgery and antibiotics were recorded during hospitalization. MAIN OUTCOME MEASUREMENTS:Nonunion defined as unplanned surgical intervention after definitive wound closure or incomplete radiographic healing at 1 year and delayed healing defined as 2 consecutive clinical assessments showing no radiographic progression or incomplete radiographic healing between 6 months and 1 year. RESULTS:There were 413 (52%) tibia/fibular, 285 (36%) upper extremity, and 93 (13%) femoral fractures. Nonunion developed in 124 (17%) and delayed healing in 63 (8%) fractures. The median time to surgery was not different for fractures that developed nonunion compared with those who did not (P = 0.36). Deep infection [Odd ratio (OR) 12.75; 95% confidence interval (CI) 6.07–26.8], grade 3A fractures (OR 2.49; 95% CI, 1.30–4.78), and smoking (OR 1.73; 95% CI, 1.09–2.76) were significantly associated with developing a nonunion. Delayed healing was also significantly associated with deep infection (OR 4.34; 95% CI, 1.22–15.48) and grade 3B/C fractures (OR 3.69; 95% CI, 1.44–9.44). Multivariate regression found no association between nonunion and time to surgery (P = 0.15) or antibiotics (P = 0.70). CONCLUSIONS:Deep infection and higher Gustilo grade fractures were associated with nonunion and delayed healing. LEVEL OF EVIDENCE:Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.