Enoxaparin and Early Postoperative Tibial Nailing: Increased Nonunion Revision Rates

Abstract

To determine the association between postoperative enoxaparin use and the risk of requiring surgery for nonunion in patients treated with intramedullary nailing for midshaft fractures of the tibia. Design: Retrospective cohort analysis. Data were sourced from the PearlDiver national database. Patients were identified through the PearlDiver database by using CPT and ICD-10 codes. Included patients had undergone intramedullary nailing for midshaft fractures of the tibia between 2015 and 2020 and subsequently underwent revision surgery due to nonunion. The primary outcome measured in this study was rate of nonunion following intramedullary nailing for the different types of tibial shaft fractures (closed, Type I/ II open, Type III open). For each fracture subtype, the study compared nonunion rates between those who received enoxaparin in the postoperative period and those who did not receive enoxaparin at any time during the first six weeks postoperatively. Factors such as the timing and duration of enoxaparin therapy and demographic variables were also considered. The study included 16,986 patients, average age 49.2 years (SD 17.3); 43.1% were female. 574 patients required revision surgery for nonunion (3.4%). Among patients who did not receive enoxaparin, the nonunion rates were 1.6%, 3.9%, and 6.9% for closed, Type I/II open, and Type III open fractures. For patients who received enoxaparin within the first two weeks, the nonunion rates were 2.6%, 4.7%, and 7.9% for closed (RR = 1.67, p < 0.0001), Type I/II open (RR = 1.21, p < 0.0001), and Type III open (RR = 1.17, p = 0.355) fractures. Logistic regression confirmed enoxaparin was independently associated with nonunion (OR = 1.75, p = 0.0013 for closed fractures; OR = 1.51, p = 0.034 for Type I/II open fractures). Tobacco use was also a contributing factor (OR = 2.43, p < 0.0001 for closed fractures; OR = 2.00, p < 0.0001 for Type I/II open fractures; OR = 2.04, p = 0.0008 for Type III open fractures). The postoperative use of enoxaparin was associated with an elevated risk of nonunion in patients treated with intramedullary nailing for fractures of the tibial shaft. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.