Injury patterns and outcomes of open fractures of the proximal ulna do not differ from closed fractures

Background: The incidence and injury patterns of open fractures of the proximal ulna are poorly elucidated and little evidence exists to guide management. Questions/purposes: The purpose of this study was to compare the (1) bony injury patterns; (2) range of motion (ROM) and frequency of union; and (3) postoperative complications between open and closed fractures of the proximal ulna. Methods: Seventy-nine consecutive open fractures of the proximal ulna were identified. After excluding fracture-dislocations, penetrating injuries, and pediatric injuries, 60 were compared in a retrospective case-control study with an age- and sex-matched group of 91 closed fractures to compare the bony injury patterns based on radiographic review. In a subset of 39 open and 39 closed fractures with sufficient followup, chart and radiographic review was performed by someone other than the operating surgeon to compare differences in final ROM, union, and postoperative complication rates at a minimum followup of 3 months (mean, 22 and 15 months; range, 3-86 months and 3-51 months for open and closed fractures, respectively). A total of 12% of the fractures were open (79 of 671) at the three study centers, and the majority of fractures were intraarticular (45 of 60 [75%]) with Gustilo-Anderson Type I and II wounds (54 of 60 [90%]). Results: Overall, open fractures of the proximal ulna overall did not have more complex bony injury patterns, but there were more anterior olecranon fracture-dislocations among the open fracture group (nine of 60 [15%] versus two of 91 [2%]; p = 0.004) and more posterior olecranon fracture-dislocations in the closed fracture group (31 of 91 [34%] versus seven of 60 [12%]; p = 0.002). Final ROM was not different in both groups and all fractures healed. There was no difference in wound infection rate but a higher secondary procedure rate among open fractures of the proximal ulna (39% versus 23%, p = 0.014). Conclusions: In contrast to open fractures of the distal humerus, open fractures of the proximal ulna present with mild soft tissue injuries and do not have more complex bony injury patterns than closed fractures. Our findings suggest that open fractures of the proximal ulna are the result of tension failure of the skin secondary to the limited soft tissue envelope around the proximal ulna. Open fractures of the proximal ulna should be regarded as relatively mild injuries that are not different in severity and prognosis compared with closed fractures. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence