Incidence of Vacuum Phenomenon Related Intra-articular or Subfascial Gas Found on Computer-Assisted Tomography (CT) Scans of Closed Lower Extremity Fractures.

OBJECTIVES:To determine the incidence of vacuum phenomenon related intra-articular or subfascial gas found on computer-assisted tomography (CT) scans of closed lower extremity fractures. DESIGN:Retrospective Review. SETTING:Level I Trauma Center. PATIENTS/PARTICIPANTS:A total of 153 patients with closed lower extremity fractures. INTERVENTION:CT scans of identified individuals were reviewed for the presence or absence of gaseous accumulations. MAIN OUTCOME MEASUREMENTS:The presence or absence of gas on CT. RESULTS:Twenty seven (17.6%) of the 153 fractures were found to have intra-articular or subfascial gas on CT despite clear documentation, indicating a closed injury with no significant skin compromise. Of the intra-articular fractures (OTA/AO 33B/C, 41B/C and 43B/C), 20% (23 of 113) were found to have gas on CT. All cases were associated with fracture of the tibia (P = 0.002). CONCLUSIONS:Computed tomography demonstrated the presence of intra-articular or subfascial gas in 17.6% (27/153) of closed lower extremity fractures and in 20% (23/113) of closed intra-articular fractures. The possibility of vacuum phenomenon must be considered when using this imaging modality as the confirmatory test for open intra-articular fracture or traumatic arthrotomy. LEVEL OF EVIDENCE:Level IV.