title: Mid to distal third tibial shaft fractures caused by gunshots: Characterization and incidence of distal intra-articular extension.
abstract: BACKGROUND
  Spiral tibial shaft fractures are known to have a high rate of distal intra-articular extension; however, the risk of joint involvement caused by gunshots has not been thoroughly evaluated. The purpose of this study was to determine the incidence of intra- articular involvement in tibial shaft fractures caused by gunshots. The secondary purpose of this study was to assess the usefulness of ankle radiographs versus computed tomography (CT) scans in identifying these fractures.
  
  
  METHODS
  Ninety consecutive patients were identified as having a tibia fracture caused by gunshot at a Level-1 trauma center. Forty-four of these patients were fractures of the mid to distal third shaft. Twenty-eight patients had ankle CT scans available for review, and 24 patients had dedicated ankle films. Three orthopaedic surgeons and a radiologist read the radiographs and CT scans. Sensitivity and specificity analysis was performed for the ankle radiographs using ankle CT scans as the gold standard.
  
  
  RESULTS
  Seven of the twenty-eight fractures evaluated with a CT scan proved to have intra-articular involvement (Prevalence: 25%, 95% CI: 11.4%-45.2%). One of the seven intra-articular fractures was not seen on dedicated ankle radiographs (14.3%). The sensitivity of diagnosing an intra-articular extension on ankle radiographs was 0.85, 95%CI: 0.42-0.99. The specificity of diagnosing an intra-articular extension on ankle radiographs was 1.00, 95%CI: 0.81-1.00. Of the seven intra-articular fractures, three required additional treatment to address the intra-articular extension.
  
  
  CONCLUSIONS
  The incidence of intra-articular involvement for tibial shaft fractures secondary to gunshot is less than that reported for spiral type fractures (11-45% vs. 25-58%). Although radiographs have a high specificity, the sensitivity is lower than expected, with worse outcomes if a fracture is missed. We recommend that a CT scan should be utilized to determine intra-articular extension in the setting of tibial shaft fractures caused by gunshots.
authors.affiliation: Midwestern University, Department of Orthopaedics, 555 31st Street, Downers Grove, IL 60515, United States. Electronic address: charlie.lieder@gmail.com.
authors.forename: Charles
authors.initials: C
authors.lastname: Lieder
authors.affiliation: Rush University, Department of Orthopaedics, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Hellman
authors.affiliation: Rush University, Department of Orthopaedics, United States.
authors.forename: Bryan
authors.initials: B
authors.lastname: Haughom
authors.affiliation: Andrews Institute, Department of Orthopaedics, United States.
authors.forename: Jan
authors.initials: J
authors.lastname: Szatkowski
mesh_terms: D000293:Adolescent; D000328:Adult; D005593:Fracture Fixation, Internal / Q000379:methods; D017102:Fracture Healing; D006801:Humans; D015994:Incidence; D057072:Intra-Articular Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D014481:United States; D014948:Wounds, Gunshot / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D055815:Young Adult
keywords: Gunshot; Intra-articular; Shaft; Tibia fractures