OTA 1997 Posters - Pelvic & Acetabular Fractures

Failed External Fixation of Rotationally Unstable Pelvic Fractures in Obese Patients

Thomas M. Hupel, MD, Emil H. Schemitsch, MD, FRCS(C), Sergei A. Aksenov, MD, Michael D. McKee, MD, FRCS(C), James P. Waddell, MD, FRCS(C)

St. Michael's Hospital, Univ. of Toronto, Toronto, Ontario, Canada

Introduction: Patients with obesity undergoing surgery have an increased risk for post-operative complications. The purpose of this study was to determine the outcome of rotationally unstable pelvic fractures in obese patients, treated with initial external fixation.

Methods: Between the years of 1989 and 1995, 42 patients were identified, from a prospectively entered trauma data base, who had unstable fractures of the pelvic ring (Tile type B, OTA 61-B) treated with initial standard external fixation techniques. There were 22 males and 20 female patients with an average age of 33.3 years (range 14 to 70 years). All patients had significant other injuries with a mean Injury Severity Score (ISS) of 21 (range 9 to 41). The mechanisms of injury (MOI) included a MVA (n=32), fall (n=5), crush injury (n=2), train accident (n=2) and a boating accident (n=l). Fracture types included Tile B1.3 (n=13), B2.1 (n=19) and B2.2 (n=10). Patients with a Body Mass Index (BMI) greater than the 85th percentile were considered obese (BMI of 27.8 and 27.3 for males and females respectively). Ten patients were obese with a mean BMI of 32.9 (range 28-38.4) and the remaining 32 patients had a mean BMI of 22.8 (range 14-26) (p<0.001).

Results: Failure of external fixation occurred in 5/10 obese patients because of inadequate initial reduction of the symphysis pubis (n=3) or inability to maintain reduction (n=2). In the non-obese group 2/32 external fixators failed because of inadequate initial reduction in both cases. A higher incidence of failure occurred in the obese group (p<0.005). When only "open book" or Tile B1.3 type fractures were considered, failure of fixation occurred in 5/5 obese patients and 1/8 non obese patients (p<0.005). No failure of fixation occurred in obese patients with lateral compression (B2.1 or B2.2) pelvic fractures. There was no difference in the age, sex, MOI, or ISS (p>0.05), between the obese and the non obese groups. Symphyseal plating with one (n=2) or two (n=3) symphyseal plates was performed an average of 5.3 days (range 1 to 10 days) after failed initial external fixation. The mean residual symphyseal gap in the 5 obese patients, before symphyseal plating, was 5.2 cm (range 3-10 cm). At final follow up (mean 19 months, range 6-40 months) reduction was well maintained following symphyseal plating. All patients were fully weight bearing by 8 weeks and all fractures had united radiographically by 12 weeks without further complications.

Discussion/Conclusion: We report a significantly higher incidence of failure of primary extemal fixation for "open book" or Tile type B1.3 (CTA61-B1) pelvic fractures in obese patients. Early symphyseal plating maintained adequate reduction and achieved subsequent union in all cases of failed external fixation. Our study suggests that "open book" or type B1.3 pelvic fractures in obese patients may best be treated with primary symphyseal plating.