How (un)useful is the pelvic ring stability examination in diagnosing mechanically unstable pelvic fractures in blunt trauma patients?

Objectives: Our goal was to evaluate the utility of the pelvic ring stability examination for detection of mechanically unstable pelvic fractures in blunt trauma patients.

Methods: Retrospective chart review.

Results: We enrolled 1,502 consecutive blunt trauma patients and found 115 patients with pelvic fractures including 34 patients with unstable pelvic fractures (Tile classification B and C). Unstable pelvic ring on physical examination had a sensitivity and specificity of 8% (95% CI 4-14) and 99% (95% CI 99-100), respectively, for detection of any pelvic fracture and 26% (95% CI 15-43) and 99.9% (95% 99-100), respectively, for detection of mechanically unstable pelvic fractures. The sensitivity and specificity of pelvic pain or tenderness in patients with Glasgow Coma Scale >13 were 74% (95% CI 64-82) and 97% (95% CI 96-98), respectively for diagnosing any pelvic fractures, and 100% (95% CI 85-100) and 93% (95% CI 92-95), respectively for diagnosing of mechanically unstable pelvic fractures. The sensitivity and specificity of the presence of pelvic deformity were 30% (95% CI 22-39) and 98% (95% CI 98-99), respectively for detection of any pelvic fracture and 55% (95% CI 38-70) and 97% (95% CI 96-98), respectively for detection of mechanically unstable pelvic fractures.

Conclusions: The presence of either pelvic deformity or unstable pelvic ring on physical examination has poor sensitivity for detection of mechanically unstable pelvic fractures in blunt trauma patients. Our study suggests that blunt trauma patients with Glasgow Coma Scale >13 and without pelvic pain or tenderness are unlikely to suffer an unstable pelvic fracture. A prospective study is needed to determine whether a set of clinical criteria can safely detect or exclude the presence of an unstable pelvic fracture.