This study aimed to investigate the usefulness of force-controlled pelvic stress radiographs in the evaluation and treatment of fragility fractures of the pelvis (FFP) using a functional treatment strategy. We conducted a retrospective study of 55 geriatric patients with FFP who underwent pelvic stress radiographs on admission. The differences in the sacral width, pelvic ring width, and medial femoral head width between the radiographs with and without the Sam Sling II M size were defined as Δ sacral width, Δ pelvic ring width, and Δ medial femoral head width, respectively. We used Pearson's correlation test to assess the relationship between the degree of radiographic instability and the Johns Hopkins highest level of mobility scale (JH-HLM) at 10-days postadmission. Conventional receiver-operating-characteristic curve analysis was used to identify cases requiring surgery using the best cutoff value for radiographic instability. The JH-HLM was significantly correlated with Δ sacral width (r=-0.401, p=0.017), but not with Δ pelvic ring width (r=-0.298, p=0.080) nor with Δ medial femoral head width (r= -0.261, p=0.128). The best cutoff value of Δ sacral width in identifying surgical cases was 10.7 mm (sensitivity 75.0%, specificity 98.0%). Force-controlled pelvic stress radiographs could be helpful in assessing the need for surgery on admission.
Keywords: Johns Hopkins highest level of mobility scale; Sam Sling; fragility fracture of the pelvis; functional treatment strategy; stress radiograph.