Quantitative measures of damage to subchondral bone are associated with functional outcome following treatment of displaced acetabular fractures.

Current analysis of displaced acetabular fractures is limited in its ability to predict functional outcome. This study aimed to (1) quantify initial acetabular damage following acetabular fracture through measurement of subchondral bone density and fracture lines, and (2) evaluate associations between acetabular damage and functional outcomes following fracture. Subchondral bone intensity maps were created for 24 patients with unilateral acetabular fractures. Measures of crack length and density differences between corresponding regions in the fractured acetabuli, normalized by the unfractured side, were generated from preoperative CT images. Damage measures were compared to quality of life survey data collected for each patient at least 2 years post-injury (Musculoskeletal Functional Assessment [MFA] and Short Form-36 [SF-36], with specific focus on parameters that best describe patients' physical health). CT image quantification of initial damage to acetabular subchondral bone was associated with functional outcome post-injury. In general, damage as quantified through differences in density in the superior dome region (zones 8 and 12) and the central anterior region of the acetabulum (zone 3) were found to be the strongest significant predictors of functional outcome (adjusted R(2) = 0.3-0.45, p < 0.05). Damage to the superior dome was predictive of worse functional outcome whereas damage to the central anterior region indicated a better functional outcome. Once automated, this approach may form a basis to score acetabular fractures toward improving clinical prognoses.