Anne M.L. Meesters (Groningen / NL), Miriam Oldhoff (Groningen / NL), Nymke Trouwborst (Groningen / NL), Nick Assink (Groningen / NL), Joep Kraeima (Groningen / NL), Max Witjes (Groningen / NL), Jean-Paul de Vries (Groningen / NL), Kaj ten Duis (Groningen / NL), Frank F.A. IJpma (Groningen / NL)
Abstract text (incl. references and figure legends)
Introduction: In acetabular fracture surgery, conventional fracture gap and step-off measurements on single two-dimensional computed tomography (CT) slices are prone to inter-observer variability and do not fully represent displacement of multiple fracture fragments in different directions. This study aims to develop a three-dimensional (3D) measurement for acetabular fracture displacement, determine the inter- and intra-observer variability, and correlate the measurement with clinical outcome.
Material & Methods: Three-dimensional models were created for 100 patients surgically treated for acetabular fractures. The '3D gap area', the 3D surface between all the fracture fragments, was developed. All patients were approached and asked whether they underwent conversion to total hip arthroplasty (THA) in order to correlate the 3D measurements of fracture displacement to clinical outcome. The association between the 3D gap area and the risk of conversion to THA was determined by an ROC curve and a Cox regression analysis.
Results: The 3D gap area had an excellent inter-observer and intra-observer reliability. The preoperative median 3D gap area for patients without and with a THA was 1731 mm2 versus 2237 mm2. The median postoperative 3D gap area was 640 mm2 versus 845 mm2. The area under the curve was 0.63. The Cox regression analysis, adjusted for age and gender, showed that a preoperative 3D gap area >2103 mm2 and a postoperative 3D gap area >1058 mm2 were independently associated with a 3.0 versus 2.4 times higher risk of conversion to a THA.
Conclusion: A 3D assessment of acetabular fractures is feasible, reproducible, and correlates with clinical outcome. Three-dimensional measurements could be added to the current classification systems to quantify the level of fracture displacement and to assess operative results.
Figure 1: Case example of a both-column fracture showing the discrepancy in measuring fracture displacement on different imaging modalities.
Disclosure: Do you have a significant financial interest, consultancy or other relationship with products, manufacturer(s) of products or providers of services related to this abstract? (If not, please enter "No" in the text field.)
No