Interpretation of Intra-Articular Distal Radius Fractures Using Zenithal Three-Dimensional Computed Tomography: A Reader-Based Comparative Study

Abstract To determine whether a zenithal three-dimensional computed tomography (3D CT) view with carpal subtraction improves interpretation of intra-articular distal radius fractures compared with radiographs (XR) and two-dimensional computed tomography (2D CT). We conducted a cross-sectional reader study with 20 attending hand surgeons who evaluated 5 intra-articular distal radius fractures. Each case was reviewed sequentially (XR → 2D CT → 3D CT). For each imaging modality, readers drew the perceived articular fragments on a standardized distal radius template and indicated the presence or absence of comminution. The reference fracture pattern was defined using a zenithal 3D CT view with carpal subtraction. The primary outcome was overall correct interpretation (OCI), defined as the combination of correct fragment number, correct spatial disposition, and correct identification of comminution. Secondary outcomes included each individual component and the proportion of true articular fragments identified. Overall OCI was substantially higher with zenithal 3D CT than with XR or 2D CT. Similarly, zenithal 3D CT significantly improved correct identification of fragment number and spatial disposition compared with both XR and 2D CT, whereas no relevant differences were observed between XR and 2D CT. Correct identification of comminution did not differ meaningfully across imaging modalities. The proportion of true articular fragments identified increased progressively from XR to 2D CT and was highest with zenithal 3D CT. Qualitative overlays showed minimal change from XR to 2D CT and a marked contraction toward the reference with 3D CT (notably in cases 1, 3, and 5). A zenithal 3D CT view with carpal subtraction improves global interpretive accuracy of intra-articular distal radius fractures, particularly for fragment number identification and spatial understanding, compared with XR and 2D CT. These findings support the use of zenithal 3D CT for fragment-specific preoperative planning in complex articular distal radius fractures.