A three-dimensional computed tomography study of the palmar ulnar corner fragment in distal radial fractures

Background Distal radius fractures are among the most common fractures, traditionally evaluated using two-dimensional (2D) parameters. These methods are unreliable in significantly displaced fractures, with discrepancies among evaluators. Recent advancements in imaging have introduced three-dimensional (3D) models, but standard parameters for 3D reduction morphology are not well established. This study aimed to develop a novel method for evaluating 3D reduction morphology based on the normal vector of a plane defined by anatomical reference points, comparing the reduction shape to the mirror image of the unaffected contralateral side. Methods This retrospective case-control study included 27 patients (mean age 67.6 years) who underwent osteosynthesis with a volar locking plate for distal radius fractures. Preoperative and postoperative computed tomography (CT) scans of the affected and unaffected wrists were analyzed using 3D image analysis software. The 3D coordinates of three reference points; (1) radial styloid process, (2) sigmoid notch volar edge, and (3) sigmoid notch dorsal edge, were used to evaluate the reduction shape and compare it to the unaffected side mirror image. Correlations between vector angles in the coronal, sagittal, and axial planes and clinical outcomes, such as % total active motion (%TAM) and Mayo wrist scores, were analyzed. Results The distances between the unaffected mirror image and postoperative image for the three reference points were 2.1 mm, 2.1 mm, and 2.7 mm, with barycenter differences of 1.7 mm. The postoperative plane areas consisted from three reference points were significantly larger in the postoperative image compared to the unaffected mirror image (203.4 mm² vs. 192.4 mm², P < 0.01). Correlation coefficients for vector angles in the yz-plane between unaffected mirror image and postoperative image were moderate (0.53, P < 0.05). Mild correlations were found between postoperative vector angles in the xy and xz planes and %TAM. Conclusions This novel 3D evaluation method provides a more comprehensive assessment of fracture reduction, particularly in the axial plane. While it demonstrates good reproducibility in coronal alignment, further refinement is needed for sagittal and axial alignments. This method could enhance surgical precision and improve clinical outcomes in distal radius fracture management. Clinical trial number: not applicable.

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A Novel Method to Represent the Three-Dimensional Inclination of the Distal Radius Joint Surface

Ikumi,

Asai,

Eda

et al. 2024

Preprint

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Background: This study aims to define three-dimensional (3D) parameters for the inclination of the distal radius joint surface. The goal is to develop standardized parameters for fracture reduction through comprehensive 3D evaluations of the joint surfaces. Methods: We analyzed 112 CT scans of unaffected wrists (56 males, 56 females) to construct 3D models of the distal radius. Using 3D coordinates, the normal vectors and angles were calculated based on three reference points on the distal radius joint surface. These normal vector components were then converted into unit vector components A, B, and C for the x, y, and z axes, respectively. Additionally, the angles of these unit vectors were assessed in the xy-, yz-, and xz-planes. The 3D measurements were compared between males and females and against traditional two-dimensional (2D) parameters such as palmar tilt and radial inclination. Results: For males, the unit vector components were A: -0.14 ± 0.09, B: -0.92 ± 0.02, and C: -0.36 ± 0.07; for females, A: -0.21 ± 0.08, B: -0.90 ± 0.03, and C: -0.36 ± 0.05. Significant differences were found between males and females for the A and B vector components (representing the palmar-dorsal and proximal-distal axes, P < 0.01). The angles of the unit vectors in the xy-, yz-, and xz-planes were 8.9 ± 5.4° / 12.9 ± 5.0°, 21.3 ± 4.1° / 22.1 ± 3.2°, and 22.2 ± 14.8° / 28.8 ± 10.1° for males and females, respectively. There were significant differences between males and females in the angles of the xy- and xz-planes (sagittal and axial planes, P < 0.01). Strong correlations were observed between the xy-plane vectors and palmar tilt (r = 0.96), as well as between the yz-plane vectors and radial inclination (r = 0.88). Conclusions: This study evaluated the 3D inclination of the distal radius joint surface, revealing significant gender differences. This method, which also allows for the assessment of rotational alignment—difficult with conventional techniques—is expected to be a key 3D parameter in treating distal radius fractures.

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A three-dimensional computed tomography study of the palmar ulnar corner fragment in distal radial fractures

Cited by 4 publications

References 29 publications

Morphologie ulnopalmarer Kantenfragmente bei distalen Radiusfrakturen

Morphologie ulnopalmarer Kantenfragmente bei distalen Radiusfrakturen

A Novel Approach for Three-Dimensional Evaluation of Reduction Morphology in Distal Radius Fracture

A Novel Method to Represent the Three-Dimensional Inclination of the Distal Radius Joint Surface

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