The Radius of Curvature of the Inferior Distal Clavicle Is Similar to That of the Glenoid in Both the Axial and Coronal Planes and Similar to the Inferior Coracoid

Abstract

Purpose: The purposes of this study were to use computed tomography (CT) scans to compare the radius of curvature (ROC) of the inferior concave surface of the distal clavicle to the glenoid, determine graft dimensions, and compare the ROC of the congruent-arc distal clavicle autograft (DCA) to the congruent-arc Latarjet graft.

Methods: Patients who underwent bony glenoid reconstruction via a Laterjet procedure between January 2018 and January 2023 at a single institution were retrospectively identified. CT scans were used to measure the ROC of the glenoid on the axial and coronal sequences, measure the ROC of the distal clavicle on the sagittal oblique sequences, and determine the dimensions of the distal clavicle and coracoid graft.

Results: A total of 42 patients were included (Latarjet, n = 22; control, n = 20). The mean ROC of the inferior surface of the distal clavicle was not significantly different from the ROC of the glenoid in the coronal (P = .15) or axial planes (P = .65). The ROC of the coracoid when measured in the sagittal plane was not significantly different from the ROC of the distal clavicle (P = .25). The length, depth, and surface area of the coracoid in the congruent arc orientation were significantly larger than the distal clavicle (P < .005). Patients in the control group tended to have both a larger inferior clavicle ROC and a larger coracoid ROC compared to the Latarjet group (32.8 mm vs 29.6 mm, P < .0001; 31.8 mm vs 30.9 mm, P = .02).

Conclusions: The ROC of the inferior distal clavicle is similar to that of the glenoid in both the axial and coronal planes and similar to the inferior coracoid.

Clinical relevance: CT analysis reveals that the congruent-arc DCA technique provides a robust graft with dimensions that are suitable for reconstruction of the anterior glenoid.

Fig. 1

Multiplanar reconstruction was performed by manipulating the sagittal sequence (A) to measure the length of the coracoid (25.5 mm) (solid red line) from the tip to the elbow (red dotted line). The midsagittal view of the coracoid was found and the medial-lateral (13.9 mm) and superior-inferior (11.5 mm) thickness of the coracoid was measured on the corresponding coronal image (B).

Fig. 2

The midcoronal view of the clavicle was found and the width of the distal clavicle was held constant at 10 mm (A). The length of the clavicle (22.5 mm) was measured on the axial image at its midpoint (B). Multiplanar reconstruction was performed by manipulating the coronal sequence (C) to obtain an image perpendicular to the axis of the clavicle, providing a cross-sectional view of the clavicle that did not exceed 10 mm in length. The depth of the clavicle (11.5 mm) was then measured on the corresponding sagittal sequence (red line).

Fig. 3

Multiplanar reconstruction was used to identify the inferior glenoid rim (red line) on the coronal sequence, at which point the radius of curvature of the glenoid (27.0 mm) was measured on the corresponding axial sequence (A). Multiplanar reconstruction was used to identify the anterior third of the glenoid (red line) on the axial sequence, at which the radius of curvature of the glenoid (31.4 mm) on the coronal view was measured on the corresponding coronal sequence (B).

Fig. 4

The entire coracoid graft length was visualized on the sagittal oblique sequence and the radius of curvature of the inferior surface of the coracoid was measured (33.5 mm) (A). Multiplanar reconstruction was used to identify the inferior surface of the midpoint clavicle on the sagittal oblique sequences at a length that did not exceed 10 mm; radius of curvature of the distal clavicle was then obtained (32.0 mm) (B).

Fig. 5

Postoperative axial computed tomographic scan of a glenoid reconstruction with congruent-arc distal clavicle autograft revealing the similarities of radius of curvature and the reconstruction of the glenoid concavity.