Anatomy of Hamate Articular Surface.

PURPOSE: To better understand variability in the articular anatomy of the distal hamate, particularly the central ridge angles (CRAs) and the radii of curvature.

METHODS

The surgically relevant features of the distal hamate include the CRA, the width of the articular surface, and the radius of curvature of each of its facets. In total, 118 CT wrists obtained between 2016 and 2020 were analyzed (63 men and 55 women with mean age of 64.8). Visage software was used to determine the width of the distal hamate articular surface in the coronal plane and the CRA as well as the radius of curvature of the fourth and fifth metacarpal facets in the coronal and sagittal planes. We also analyzed the fourth and fifth metacarpal facets to determine the incidence of a convex instead of a concave articular surface.

RESULTS

Analysis revealed variability in all measurements. The mean coronal articular width was 14.8 mm, whereas the mean CRA was 155°. With regards to the CRA, 10.2% had an angle > 1 standard deviation below the mean, and 14.4% had an angle > 1 standard deviation above the mean. The mean fourth metacarpal facet width was 6.6 mm compared to 8.9 mm for the fifth metacarpal facet. On the coronal plane, the majority of the fourth metacarpal facet was concave. However, for the fifth metacarpal facet, more than 50% were convex.

CONCLUSIONS

There is considerable variability in the general population with regards to the hamate distal articular surface.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.