Inter-relationships of Metacarpals 1 to 5, Regarding Their Length, Metaphyseal Midshaft Width, Articular Surface Area of Head and Base, Age, and Sex: A Cadaveric Study

Abstract

Background: Metacarpal factures are common, comprising up to 50% of hand fractures. More work is needed to further our understanding of metacarpal anatomy to improve fixation techniques and reduce postoperative complications following surgical implants. The purpose of this anatomic study was to evaluate the length, midshaft metaphyseal width, and area of the articular surface of the head (AH) and base (AB) of metacarpals 1 to 5. Methods: This prospective study assessed measures from 17 cadavers at 1 institution’s anatomy lab. The anatomic dimensions of the metacarpals in both the right and left hands were measured. Epidemiological data including sex and age at death were also collected. Results: In all, 29 hands were dissected for metacarpal anatomic measurements, for a total of 145 metacarpals. The second metacarpal was longest, at 69.58 mm. Multivariate analysis of variance revealed a significant effect of sex overall, with greater metacarpal dimensions in men. Increasing age was associated with decreasing dimensions, except for AH of metacarpal 1 (F = 3.43, P = .02) and AB of metacarpal 1 (F = 11.54, P < .001) and 4 (F = 4.21, P = .01). Multiple metacarpal dimensions were also significantly correlated with each other. Conclusion: Our data reveal further information regarding metacarpal dimensions of length, midshaft width, and AH and AB. The results allow for potential to improve surgical management through improving metacarpal implants, developing an optimal plate and screw design, techniques to better accommodate anatomical differences based on age and sex, reducing postoperative complications and improving the standard of care.