Morphometric Assessment of the Residual Width of the Distal Hamate Articular Surface after Graft Harvest for Hemi-hamate Arthroplasty

Abstract

Background: The hemi-hamate arthroplasty (HHA) can restore joint congruity and stability in chronic fracturedislocations<br />of the proximal interphalangeal joint (PIPJ). Purpose of this study was to compare the width of the distal<br />hamate articular surface (DHAS) to the width of the base of the middle phalanges (P2) of the fingers. We hypothesized<br />the dimensions of the width of the DHAS would be similar to those of P2, leaving a small amount of residual DHAS<br />width after autograft harvest.<br />Methods: Fifty-nine CT scans of the hand without any bony pathology were evaluated. Three observers measured the<br />following parameters and compared: (a) Width of the DHAS in the axial and coronal planes; (b) Width of the P2 articular<br />bases of all four fingers; (c) Maximum capitate length (MaxCap) in the coronal plane.<br />Results: The residual DHAS on the coronal plane after graft harvest (bone remaining on the radial and ulnar aspects<br />each, not accounting for saw blade or osteotomy width thickness) among all patients was 1.3, 0.9, 1.4, and 2.4 mm for<br />the index, long, ring and small fingers respectively. There was a strong correlation between DHAS and MaxCap r=0.76.<br />Conclusion: There is likely to be a very small amount of residual hamate articular surface width left after the graft is<br />harvested if the entire base of P2 is reconstructed.<br />Level of evidence: III