Published in:
01-12-2012 | Clinical Research
Quantitative 3D-CT Anatomy of Hamate Osteoarticular Autograft for Reconstruction of the Middle Phalanx Base
Published in: Clinical Orthopaedics and Related Research® | Issue 12/2012
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Background
Hamate osteoarticular autografts are difficult to obtain and it is unclear to what degree the graft matches the joint surface to be replaced and whether a direct ulnar approach might provide a more reliable graft than the standard proximal to distal approach.
Purpose
We modeled hemihamate osteotomies using quantitative three-dimensional CT (3D-CT) to measure the amount of hamate articular surface used and the match with the native volar base of the middle phalanx.
Methods
In virtual hemihamate osteotomies (standard and direct ulnar) on CTs of 20 patients (11 men and nine women), we measured the percentage of hamate articular surface used for each finger, the match of the articular contour, and the percentage of hamate articular surface removed.
Results
The autograft in the standard approach used an average of 26% of the hamate articular surface and had an average 75% match of the articular contour with the volar half of the middle phalanx base. A direct ulnar approach removed an additional small margin of dorsal ulnar hamate with an average maximum width of 2.5 mm and volume of 27 mm3.
Conclusions
An osteoarticular allograft from the hamate to replace the volar half of the middle phalanx base uses less than 1/3 of the hamate articular surface even if the dorsal ulnar margin of the hamate is taken with the graft.
Clinical Relevance
These data suggest that it might be feasible to make the deep cut from a direct ulnar approach.