Anatomy of Distal Articular Surface of Hamate Bone, A Cadaveric Study

Background: Hemi-hamate arthroplasty is one of the treatment options for dorsal proximal interphalangeal joint fracture dislocation. Many studies reported favorable outcomes. However, some long term studies demonstrated the degenerative change of PIP joint. The articular mismatch of the hemi-hamate autograft might play an important role of this complication. Methods: We studied the anatomy of distal articular surface of the hamate bone in embalmed hamate bones. The anatomy of distal articular surface and dimensions of the hamate bone were measured and recorded. Results: Seventy hamate bones were dissected out from embalmed cadavers and included in this study. The mean angle of the 4^th metacarpal articulation was 85.54 degrees (SD = 3.53) and mean angle of the 5^th metacarpal articulation was 95.51 degrees (SD = 3.57). The inter-articular ridge was approximately 5 degrees radial inclination. Conclusions: The inter-articular ridge of distal articular surface was approximately 5 degrees radial inclination. In order to minimize the graft mismatch, we recommend making the bone cut with the saw blade tilted to radial side 5 degrees to achieve better alignment of inter-articular ridge of the graft.