Vascularized hemi-hamate graft: Anatomic description of a novel pedicled osteo-chondro-ligamentous flap for proximal scaphoid reconstruction

Abstract

Scaphoid proximal pole destruction remains a surgical challenge owing to its high propensity for nonunion and osteonecrosis. The hemi-hamate graft has shown promising results in addressing this issue. However, long-term results of non-vascularized composite grafts remain uncertain. The purpose of this study was to investigate the feasibility of a vascularized hemi-hamate osteo-chondro-ligamentous pedicled flap for the reconstruction of the proximal pole of the scaphoid. Thirty fresh cadaveric wrists were used to harvest the hamate proximal pole on the dorsal intercarpal arch. A loss of substance of the scaphoid proximal pole was simulated and the hamate flap was transferred. In 15 wrists, a canulated screw osteosynthesis was performed to assess donor site morbidity and carpus stability on post-osteosynthesis dynamic radiographs. This study suggests that the proximal hamate can be harvested pedicled on the dorsal intercarpal arch. The pedicle (average pedicle diameter 0.9mm, mean length 31.5mm) allowed tension-free graft placement in all dissections, except for one. The morphology of the graft was very similar to that of the scaphoid proximal pole and the palmar capito-hamate ligament allowed scapholunate ligament reconstruction in all dissections. This is the first study that describes the use of a pedicled flap to fully reconstruct the complex osteo-chondro-ligamentous anatomy of the scaphoid proximal pole. This vascularized hemi-hamate flap could facilitate better long-term preservation of cartilage biomechanical properties compared to non-vascularized grafts. Donor site morbidity requires further investigation before recommending clinical use.