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

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 0.9 mm, mean length 31.5 mm) 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.