Anatomic basis of ulnar index metacarpal reverse flow vascularized bone graft for index distal bone loss

Well-known advantages of vascularized bone grafts led us to determine the anatomical basis of a metacarpal vascularized bone graft to find a solution for distal index bone loss. Seventeen adult human hands from fresh cadavers were dissected and analyzed. For each hand, we studied the second dorsal metacarpal artery, the ulnar dorsal proper digital artery of index, and the ulnar palmar proper digital artery of the index. Location, diameters, origins, and anastomoses were observed, and at the end, the vascularised bone graft was raised. The second dorsal metacarpal artery was present in all hands, always arising from the dorsal carpal arch with a 1-mm mean diameter. The ulnar dorsal proper digital artery of index was isolated on all dissections, with a subcutaneous location on the ulno-dorsal side of the proximal phalanx. The mean diameter of ulnar dorsal proper digital artery at the level of index proximal phalanx was 0.4 mm. We found anastomotic branches between the ulnar dorsal and palmar proper digital artery of index at the level of the proximal phalanx which permitted us to elevate a vascularised bone graft. We succeeded in removing the graft in all specimens. Its pivot point was always more distal than the middle of the proximal phalanx. The arc of rotation allowed the graft to reach the distal phalanx in 80% of the cases. This anatomical study has demonstrated the theoretical possibility of a reversed pedicled bone graft taken from the ulnar neck of the second metacarpal. This graft brings the following benefits: (a) the use of a minor vascular axis, (b) a surgical technique with a dorsal approach allowing the elevation and the use of the graft at the same time. It can be used on the index for failures of DIP joint arthrodesis, huge chondroma, or traumatology.