Background: The purpose of this study is to describe a novel technique using an interposition vein graft for thumb replantation in these severe avulsion injuries. Methods: From 2002 to 2012, 8 patients underwent interposition venous bridge grafting from the dorsal radial artery at the anatomic snuffbox to the ulnar digital artery of the thumb. All patients had a traumatic thumb amputation with a severe injury to the ulnar digital artery. The technique began with bony stabilization; the radial artery at the anatomic snuffbox is exposed, vein graft harvested, and microsurgical end-to-side (proximally) and end-to-end (distally) anastomoses are carried out. Results: The average time to the operating room was 7.4 hours and time to reperfusion was 9.5 hours. At 3.1 years of follow-up, all 8 thumbs remained viable, without any need for revision procedures. The only complication was a metacarpal shaft nonunion treated successfully with iliac crest bone grafting. At last follow-up, all patients reported no or mild pain, with an average metacarpophalangeal (MCP) range of motion of 46.5°, and intact but diminished 2-point discrimination. All patients were able to return to work full-time. Conclusions: Due to the challenging nature of thumb avulsion injuries and the pronated position of the thumb, novel salvage alternatives are important. We describe a technique when no proximal vessels are available, using a vein to bridge the dorsal radial artery to the ulnar digital artery of the thumb. This novel arterial reconstruction has shown promise in thumb replantation associated with severe avulsion injuries.