The impact of transferred vascularized toe joint length on motion arc of reconstructed finger proximal interphalangeal joints: a cadaveric study

Vascularized toe joint transfer for finger proximal interphalangeal joint reconstruction can result in sub-optimal arc of motion and extension lag due to inappropriate intercalated bony segment length. We investigated the impact of intercalated segment length on passive arc of motion and extension lag of the reconstructed proximal interphalangeal joint. Cadaveric intercalated joint grafts were harvested from lesser toes and transferred to cadaveric fingers. The pre-determined finger proximal interphalangeal joint defect size was 2cm. Three different intercalated segment lengths were inserted and resulting proximal interphalangeal joint arc of motion and extension lag were measured. The average arc of motion of finger proximal interphalangeal joints was 81 degrees and 54 degrees for toe proximal interphalangeal joints. Long intercalated segments had an average arc of motion of 30 degrees with 32 degrees extension lag. Equal-length intercalated segments had an average 49 degrees arc of motion with 15 degrees extension lag. Short intercalated segments had an average arc of motion of 71 degrees with 8 degrees extension lag. Shorter intercalated segments provide the greatest reduction in extension lag.