Thumb reconstruction with a wrap-around free flap according to the level of amputation

In 1980, Morrison and O'Brien reported their experiences with the reconstruction of an amputated thumb using a wrap-around neurovascular free flap from the great toe, but its indication has been limited distal to the metacarpophalangeal (MP) joint (Morrison et al., J Hand Surg 5:575-583, 1980). We have performed 37 wrap-around free flaps from the great toe for the reconstruction of thumbs amputated at distal or proximal to the MP joint and investigated their functional results according to the level of amputation. The amputation was distal and proximal to the MP joint in 25 and 12 cases, respectively. Pinching and grasping power, two-point discrimination, and the amount of opposition to the other fingers were compared to the uninjured hand. Pinching and grasping power were not significantly different according to the level of amputation but the results of two-point discrimination was better in the cases amputated proximal to the MP joint. The opposition of reconstructed thumb to the other fingers was completely possible in all cases amputated distal to the MP joint. In the 12 cases amputated proximal to the MP joint of the thumb, opposition was completely possible in 6 cases in which the iliac bone block was fixated in the position of 30 degrees flexion and 45 degrees internal rotation. However, in the other six cases in the fixation of 30 degrees flexion and 30 degrees internal rotation, the opposition of the reconstructed thumb to the ring and little fingers was impossible in five cases and only to the little finger in one case. In this study, we concluded that amputation proximal to the MP joint is not an absolute contraindication to the wrap-around free flap procedure for thumb reconstruction. However, for a better functional outcome, we recommend iliac bone block fixation in the position of 30 degrees flexion and 45 degrees internal rotation.