Riordan pollicization for congenital absence of thumb, including greater trapezium, in an immature hand. A and B, Incision (see text). Skin of proximal phalanx (blue area in A) is elevated as full-thickness skin flap. C and D, Second metacarpal has been resected by dividing base proximally and by cutting through epiphysis distally, and finger has been relocated proximally and radially. Second metacarpal head has been anchored palmar to second metacarpal base and simulates greater trapezium (see text). E, Insertion of first dorsal interosseous has been anchored to radial lateral band of extensor mechanism of new thumb and origin to soft tissues at base of digit; insertion of first volar interosseous has been anchored to opposite lateral band and origin to soft tissues. SEE TECHNIQUE 80.29.