[On-top plasty. Indications and technic in the reconstruction of severely injured hands]

The possibilities and advantages of the on-top plasty in the reconstruction of severely damaged hands are described. Based upon ten cases, a classification into four groups is made. In each of these groups different reconstructive procedures are applicable. Group 1: Intact thumb with loss of all fingers.

Lengthening of the third metacarpal by on-top-plasty of the distal half of the second metacarpal. This simultaneously widens the first intermetacarpal space. Group 2: Partial amputation of the thumb with severe damage to several fingers.

Thumb reconstruction by transposition of two phalanges of an otherwise useless finger. Group 3: Loss of the thumb and of two and a half fingers.

Thumb reconstruction by transposition of the remaining basal phalanx. Group 4: Loss of the thumb and of three fingers.

Thumb reconstruction by on top-plasty of the distal half of the metacarpals and rotational angulatory osteotomy of the fifth metacarpal.