Review Question - QID 5733

The injury is best resurfaced with a reverse cross finger (RXFF) flap from the dorsum of the middle phalanx of the middle finger.

The RXFF is indicated for reconstruction of: (1) eponychial skinfold and coverage of an exposed extensor tendon near the IP joint, (2) sterile matrix nailbed defects with exposed distal phalanx, (3) contused, repaired, or grafted extensor tendon denuded of paratenon, (4) boutonniere deformity with poor-quality skin over the PIP joint after burn/avulsion injury, (5) complete avulsion of the nailbed, germinal matrix, and surrounding skin of digits. In such an injury of the index finger, the alternative procedure is a cross thumb to index flap, (6) elective correction of digital deformity. Ideal donor areas include the dorsal aspect of the middle and proximal phalanges of the adjacent fingers.

Atasoy (2016) revisits the RXFF. He describes cases of RXFF for eponychial loss, thumb reconstruction (resection of duplication), nailbed defect, exposed bare tendon laceration.

Atasoy (1982) described the original technique for RXFF. He states that the best donor site is the dorsum of the middle and proximal phalanges, and recommends avoiding the dorsum of DIP and PIP joints because of thinness of subcutaneous tissues in these regions.

Figure A shows full-thickness tissue loss from the nailbed including the sterile matrix, with exposed bone. Illustrations A and B shows resurfacing of the defect in Fig A with a RXFF from the dorsum of the middle phalanx of the middle finger.

Incorrect Answers
Answers 1 and 3: There is insufficient tissue over the distal phalanges of adjacent digits to allow creation of a RXFF large enough to cover the defects. In addition, using tissue from this region would lead to mobilization of the eponychium and leave the germinal matrix of the donor digit prone to injury.
Answers 2 and 4: The dorsum of the interphalangeal joints should be avoided because of thin skin/subcutaneous tissue.