Treatment of Thumb Tip Degloving Injury Using the Modified First Dorsal Metacarpal Artery Flap

PurposeThis study reports repair of a thumb tip degloving injury using the modified first dorsal metacarpal artery (FDMA) flap, including both dorsal branches of the proper digital nerve (DBPDNs).MethodsFrom May 2006 to February 2008, the modified FDMA flap was used in 11 thumbs in 11 patients. All patients suffered a degloving injury to the thumb tip, and 4 had associated bone loss ranging from 1 to 3 mm (mean, 2 mm) in length. The size of the soft tissue defects was 2.6 to 4.6 cm (mean, 3.5 cm) in length and 1.8 to 2.2 cm (mean, 2.0 cm) in width. The flaps ranged in size from 2.7 × 2.2 cm to 4.8 × 2.1 cm (mean, 3.6 × 2.1 cm). The mean pedicle length was 7.2 cm (range, 6.8–7.5 cm). Neurorrhaphy between the DBPDN and the proper digital nerve was performed in both sides in all cases. Patient follow-ups ranged from 26 to 47 months (mean, 32 mo). Sensibility of the reconstructed thumb was evaluated by static 2-point discrimination. The range of motion of the donor fingers was measured. The data were compared to those of the opposite sides.ResultsAll flaps survived completely. At the final follow-up, the mean values of static 2-point discrimination were 5 mm (range, 4–8 mm) and 6 mm (range, 4–8 mm) on the radial and ulnar sides of the distal portion of the flap, respectively. The mean values of the radial and ulnar distal portions of the flaps reached 75% and 72% of those of the opposite sides. The mean range of motion of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints of the donor fingers were 73°, 101°, and 70°, respectively.ConclusionsThe modified FDMA flap, including both DBPDNs, is useful for restoration of sensation on the thumb tip and maintenance of adequate length of the thumb.Type of study/level of evidenceTherapeutic IV.