A Comparison of Outcomes of Reconstruction of Palmar versus Dorsal Defects of the Thumb Using a First Dorsal Metacarpal Artery Flap with a Cutaneous Bridge Segment

Abstract

Background: The aim of this study is to compare outcomes of reconstruction of palmar versus dorsal defects of the thumb using the first dorsal metacarpal artery (FDMA) flap with a cutaneous bridge segment. Methods: All FDMA flaps done at our centre for reconstruction of traumatic thumb defects in the period from November 2017 to May 2019 were included in this study. Data with regard to the patient, the injury and the flap were recorded. The outcome measures recorded include flap survival, complications, duration of follow-up, static two-point discrimination (2-PD), cortical reorientation, paresthesia at the flap and donor site, pain at the flap and donor site, Kapandji score and aesthetic outcome. Results: The study included 11 patients with an average age of 35 years. All patients were men, and the injury involved the dominant thumb in seven patients. There were five dorsal defects and six palmar defects, and the average defect size was 7.22 sq cm. All flaps survived and there were no complications. The mean follow-up period was 15.2 months. The mean static 2-PD was 9.35 mm, cortical reorientation was complete in six patients, paresthesia score at the flap was 0.27 and at the donor site was 0.36. The visual analogue scale (VAS) pain for the flap was 1.09 and for the donor site was 1.27. The average Kapandji score was 8.64 and patients rated the aesthetic outcome of the flap at 8 and of the donor site at 7.36. There were no differences in outcomes between palmar and dorsal defects except for the aesthetic outcome of the flap that was rated better for dorsal defects. Conclusion: The FDMA flap designed with a cutaneous bridge segment provided reliable, single-stage reconstruction of dorsal and palmar thumb defects with good outcomes. Patients rated the aesthetic outcome of flaps used for dorsal reconstruction higher. Level of evidence: Level IV (Therapeutic)