Reconstruction of the subungual region for tumors of the thumb: Outcomes of the reverse, dorsoulnar flap.

Background For subungual, malignant skin tumors of the thumb, ultimate treatment has mostly been the amputation, a procedure that comes with a significant functional loss. We propose reconstruction of the defect with the reverse, homodigital, dorsoulnar, pedicled (RHDU) flap, if no osseous infiltration is present.Methods We present the cosmetic and functional results in five patients treated for subungual tumors of the thumb between May 2020 and September 2023. Range of motion in the metacarpo-and interphalangeal joints, the widening angle of the first web, Kapandji score, grip and pinch strength, outcome scores including the disability of the arm, shoulder and hand (DASH) and Michigan Hand Score (MHQ) were assessed at final follow up.Results Range for follow up was 1-5 years. Function was comparable to the contralateral side. Patient reported outcome showed satisfactory function with an average DASH score of 12.82 and MHQ score of 84.8. The cosmetic result was rated with an average of 90 points on the visual analogue scale for cosmesis. No recurrence of the tumor has been reported in any case.Conclusion Reconstruction of the defect with a RHDU flap after excision of subungual tumors and proof of no osseous invasion, is a reliable and a promising alternative to an amputation, resulting in satisfactory functional and cosmetic outcomes.