<b><i>Background:</i></b> Radical excision of debilitating hidradenitis suppurativa lesions is the only curative approach in the advanced stages of the disease. Different concepts for axillary reconstruction do exist, but data on their clinical outcome are scarce. <b><i>Methods:</i></b> This is a retrospective cohort study of two reconstructive methods (posterior arm flap vs. vacuum-assisted closure [VAC] + split-thickness skin graft [STSG]) for axillary defects in patients with severe axillary hidradenitis suppurativa treated at the University Hospital Zurich between 2005 and 2020. <b><i>Results:</i></b> A total of 35 patients (mean age 36 ± 10 years, mean BMI 29 ± 5 kg/m<sup>2</sup>, Hurley stage II–III) with 67 operated axillae were stratified according to their type of reconstruction. Median operation time in the flap group was 144 min (IQR 114–207) (cumulative 181 min [IQR 124–300]) and 50 min (IQR 40–81) in the VAC + STSG group (cumulative 151 min [IQR 94–194], <i>p</i> < 0.01; <i>p</i> = 0.20 [cumulative time]). The cumulative length of stay was 6 ± 3 days in the flap group and 14 ± 7 days in the VAC + STSG group (<i>p</i> < 0.01). Time to complete wound healing was 27 days (IQR 20–49) in the flap group and 62 days (IQR 41–75) in the VAC + STSG group (<i>p</i> < 0.01). Vancouver Scar Scale score was 6 (IQR 4–9) in the flap group and 11 (IQR 9–12) in the VAC + STSG group (<i>p</i> < 0.01). Protective sensory recovery was most satisfactory in the flap group (<i>p</i> < 0.01). Forty-four percent of patients of the VAC + STSG group demonstrated functional impairment of arm abduction. Time to return to work was less in group A with 42 days (IQR 27–57) needed as compared to group B with 48 days (IQR 34–55) needed (<i>p</i> = 0.32). The average cost saving was 25% higher for the flap group than for the VAC + STSG group. <b><i>Conclusion:</i></b> Despite an increased operation time, axillary reconstruction by the posterior arm flap yields a reduced length of stay, less time to complete wound healing along with restoration of a protective sensibility, and less axillary scarring avoiding functional deficits – eventually allowing earlier return to work.