Abstract
<title>Abstract</title> <p> <bold>Background</bold> Severe thermal-crush injuries of the hand are challenging due to progressive tissue necrosis that evolves over days, making the optimal timing of definitive soft tissue coverage controversial. While early flap coverage within 72 hours is established for sharp extremity trauma, it may be suboptimal when tissue viability is initially uncertain. We compared functional outcomes between intentional staged debridement followed by delayed microvascular reconstruction and early flap coverage in these injuries. <bold>Methods</bold> In this prospective cohort study conducted at a tertiary referral center (2022–2024), 64 patients with Grade IIIB/IIIC hand thermal-crush injuries (Mangled Extremity Severity Score [MESS] < 7) were enrolled. Based on shared decision-making, 32 patients underwent staged debridement followed by delayed free gracilis muscle flap reconstruction (study group) and 32 underwent early flap coverage within 72 hours (control group). All patients received emergency fasciotomy and standardized postoperative rehabilitation. Primary outcomes at 24 months were total active motion (TAM), QuickDASH score, grip strength (% of contralateral), and protective sensation (4.31 g monofilament detection). Secondary outcomes included complications, secondary surgeries, and return-to-work. Multivariable regression identified predictors of favorable outcome (TAM ≥ 200°). Minimum follow-up was 24 months (94% complete). <bold>Results</bold> Baseline characteristics were comparable between groups. Time to reconstruction was 14.2 ± 2.8 days in the staged group versus 2.8 ± 0.6 days in the early group (p < 0.001). At 24 months, the staged group demonstrated superior outcomes: TAM (218° ± 24° vs. 184° ± 28°; mean difference 34° [95% CI 20° to 48°]; p < 0.001), QuickDASH (24.5 ± 8.2 vs. 38.2 ± 10.4; mean difference − 13.7 [95% CI -18.5 to -8.9]; p < 0.001), grip strength (51% ± 9% vs. 41% ± 11%; mean difference 10% [95% CI 5% to 15%]; p < 0.001), and preserved protective sensation (97% vs. 83%; odds ratio 6.6 [95% CI 1.2 to 36.8]; p = 0.04). Flap survival was similar (97% vs. 93%; p = 0.42). The staged group had lower rates of tendon adhesion (10% vs. 27%; p = 0.04), joint stiffness (13% vs. 30%; p = 0.04), and secondary surgeries (17% vs. 37%; p = 0.03). Return to pre-injury occupation was achieved in 77% of staged patients versus 53% of early patients (p = 0.03), with shorter mean time to return (6.8 ± 1.5 vs. 9.2 ± 2.1 months; mean difference − 2.4 months [95% CI -3.3 to -1.5]; p < 0.001). Delayed reconstruction independently predicted favorable functional outcome (odds ratio 3.2 [95% CI 1.4 to 7.1]; p = 0.005). <bold>Conclusions</bold> Intentional staged debridement followed by delayed microvascular reconstruction significantly improves long-term functional outcomes, reduces complications, and enhances return-to-work rates compared with early flap coverage in patients with severe hand thermal-crush injuries. These findings support delayed reconstruction as the preferred strategy for this challenging injury pattern. <bold>Level of Evidence:</bold> Level II, therapeutic study. </p>