Current Evidence of Digital and Hand Replantation Following Cold Ischemia or Cryopreservation: A Systematic Review

BACKGROUND: Digit and hand amputations are debilitating traumatic injuries associated with severely diminished quality of life. Although replantation is possible, it is logistically challenging due to the time sensitivity of these procedures. The upper limit of cold ischemia (4°C) for digit and hand replantation is 24 and 12 h, respectively. This review aims to summarize replantation outcomes following preservation below 4°C and/or beyond the ischemic limits. METHODS: The PubMed, Embase, Web of Science, and Scopus databases were searched from inception until December 2025 to identify all manuscripts reporting digit or hand replantation following preservation at ≤ 10°C or exceeding 6 h. RESULTS: Of 139 unique citations, 10 (n = 255 patients, 287 replantation) were included. The mean age was 29.7 ± 8.2 years. The duration of preservation was 6 to < 24 h (n = 242/287, 84.3%), 24 to < 36 h (n = 29/287, 10.1%), 36 to < 48 h (n = 8/287, 2.8%), 48 to < 96 h (n = 4/287, 1.4%), or 5 to 81 days (n = 4/287, 1.4%). Preservation temperature ranges included hyperthermic (≥ 38°C; n = 1/287, 0.3%), sub-normothermic (20°C to < 35°C; n = 84/287, 29.3%), cold ischemia (0°C to < 10°C; n = 197/287, 68.6%), high subzero (-20°C to < 0°C; n = 1/287, 0.3%), and cryopreservation (< -196°C to -80°C; n = 4/287, 1.4%). The overall replantation survival rate was 81.5% (n = 234/287). Two manuscripts reported four successful digit replantation cases following cryopreservation (-196°C) up to 81 days. CONCLUSION: Further investigation into modalities for extending digit and hand preservation times may improve outcomes, expand patient candidacy, and enable elective scheduling of digit and hand replantation.