BACKGROUND: This study aimed to evaluate the effect of low molecular weight heparin calcium (LMWH-Ca) on the prevention of deep venous thrombosis (DVT) in patients with anterolateral thigh (ALT) flap reconstruction.

METHODS: In total, 1001 patients with oral cancer who underwent ALT flap reconstruction were recruited. Based on the postoperative use of LMWH-Ca, the patients were divided into case (n = 633) and control groups (n = 368). The incidence of postoperative DVT was compared between groups.

RESULTS: There was no significant difference in DVT incidence between the two groups. Among patients older than 60 years, the incidence of lower limb DVT in the case group (0.813%) was significantly lower than that in the control group (8.108%, p = 0.012).

CONCLUSION: The postoperative use of LMWH in oral cancer patients with ALT flap transfer does not prevent the development of lower limb DVT. However, patients older than 60 years old benefited from the postoperative use of LMWH-Ca.