AIM: High-energy ankle traumas often lead to extensive soft tissue loss and ligament damage, making reconstruction both challenging and crucial for restoring stability and function. This study evaluated the effectiveness of using a free anterolateral thigh (ALT) flap with a fascia lata extension for addressing complex soft tissue defects and repairing the deltoid ligament in complex post-traumatic ankle injuries. CASE PRESENTATION: A 38-year-old man was examined at the Plastic Surgery Unit three months after a motorcycle crash for reconstruction of a soft tissue defect and deltoid ligament repair. Clinical examination revealed a 3 × 5 cm soft tissue defect with bone exposure and ankle instability. Reconstruction was planned and performed using a free ALT flap with an extension of the fascia lata and a fascia lata graft for deltoid ligament repair. No complications of the flap and no clinical signs of local infection were observed. During the follow-up period of 12 months, the ankle stability and the gait were improved with a reduction in pain. RESULTS: No complications related to the flap or clinical signs of infection were observed postoperatively. During the 12-month follow-up period, the patient exhibited improved ankle stability, reduced pain, and enhanced gait. At the one-year follow-up, the patient achieved a satisfactory functional outcome with an American Orthopedic Foot and Ankle Society (AOFAS) score of 79 points. The reconstructed tissue demonstrated adequate coverage, and the deltoid ligament repair provided joint stability. While flap bulkiness necessitated minor debulking surgery, the aesthetic and functional outcomes were satisfactory, with the patient expressing high satisfaction at 15 months post-surgery. CONCLUSIONS: The ALT flap combined with fascia lata graft is a viable option for soft tissue loss and deltoid ligament injury in clinical cases. While the ALT flap offers numerous advantages, including ease of harvest, pedicle length, and versatility, its bulkiness may necessitate revision surgery. However, despite this drawback, the combination of ALT flap and fascia lata demonstrated positive outcomes in our patient, highlighting its effectiveness in providing adequate tissue coverage and repairing the deltoid ligament.