Burn boutonniere deformity (BBD) treatment remains a challenge in reconstructive surgery. Severe hand defects after burn/trauma may be reconstructed with nonsalvageable or amputated tissue. The fillet flap (FF) is generally used as “spare parts” in the trauma algorithm for mangled extremities. This case study examines the use of a FF with concurrent repair of the adjacent finger extensor tendon with the amputated finger flexor tendon after burn injury. The goal is to provide adequate tissue coverage using a finger FF while concurrently reconstructing the central slip of the extensor tendon with the transposed flexor tendon from an adjacent nonfunctional digit. After reconstruction, no subluxation of the extensor tendon occurred with manipulation. Despite prolonged rehabilitation due to injuries, the surgical site healed appropriately. Single-stage FF reconstruction with vascularized tendon grafts should be considered in selected patients with BBD. This novel idea can be applied to the management of traumatized extremities.