This study was undertaken to document whether a basic set of a new unilateral external fixation device could provide sufficient stability in complex musculoskeletal injuries involving upper and lower extremities and in patients with unstable pelvic ring disruptions. The initial clinical evaluation was performed in Sweden (stage 1) followed by field evaluation at the Swedish Field Hospital during the Mogadishu conflict in Somalia (stage 2). In stage 1, there were 90 patients with 116 acute limb injuries and six patients with an unstable pelvic ring disruption. Ninety limb injuries and all six pelvic fractures were primarily stabilized by the external fixation device. The other 26 fractures were managed at the index operation with intramedullary nailing, open reduction, and internal fixation or cast immobilization. Twelve patients had a local pedicle or free vascularized flap for soft tissue coverage. One multiply injured with an open Gustilo IIIB tibial shaft fracture had an early amputation. The basic set provided adequate stabilization for soft tissue recovery in 89 limb injuries (89 of 90), thereby providing optimal conditions for continued management to skeletal consolidation in 88 patients. Hemodynamic stabilization was achieved in all six patients with unstable pelvic fractures. In stage 2, there were 63 patients with war injuries and 33 patients injured in traffic accidents. All were managed under field conditions. The basic set was sufficient for soft tissue recovery in all 96 cases. It is concluded that the rigidity of this device is adequate for stabilization of severe musculoskeletal injuries requiring major surgical procedures. In addition, the simplicity of this device, which allows for only a limited number of possible configurations makes it suitable for inexperienced surgeons working under war or mass-casualty conditions to manage these complex musculoskeletal injuries.