This is a polytrauma scenario: chest trauma, transient haemodynamic instability and bilateral femoral plus tibial fractures. The orthopaedic strategy hinges on the patient's physiological status.
Damage-control orthopaedics (DCO) - for an unstable patient - means rapid temporary stabilisation (usually external fixation of all long bones) to limit blood loss and the inflammatory “second hit”.
Early total care / definitive fixation - for a stable patient - means proceeding to the best long-term construct.
The stem explicitly states the patient is haemodynamically stabilized, so we move to definitive fixation:
$\bullet$ Femoral shaft: closed intramedullary nailing is the established gold standard, allowing early weight-bearing and reliable union.
$\bullet$ Tibia: given the systemic insult and uncertain soft tissues, external fixation provides safe, low-burden stabilisation.
Plating the femur or external-fixing it as definitive care is suboptimal; choosing whatever is fastest is a DCO mindset for the unstable patient; ex-fixing every bone is only temporising.
\[\boxed{\text{IM nailing of both femurs} + \text{external fixation of both tibiae}}\]