A nurse assessing a client who has multiple fractures in his left leg notes increasing edema. The nurse should recognize this finding as an early manifestation of which of the following complications?

Acute compartment syndrome is a serious complication of fractures caused by increased pressure within a closed muscle compartment, which compromises circulation and tissue perfusion. Early signs include increasing edema, pain disproportionate to the injury, and tightness of the compartment. As the pressure builds, the classic six P's may develop: pain, pressure, pallor, paresthesia, paralysis, and pulselessness. Increasing edema after multiple fractures of the left leg is a hallmark early warning sign that requires immediate intervention, as untreated compartment syndrome can lead to permanent muscle and nerve damage or necessitate amputation. Pulmonary embolism presents with sudden onset dyspnea, chest pain, and hypoxia — systemic rather than localized findings. Osteomyelitis is a bone infection that typically develops over days to weeks, presenting with fever, localized tenderness, and elevated inflammatory markers, not acute-onset edema post-fracture. Fat embolism syndrome, which can occur after long bone fractures, typically presents 24 to 72 hours post-injury with respiratory distress, petechial rash, and confusion — not simply localized edema. The localized, progressive swelling at the fracture site immediately points to compartment syndrome as the primary concern, making it the most appropriate answer.