Regarding early complications of fractures, all of the following are true EXCEPT:

Explanation

## Early Complications of Fractures — Timeline & Incidence ### Classification by Onset **Key Point:** Early fracture complications occur within hours to days; late complications (infection, malunion, nonunion) develop over weeks to months. | Complication | Typical Onset | Mechanism | Frequency | |---|---|---|---| | **Hypovolemic shock** | Minutes–hours | Hemorrhage from fracture site & soft tissue trauma | Most common early complication | | **Fat embolism syndrome (FES)** | 24–72 hours | Marrow fat globules enter venous circulation after long bone fracture | 0.5–2% of long bone fractures | | **Compartment syndrome** | Hours–48 hours | Increased pressure within fascial compartment → tissue ischemia | Surgical emergency | | **Rhabdomyolysis** | Hours–days | Crush injury, prolonged immobilization → muscle necrosis → myoglobinuria | Risk of acute kidney injury | | **Pulmonary embolism (PE)** | Days–weeks | Venous stasis, endothelial injury, hypercoagulability | Peak incidence: 2–7 days post-fracture | ### Why Option 4 is Incorrect **High-Yield:** Pulmonary embolism is NOT the most common early complication of fracture. **Hypovolemic shock** from hemorrhage is the most frequent life-threatening complication in the immediate post-fracture period (first 24 hours). PE typically manifests at 2–7 days post-injury, not within the first 24 hours. ### Correct Options Explained **Option 1 (FES):** Classic presentation window is 24–72 hours; characterized by triad of hypoxemia, altered mental status, and petechial rash. [cite:Rockwood & Green's Fractures in Adults Ch 1] **Option 2 (Compartment syndrome):** Requires urgent fasciotomy within 6–8 hours to prevent irreversible muscle and nerve necrosis. Delay beyond 8 hours significantly increases morbidity. **Option 3 (Rhabdomyolysis):** Crush syndrome leads to myoglobin release → acute tubular necrosis → acute kidney injury if urine myoglobin exceeds renal threshold. Aggressive fluid resuscitation and urine alkalinization are preventive. **Clinical Pearl:** The "golden period" for compartment syndrome fasciotomy is within 6–8 hours; after 12 hours, irreversible damage is likely. This is more urgent than PE management in the immediate post-fracture phase.