What is the preferred CXR view, PA or AP, for a suspected rib fracture in an adult or elderly patient with potential underlying conditions like osteoporosis?

Preferred CXR View for Suspected Rib Fracture

A standard posteroanterior (PA) chest radiograph should be the initial imaging test for suspected rib fractures, as recommended by the American College of Radiology. 1, 2, 3

Rationale for PA View Preference

The ACR Appropriateness Criteria explicitly state that "a standard posteroanterior (PA) chest radiograph should be the initial diagnostic test for detection of rib fractures" when combined with physical examination. 1 This recommendation prioritizes detection of life-threatening complications over fracture visualization itself, which directly impacts morbidity and mortality.

Why PA Over AP?

• PA views provide superior image quality with better anatomic definition and less magnification of mediastinal structures, making it easier to detect critical complications like pneumothorax, hemothorax, pulmonary contusion, and flail chest. 1

• The primary goal is detecting complications, not counting fractures - chest radiographs may miss up to 50% of rib fractures, but this does not alter patient management or outcomes in uncomplicated cases. 1, 3

• Complications detected on chest X-ray are more clinically significant than the fractures themselves, including pneumothorax, hemothorax, flail chest, and pulmonary contusion. 1

Clinical Context for Elderly and Osteoporotic Patients

• Age ≥65 years with multiple rib fractures carries significantly higher morbidity and mortality due to poor cardiopulmonary reserve, making early detection of complications even more critical in this population. 1, 2

• The presence of any rib fracture or parenchymal abnormality visible on plain radiography increases pulmonary morbidity risk 3.8-fold compared to fractures only detected by CT, emphasizing the prognostic value of standard chest X-ray findings. 1, 4

When PA View Is Not Feasible

• AP views are acceptable when patients cannot stand or sit upright (e.g., hemodynamically unstable, severe pain limiting positioning), though they provide inferior image quality. 4

• The key is obtaining the chest radiograph promptly to detect complications, regardless of whether PA or AP positioning is used. 1, 2

Common Pitfalls to Avoid

• Do not order dedicated rib series radiographs - they rarely add clinically significant information to the standard PA chest film and prolong turnaround time without changing management (only 0.23% of cases showed management change in one study). 1, 5

• Do not assume a normal chest X-ray excludes significant injury - while chest X-ray misses approximately 50% of rib fractures, fractures visible on radiography are associated with significantly increased pulmonary morbidity compared to CT-only detected fractures. 1, 4

• Do not rely on fracture detection alone - the chest radiograph's primary value is identifying complications (pneumothorax, hemothorax, pulmonary contusion) that directly impact treatment decisions and outcomes. 1

When to Escalate Beyond Standard Chest X-Ray

• Consider CT chest without contrast when multiple rib fractures are suspected despite negative radiographs in high-risk patients (elderly, long-term steroid use, osteoporosis), or when pathologic fracture is suspected. 2, 3

• Order contrast-enhanced CT if there is clinical suspicion of intrathoracic vascular injury, high-energy mechanism (>35 mph MVA, significant fall), hemodynamic instability, or widened mediastinum on chest X-ray. 2

• Six or more fractured ribs, especially in elderly patients, require ICU admission and may warrant CT imaging for precise anatomic definition to guide management decisions. 1, 2