Posterior wall fractures of the acetabulum are the most common acetabular fracture pattern. Stable, congruous hips are amenable to nonoperative management, whereas any instability in the hip is an indication for operative management of the posterior wall fracture. Stability cannot adequately be predicted by static imaging alone. Therefore, the dynamic stress examination under anesthesia remains the gold standard in determining hip stability to guide treatment. This case-based video demonstrates a systematic technique for performing an examination under anesthesia and explains how to interpret the fluoroscopic imaging to differentiate stable and unstable hips.