Marcie, 85-year-old woman was riding her bicycle when she hit a deep pothole in the bike lane. She lost control and crashed to the ground. The patient is diagnosed with a femoral head fracture. Which complication is most concerning?

Brief Introduction: Avascular necrosis (AVN), or osteonecrosis, involves the death of bone tissue due to an interrupted blood supply. The femoral head is particularly vulnerable because its primary circulation, the medial circumflex femoral artery, is frequently disrupted during intracapsular fractures, leading to bone collapse and permanent joint destruction if not addressed surgically. Rationale: A. The femoral head has a precarious blood supply that is often compromised in displaced fractures. In an active 85-year-old, the risk of ischemic necrosis is the highest priority because it leads to femoral head collapse, requiring total hip arthroplasty to restore mobility. B. Kidney stones are a metabolic complication unrelated to the acute mechanical trauma of a hip fracture. Immobility can eventually lead to urinary stasis and stone formation, but it is not a concerning complication in the immediate post-injury phase compared to the risk of losing bone viability. C. Although muscle strain likely occurred during the fall, it is a minor injury that does not threaten the patient's long-term independence. In the presence of a confirmed cortical break, focusing on soft tissue strain ignores the catastrophic potential of the underlying skeletal and vascular damage sustained. D. Deep tissue bruising and ecchymosis are expected clinical findings following high-impact blunt trauma. Bruising indicates vascular disruption in the soft tissues, but it is a self-limiting condition that does not carry the significant morbidity or surgical implications associated with the death of the femoral bone.