Suspected surgical-site or deep infection — spreading erythema, purulence, fever, or a wound that opens — notify for culture/antibiotics; sepsis signs → transfer.

Deep-vein thrombosis / pulmonary embolism — unilateral calf swelling/pain, or sudden dyspnea/pleuritic pain/hypoxia — escalate/transfer (time-critical).

Neurovascular compromise — a cold, pale, pulseless, numb, or immobile operative limb, or pain out of proportion (compartment syndrome) — emergency evaluation/transfer.

Prosthetic dislocation or a new fracture (a fall, sudden deformity, severe pain, inability to bear weight) — immobilize and transfer.