Fracture blisters are thought to be caused by skin strain during fracture leading to cleavage at the dermo-epidermal junction. Increased interstitial pressure from post-traumatic edema and/or local tissue hypoxia (from venous stasis/thrombosis or injured vessels) are thought to be contributing factors. Risk factors include high-energy trauma and conditions that predispose to poor wound healing (peripheral vascular disease, collagen vascular disease, hypertension, smoking, alcoholism, diabetes mellitus, and lymphatic obstruction).
Some surgeons prefer to leave blisters intact and delay surgical stabilization until the blisters have resolved, pointing to evidence of increased complications (chronic ulcers, infection, and prolonged hospitalization) when surgical incisions are through blisters. However, no consensus currently exists on the optimal treatment strategy.
Familiarity with fracture blisters is required for proper assessment of pre-operative CT. They may also be occasionally seen on radiographs (image at LearningRadiology.com)