Fracture blisters occur on skin overlying a

fractured bone A bone fracture (abbreviated FRX or Fx, Fx, or #) is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a '' ...

, and fractures complicated by the development of overlying blisters remain a clinical dilemma in orthopedics. Fracture blisters are tense

vesicles Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane * Synaptic vesicle ; In human embryology * Vesicle (embryology), bulge-like features o ...

or bullae that arise on markedly swollen

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

directly overlying a fracture. Fracture blisters pop up in trauma patients, but are relatively rare and only occur in 2.9% of patients with a fracture requiring hospitalization. A fracture blister typically occurs near fractures where the skin has little

subcutaneous tissue The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macr ...

between it and bone. These include

elbows The elbow is the region between the arm and the forearm that surrounds the elbow joint. The elbow includes prominent landmarks such as the olecranon, the cubital fossa (also called the chelidon, or the elbow pit), and the lateral and the media ...

knees In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

ankles The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular join ...

, and wrists. They tend to complicate fracture management because they interfere with splinting, casting, and incision planning for open reduction procedures. They can appear anytime within the first 6-8 hours following an injury, and most appear within the first 24-48 hours. At the location of the fracture, there is an increase in compartment pressure that is found around the area in limbs where blisters do not form and a fasciotomy is not performed, versus in those where the blisters are found. It is presumed that the formation of the blisters relieves some of the myofascial pressure.. It can be noted that there is a decreased number of tight junctions and activation of the paracellular pathway in the blistered skin, allowing for fluid passage into the blister. These blisters are thought to be caused by

shearing forces In solid mechanics, shearing forces are unaligned forces acting on one part of a body in a specific direction, and another part of the body in the opposite direction. When the forces are collinear (aligned with each other), they are called ...

applied at the time of injury. When the bones are broken and deform from their normal shape, the attached skin is then strained to a predictable degree which can be calculated using a formula that takes into account the angle of deformation and the start and end lengths of the area of skin being measured. The shearing and subsequent strain is a result of the difference in elasticity between the dermis and epidermis. There are two types, clear fluid and hemorrhagic, and the difference is found in the level of the shear. Clear fluid blisters separate layers within the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...

, and hemorrhagic blisters separate at the dermal-epidermal junction. It was found that a strain of 152% generated enough force to shear the skin layers and cause the formation of a hemorrhagic blister. Hemorrhagic blisters are more serious as they represent a complete stripping of epidermal cells. Clinically, the type of blister determines the healing time; clear blisters take about 12 days and hemorrhagic blisters heal in about 16 days. Risk factors that predispose a patient to formation of a blister include but are not limited to: anatomical sites with thin and tightly adhered overlying skin, peripheral vascular disease, collagen vascular disease, hypertension, smoking, alcoholism, diabetes mellitus, lymphatic obstruction, high energy injuries, and grade I and II open tibia fractures. Repair of the fracture prior to the formation of a blister is most ideal option. However, if that cannot be done, decision to pop the blisters in order to treat the fracture or wait for them to heal first usually hinges on the preferences of the orthopaedic surgeon as there is a lack of data on what treatment is ideal. Waiting delays care an average of 7 days, and longer for

tibial plateau Tibial may refer to: * Tibia bone * Tibial nerve * Anterior tibial artery * Posterior tibial artery * Anterior tibial vein * Posterior tibial vein The posterior tibial veins are veins of the leg in humans. They drain the posterior compartment of ...

and

calcaneal fracture A calcaneal fracture is a break of the calcaneus (heel bone). Symptoms may include pain, bruising, trouble walking, and deformity of the heel. It may be associated with breaks of the hip or back. It usually occurs when a person lands on their f ...

s. Operating immediately anecdotally increases wound infection rates.

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Skin conditions resulting from physical factors {{Cutaneous-condition-stub