fracture Flashcards
fracture
A fracture is a distruption or break in the continuity of the structure of bone.
Trauma accounts for the majority of fractures although some are secondary to a disease such as cancer or osteoporosis. These fractures are referred to as pathological fractures.
Classification
Type of fracture
Communication ( open/compund #) or non-communication (closed/simple #) with the external environment
Location of the fracture on the bone involved
Stable (intact and aligned) or unstable (displaced, a site or poor fixation)
Clinical Manifestations
Patients history
Fall
MVA
Trauma
Oedema & swelling
Disruption & penetration of bone through skin or soft tissues
Bleeding into surrounding tissues
Pain & tenderness
Muscle spasm as a result of involuntary reflex action of muscle Direct tissue trauma Increased pressure of nerves Movement of fracture parts Muscle spasm
Irritation of tissues
Protective response to injury & fracture
Deformity
Abnormal position of extremity/part
Action of muscles pulling fragment into abnormal position
Loss of normal bony contour
Ecchymosis/contusion
Discolouration of skin as a result of extravasation of blood in subcutaneous tissue
Loss of function
Disruption of bone or joint preventing functional use of limb or part
Crepitation
Grating or crunching together of bony fragments
Produces palpable or audible crunching or popping sensation
A Fracture haematoma
Bleeding creates a haematoma which surrounds the ends of the fragments.
The haematoma is blood that changes from liquid to semisolid clot.
This occurs in the initial 72 hours after injury
Granulation tissue
Active phagocytosis absorbs the products of local necrosis.
The haematoma converts to granulation tissue.
Granulation tissue consists of new blood vessels, fibroblasts and osteoblasts.
This provides the basis for new bone substance called osteoid.
Occurs day 3 - 14 post injury.
Callus formation
Minerals calcium, phosphorus & magnesium and new bone matrix are deposited in the osteoid.
An unorganised network of bone is formed that is woven about the fracture parts.
Callus is prmarily composed of cartilage, osteoblasts, calcium & phosphorus.
Usually appears by the end of the 2nd week after injury.
Evidence of callus formation can be seen on X-ray
Ossification
Ossification of the callus occurs from 3 weeks - 6 months after the fracture and continues until the fracture is healed.
Callus ossification is sufficient to prevent movement at the fracture site when bones are gently stressed.
The fracture is still evident on X-ray
Consolidation
Callus continues to develop the distance between bone fragments diminishes and eventually closes
Remodelling
Excess bone tissue is reabsorbed in the final stage of bone healing and union is complete
Gradual return of bone to pre-injury structure and shape occurs
Bone remodels in response to physical loading stress (weight bearing and exercise)
New bone is deposited in sites subjected to stress and reabsorbed at areas where there is little stress
Radiological union
X-ray evidence of complete bone union
Can be up to 1 year after injury
Complications of Fracture Healing
Problem
Delayed Union
Fracture healing progresses more slowly than expected. Healing eventually occurs.
Non- Union
Fracture fails to heal properly despite treatment. Results in fibrous union or pseudoarthrosis.
Malunion
Fracture heals in expected time but in unsatisfactory position. May result in deformity or dysfunction
Angulation
Fracture heals in abnormal position in relation to midline of structure (type of malunion)
Pseudoarthrosis
Type of non-union occurring at fracture site in which a false joint is formed on the shaft of long bones. Fracture site that failed to fuse. Each bone end is covered with fibrous scar tissue
Refracture
New fracture occurs at original fracture site
Myositis Ossificans
Deposition of calcium in muscle tissue at the site of significant blunt muscle trauma or repeated muscle injury
Complications of Fractures
Infection
Open fractures and soft tissue injury have a high incidence of infection
Devitalised and contaminated tissue is an ideal medium for many common pathogens
Compartment Syndrome
Muscles are contained within non-elastic fascia called compartments
Elevated intracompartmental pressure within a confined myofascial compartment comprises the neurovascular function of tissues within that space.
Compartment syndrome causes capillary perfusion to be reduced below the level necessary for tissue viability.
Two types: (1) decreased compartment size resulting from restrictive dressings, splints, casts, excessive traction or premature closure of fascia or (2) increased compartment content related to bleeding, oedema, chemical response to snakebite or IV filtration
Oedema is a response to soft tissue injury and may elevate the compartment pressure.
If the pressure is sufficient it can obstruct circulation and cause venous occlusion which increases oedema
Eventually arterial flow is compromised resulting in ischaemia to the extremity
As ischaemia continues, muscles and nerve cells are destroyed
Contracture, disability and loss of funtion can occurs
Clinical Manifestations of Compartment Syndrome
The seven P’s: Patients may present with one or all of the following
Paraesthesia: numbness & tingling
Pain: not relieved by analgesia
Pressure: increases in the compartment
Pallor: loss of normal colour of the extremity
Paralysis: loss of function
Pulselessness: diminished or absent peripheral pulse
Polar: the affected extremity is cool to touch
Venous Thrombosis
Veins of the lower extremities and pelvis are highly susceptible to thrombus formation after a fracture.
Venous stasis can be caused by incorrectly applied casts or traction, local pressure on a vein or immobility.
Venous stasis is aggravated by inactivity of the muscles that normally assist in the pumping action of venous blood return
Fat embolism
Presence of systemic fat globules that are distributed into tissues and organs after a traumatic skeletal injury.
Fractures more common in causing fat embolism include long bones, ribs, tibia & pelvis.
Also know to occur after joint replacement, spinal fusion, liposuction, crush injuries & bone marrow transplant.
Mechanical theory suggests that fat is released from the marrow of injured bone driven out by an increase in pressure and enters the circulation where it travels and lodges.
Biochemical theory suggests that catecholamines released at the time of trauma mobilise free fatty acids from the adipose tissue causing chlyomicrons to form large fat globules that eventually lodges.
Tissues most affected are the lungs, brain, heart, kidneys, skin
