Flashcards in Orthopaedics (Unit 5:Common fractures) Deck (105)
Which part of bone has a nerve supply?
Periosteum (the membrane which covers the outside of bones)
What are the 8 signs of a fracture?
Loss of function
How is swelling in a suspected fracture managed?
Raise above level of the heart
Why in a fracture does the disolouration change from dark to green then to yellow?
Dark = deoxygenated blood loss into soft tissues
As Hb in RBC is broken down and carried to liver by scavenger cells (colour changes to green then yellow)
What methods are used for investigating fractures?
When is tomography useful when investigating fractures?
When area is difficult to distinguish due to overlapping structures (e.g. axis bone)
How does radioisotope scanning work?
Radioactive substance attaches to phosphate molecules that are taken up actively taken up by bone.
The more metabolically active bone is the faster it takes up radioactive substance.
On x-ray unusual metabolic activity can be seen (i.e. fracture)
When is radioisotope scanning useful?
When there is clinical doubt
In not acute situations (2 weeks after injury)
Which bone in particular is radioisotope scanning useful for?
What should be commented on when describing a fracture?
Which bone & which side?
Open or closed?
Where on the bone is the break?
What shape is the fracture?
How many fragments
What is the position of the distal fragment?
Could it be pathological?
What are the 3 fracture shapes?
In what kind of injury do spiral fractures occur and how severe are they?
Twisting (low energy)
Associated with little soft tissue damage to blood supply is preserved and healing likely
What might cause oblique or transverse fractures?
Buckling or direct injury to bone (high energy)
What are the 3 ways to describe how many fragments are present in a fracture?
How is the distal fragment of a fracture described?
In terms of displacement, angulation and rotation
How is he angulation of the distal fragment of a fracture described?
As either anterior, posterior, varus or valgus
What is a pathological fracture?
When a fracture seems out of proportion to the violence of the injury
What does the immediate management of a fracture involve?
Pain relief splintage
What can be used as an alternative to splintage to relieve muscle spasm in the early management of a fracture?
Traction (particularly useful in femoral neck fractures)
Which fractures are most likely to be at risk of large blood loss?
Major long bones (femur, tibia)
How many units will a patient with a femoral fracture lose?
How many units will the average person with a tibia fracture lose?
How many units can an unstable pelvic fracture lose from the pelvic venous plexuses?
6 units or so
What is the treatment strategy for open fractures?
Clean them out and remove all dead tissue as soon as possible
Why are open fracture wounds sometimes left open?
If there is any doubt that closure can be achieved without any tension on the skin
If a patients wound is left open what extra treatment will they require?
Broad spectrum antibiotics
Why might a surgeon opt for a less than perfect result when managing a fracture?
The individual may be elderly or have poor bone quality and a less than perfect result might still allow them to do their daily activities (extensive treatment may have complications)
What process is used to return a bone to its normal position?
How is closed reduction performed?
Traction on the distal fragment and relocation of the distal part back onto the proximal fragment by manipulation
Name 4 methods of holding a fracture
What factors should be considered when casting a fracture?
Maintained at proper length
Immobilise joint above & below
How does a cast work?
Controls joint movement and position so pressure is exerted at 3 points
What are the disadvantages of casting?
Unable to examine
Unable to use x-ray
Muscle wasting (due to immobility)
Why do functional braces tend to be used after a few weeks?
They are highly dependent on a very accurate fit (gives time for pain and swelling to settle)
Which materials make ideal cast braces and why?
Glass fibre & polyurethane resin combinations (not so versatile but stronger and lighter)
What are the 2 stages of treating a fracture?
Reduction & Holding
Why are plaster splints highly unsuitable in high-energy fractures?
Assoc. with extensive soft-tissue damage so blood supply is severely damaged it is important to have an initial phase of soft tissue healing
Why is internal fixation hazardous to use in the management of fractures with extensive soft-tissue damage?
Increases infection risk
How does an external fixator work?
Fixed to the bones by pins and stabilises limb by external scaffold (provides stability and allows access to soft tissues)
Name a downside to external fixation?
Pin sites are an easy route for infection
When is internal fixation used?
When a high degree of accuracy is required or other methods fail
What are the 4 types of internal fixation?
Interfragmentary compression plus onlay device
What is apposition?
Once a fracture is realigned in only needs held in apposition for healing to procees
In what group is apposition particulary useful in and how is it achieved?
Children (using K wires)
What is interfragmentary compression and how is it achieved?
Holding 2 bone fragments firmly together (usually achieved by screws or sometimes tension band wires)
When is solely interfragmentary compression particularly useful?
In cancellous bone around joints
What are onlay devices used for in fracture management?
To buttress weak structures around joints
To fix long bones in the upper limb
What is the downside of olay devices?
Very rigid and inhibit natural bone union
Allow early movement but ultimately delay healing and full load bearing
Why are inlay devices good?
Achieve correct allignment
Don't disturb natural healing
Very strong (particularly useful in lower limb)
How can badly comminuted fractures be treated?
Cross screws inserted into bone using x-ray image intensifier
How does traction work?
Pull stimulates muscles to contract which surround the bone and hold the fracture in place
What are the 3 methods of traction?
Name an example of static traction
When is balanced traction used?
Where static traction is in danger of causing damage to a part of the body through pressure
How does dynamic traction work?
Joints are still permitted to move by means of pulleys
How long are weights applied for in traction?
Short periods of time (a few days)
How does traction diminish the need for pain-killing drugs in femoral fractures?
Changes muscle tone to relieve spasm
Which specific fractures is traction particularly useful in?
Femur fractures where splintage to include the hip joint is impractical
What is the main downside of traction?
The injured person must remain in bed making hospital stay prolonged and nursing care difficult
Over what time frame does callus form in bone healing?
Over what time frame does new bone start forming after a fracture?
What sort of movement help to stimulate bone healing?
Micromovement directed along the long axis of bone at right angles to the break
How should low energy fractures generally be treated?
Manipulation and casting (provided holding is possible)
How should low energy fractures be treated if holding is difficult?
If a fracture is displaced and involves a joint how should it be treated?
Why is internal fixation needed for fractures involving joints?
Needs to be very accurate and around joint cancellous bone tends to be fragmented and often with little soft tissue support
Why method of holding is particularly valuable in high velocity injuries?
Name 6 early complications that are primary (as a consequence of the injury)?
Soft tissue injury
Name 5 early complications that are secondary as a consequence of treatment?
Name 5 late complications of a fracture
What is the commonest cause of bone infection in the western world?
What dictates whether an infected fracture will heal?
Infection + stable = union
Infection + movement = non-union
How is an open infected fracture treated?
External fixation followed by surgical wound cleansing and later bone grafting
What precipiates pneumonitis after a fracture?
Breakdown of fats to fatty acids
Describe a typical patient who might get a fat embolism
Under 20 y/o
Fracture of long bone
When do symptoms of fat embolism present?
2-5 days from injury
What are the symptoms of fat embolism?
May have chest + neck rash
How is fat embolism managed?
Early diagnosis important
High % oxygen
Steroids given early (controversial)
What makes a patient prone to renal failure after a fracture?
Massive soft tissue injury
Trapped for prolonged periods
What is found in abundance in the kidneys of patient who die from renal failure after a fracture?
Where does compartment syndrome classically occur?
Forearm also calf
What structure surrounds groups of muscles?
What is the purpose of the fascial sheath?
Gives muscles shape
Anchors muscles to bone and surrounding soft tissue
Acts as muscle boundary creating compartments
Why does pressure increase in a compartment if a bone is broken?
Bleeding into adjacent compartments
What is compartment syndrome?
Increased pressure leads to reduced blood flow locally to muscles resulting in ischaemia
What are the symptoms of compartment syndrome?
Pain out of proportion to injury
Assoc. loss of function
Altered sensation over compartment
How does compartment syndrome affect the distal pulse?
Distal pulse normal
What is a useful diagnostic test for compartment syndrome?
Stretching muscles in compartment precipitates extreme pain
What is the first step of management of compartment syndrome?
Remove all dressing and split the plaster
If conservative measures fail how is compartment syndrome treated?
Surgical opening of fascia to decompress the compartment
How can compartment syndrome be prevented?
Early elevation of injured limb and ensure dressing are not too tight
What is fracture (plaster) disease?
Muscle wasting, stiffness and skin sores
What does early mobilisation discourage the development of? (5 things)
Renal stone formation
What causes renal stone formation if patient are immobile?
Calcium from the thinning bone
How long do upper limb fractures take to heal if left naturally?
6 weeks or so
How long do lower limb fracture take to heal fi left naturally?
12 weeks or sp
At which site in non-union most common?
Name 7 factors that might lead to non-union
Too little movement
Soft tissue interposition
Poor blood supply
Excessive traction or splinting bone too far apart
Intact adjacent bone (e.g. tib & fib)
How long is roughly defined as non-union in the upper limb?
How long roughly is defined as non-union in the lower limb?
What is delayed union?
Period between expected union and accepted non-union
How is non-union treated?
What does an autologous bone graft mean?
Taken from the bone of that individual (usually pelvis)
What is mal-union?
When a fracture has been allowed to heal in a position that precludes normal function