Orthopaedics Unit 5 Flashcards
what is the anatomical features of bone
has a very rich blood supply
periosteum is the membrane which covers the outside of the bone
- has a nerve supply
Mx of fracture priorities
early Mx
- minimise effects of blood loss
- reduce pain
Mx
- re-establish blood supply to the bone to allow it to heal
what questions need considered in the history of a fracture
what happened?
how did it happen?
where and when?
what was the injured person like before it happened?
who is the person?
what injuries are a person hit by a car likely to have
leg injuries from the bumper
pelvic and abdominal injuries from the bonnet
head injuries from the door pillar
what are the signs of a fracture
pain deformity tenderness swelling discolouration or bruising loss of function crepitus injury to other tissues
what influences the deformity of the bone after a fracture
position of the distal fragment of a fractured bone is determined by gravity
position of the proximal fragment is determined by the muscles
how can swelling be reduced in a fracture
elevate the part of the body injured
injured arm
- raised about level of the heart
injured leg
- lie patient down, with leg raised above chest level
what causes the colours of bruising
bruise at first is dark
- due to deoxygenated blood loss into soft tissue
bruise then becomes green/yellow
- as haemoglobin in the red blood cells is broken down and carried away to the liver
what 2 x-ray views are taken on a suspected fracture
one in sagittal plane
one in coronal plane
what is radioisotope scanning
when a very small quantity of a radioactive substance is injected into the blood of the injured person
how does radioisotope scanning work
- radioactive substance attaches to phosphate molecules which are actively taken up by bone
- then an x-ray is taken
- more metabolically active the bone is, the faster it takes up the radioactive substance
- sites of unusual metabolic activity (i.e. at the site of the fracture) can be clearly seen
when is radioisotope scanning used
useful in determining whether a bone is fractured or not
often used when a scaphoid [bone of the wrist] fracture is suspected
what questions should be answered when describing a fractured bone
which bone is broken and on which side?
is the fracture open or closed?
where on the bone is the fracture?
- intra-articular [in the joint]
- mid shaft
- proximal, middle or lower third?
what is the shape of the fracture?
- spiral
- oblique
- transverse
how many fragments?
- simple
- butterfly
- comminuted
what is the position of the distal fragment?
- describe distal fragment in relation to proximal one
could it be a pathological fracture?
how do spiral fractures occur
through twisting, low energy injuries
associated with little soft tissue damage = blood supply is preserved and healing should be no problem
when do you see oblique or transverse fractures
caused by buckling or direct injury to the bone
lots of energy involved
associated with soft tissue stripping and damage to the blood supply
require a lot more consideration for choice of Tx and usually take longer to heal
what are the 3 considerations when describing the position of the distal part of a fracture
displacement
- anterior
- posterior
- medial
- lateral
angulation
- anterior
- posterior
- varus
- valgus
rotation
- internal
- external
what are signs of a pathological fracture
fracture seems out of proportion to the violence of the injury
suggests bone is weak = result of osteoporosis or other diseases such as cancer
what are the headings of the immediate management of fractures
pain relief
managing blood loss
managing open fractures
what are the 2 methods of immediate pain relief
pain-killers
- i.e. morphine or pethidine injections
splintage
- hold fracture steady
- should encompass the joint above and below an injury
what is an alternative to splint age
traction
- also used in early Tx to relieve muscle spasm
when is traction particularly useful
fractures of the femoral neck
as splint age is impossible to apply
what type of fractures can lead to significant blood loss
major long bone fracture
i.e. femur
tibial # = 1 unit blood loss
femoral # = 2-3 units
major pelvic # = 6 units [major venous bleeding]
what is the Mx of all patients with major long bone injuries
cross matched for blood
wide bore cannula
- 2 lines if pelvic fracture
what is the Mx of open fractures and why is it important it happens quickly
clean them out and remove all dead tissue
- remove bits of clothing, dirt, wood, metal
prevent infection from bacteria
prevents potenital sepsis
what is the wound management of an open fracture
wounds are better left open if there is any doubt that closure cannot be achieved without any tension on the skin
wounds closed as a secondary procedure after a few days or left to heal spontaneously
Tx of open fractures
broad spectrum antibiotics
tetanus protection
what factors will determine what the long term, definitive management is of a fracture
the injured person
the injury
the surgery
what needs to be considered in the injured person in terms of management of the fracture
age of the patient, physical health and occupation
- older people tend to have a poor bone quality (osteoporosis) and co-existing medical problems [heart disease, diabetes]
how might the treatment of a wrist fracture be different in an elderly person and a young person
elderly
- fracture may be treated under local anaesthesia in the A&E
- not perfect result, but can go home and may have a satisfactory level of function
- surgery would require bed rest which might lead to complications like bedsores, UTI
young
- might be prepared to spend months undergoing Tx to ensure perfect result
- need it for work etc
what is essential to ensure when considering surgery
benefits outweigh the risks
what is the name of the process of returning the bone to its normal position
reduction
[and then holding the bone in place to allow healing]
what is close reduction
achieved by traction on the distal fragment
then relocation of that distal part back onto the proximal fragment by manipulation
need adequate analgesia
what does the manipulation of the fracture usually involve
reversing the direction of the deforming force
what is open reduction
site is open surgically and the fragments are relocated directly under vision
done if closed reduction doesn’t work
why does a bone need to be held in the desired position
bone needs to become strong enough to support itself (united) and then protected until it is strong enough to bear some load (consolidated)
how can a fracture be held in place
Casting
- surrounding the broken limb with a hard ‘coat’ which holds the fracture steady.
External fixation - an external ‘bar’ outside the body attached to pins sited in the broken bones.
Internal fixation - holding broken bones together using screws and plates inside the body.
Traction - pulling on a broken limb to align the bones.
what is casting
place limb in plaster of Paris cast until union
limb must be held in correct position and maintained at proper length [too long/short will delay union]
what must be covered in a plaster of paris cast
must immobilise the joints above and below the fracture site, as joint movement may result in distortion in one or more dimensions.
how does a cast work
acts as a splint
controls joint movement and position to control posture
plaster cast is folded so that pressure is exerted at 3 points
3 holding forces - mimics the direction of the reducing force sufficient to hold the reduction
disadvantages of casts
heavy
immobilise the joint
cannot examine the site
cannot x-ray
after cast is removed:
- muscle wasting
- limited mobility due to joint stiffness
what technique can be used to over come plaster cast
functional brace
- frees the joint
how does a functional brace work
accurate moulding and the provision of hinges, which permit motion in one direction, usually flexion and extension
- maintains 3D control of #
why is a functional brace normally fitted a few weeks after the injury
brace is reliant on a very accurate fit so need to wait for pain and swelling to reduce
what are disadvantages of the plaster of paris in regards to the material and what are alternatives
brittle messy difficult to apply well heavy can take 3 days to dry
glass fibre and polyurethane resin [however, not as versatile]
when are the alternative materials to plaster of paris used
used as secondary casts a week or two after the injury, once swelling has settled.
make ideal cast braces
why is external fixation (EF) used over internal fixation (IF) in some cases
High-energy # are associated with extensive soft-tissue damage
> blood supply is severely damaged
> need an initial phase of soft tissue healing
plaster splints are highly unsuitable because the wounds become inaccessible.
IF is hazardous because of ischaemia and wound contamination increases risk of an infection
how does EF work
device which is fixed to the bones by pins and which stabilises the limb by means of an external scaffold,
advantages of EF
provides stability of the bones
allows access to the soft tissues for dressings and secondary surgery i.e. skin grafting.
disadvantages of EF
pin sites are easy route for infection
what is internal fixation
holding of the fractured bone with devices such as screws, nails or plates.
what are the methods of IF
Apposition. Interfragmentary compression. Interfragmentary compression plus onlay device.
Inlay device.
what is apposition
once # is realigned - they are held in apposition [i.e. together in alignment]
hold position without producing immobility and so healing occurs by natural callus formation
what are methods of apposition
K or Kirschner wires
- semi-flexible wires
- useful in children
how are K wires removed
can be left standing proud of the bone
- can easily be pulled out once union is established and before consolidation.
what is Interfragmentary compression and when are they particularly valuable
holding two bone fragments firmly together
- achieved by screws [mainly] or tension band wires
achieve great accuracy
valuable in cancellous bone around joints
useful in long bones, particularly in upper limb [but may require extra support from an onlay device]
what is an onlay device
usually consists of a plate of metal
they are used to support weak structures around joints and to fix long bones in the upper limb
can an onlay device be used in the lower limb?
yes
however, generally not strong and certainly should not be used in the lower limb without interfragmentary compression
what are the disadvantages of an onlay system
rigid which inhibits natural bone union
delay healing and full load bearing due to eliminating micro-movement at the fracture site
what is an example of an inlay device
intra-medullary nails
advantages of an inlay device
- achieve correct alignment of the broken bones without unduly disturbing natural bone healing
- great strength make them ideal devices for Tx long bone #, particularly in the lower limb
disadvantages of an inlay device
- relatively inaccurate method of restoring anatomical position and so are not useful around joints
what is a potential Tx plan for a badly comminuted or rotated fracture
cross screws can be inserted in the bone using an X-ray image intensifier to show the bone and nail during surgery
why is the bone next to a fixation device weaker than normal bone
as it shares the load with the fixation device
bone at # gets thinner
adjacent unsupported bone is normal
thus a boundary is created between normal bone and weak, fixed bone leading to stresses at the abnormal/normal bone interface
[Wolff’s Law]
what is the current protocol for removal of implants [nails, screws]
possibility of link to bone tumours around implants but not proven
probably safer to remove implants in young people
- is risk of infection, damage to nerves and blood vessels during surgical removal
how does using traction as a holding device work
application of a relatively small weight to a limb, which exerts a pull along the axis of the broken limb
pull of at most 5 kilograms stimulates muscles to contract
this slight contraction [increase in muscle tone really] is sufficient to hold a broken bone in the position achieved at reduction
what are the 3 ways traction can be applied
static
dynamic
balanced
what is static traction and an example of it
where the pull is applied against another part of the body
In the Thomas splint, the pull is applied against the ring which presses against the pelvis
- used for femur #
only used for relatively short periods
when is balanced traction used
when static traction is in danger of causing damage to a part of the body through pressure
how does balanced traction work
the pull against the ring (and thus the pelvis) is balanced by a WEIGHT attached to the whole splint
takes pressure off the skin round the ring while maintain traction on the leg
when is dynamic traction used
when joints are still permitted to move but, by means of pulleys, the pull is still maintained along the line of the broken bone
how does dynamic traction work
weights provide the pull and the counter force is achieved by tilting the bed
weights are not large and are only applied for a few days
useful when traction is being used to relieve pain, like following a femoral neck #
advantage of short term dynamic traction
results in a change in muscle tone, relieving muscle spasm and reduces need for pain-killers
what is required for long term traction
larger weights
- a pin inserted through the bone is preferable and in the long run easier to manage.
Pins can loosen, and/or become infected.
Regular nursing care of pin tracts is essential to keep them clean and dry.
when is dynamic traction useful
useful where other external Tx fail
1 - femur #’s where splint age to include the hip is impractical
2 - extensive soft tissue damage as an alternative to EF
what is the main disadv of dynamic traction
injured person must remain in bed, making hospital stay prolonged and nursing care difficult.
what is the time line for bone healing
first 2 weeks = swelling
2-6 weeks = callus forming
6-12 weeks = bone forming
6-12 months = hard callus
1-2 years = remodelling has taken place and the bone returns to normal
what is need to stimulate bone healing
micro-movement directed along the long axis of the bone at right angles to the break
[heal least efficiently if subjected to shearing forces or large movements.]
[bones will heal if there is no movement, they do so very slowly and by a different process]
what is bone healing highly dependant on
a good blood supply
why is rigid fixation not great for bone healing
does not allow micro movements - bone will heal but at a slower rate
most marked in long bones and less problematical in cancellous bone, which tends to heal fairly quickly
general overview of management of low energy injuries #
manipulation and casting provided that holding is possible
if holding is difficult, may use traction, functional brace or IF
IF justified if it leads to early mobilisation of the injured person
general overview of management of # involving joints
generally, IF if # is displaced
Open reduction is mostly needed to get the degree of accuracy required
holding requires accurate reconstruction of the fragments, usually with screws to aid stability or k-wires
[cancellous bone tends to be fragmented which can make holding difficult]
general overview of management of high velocity injuries
require special attention because of the damage to the blood supply
EF useful if soft tissue damage
what type of cancers is bone cancer commonly secondary too
lung, breast, thyroid and kidney
why are internal fixation techniques used for fractures of the elderly
permit early mobilisation and thus a return to normal function as soon as possible.
what are the early complications of a fracture
Blood loss. Infection. Fat embolism. Renal failure. Soft-tissue injury. Compartment syndrome
what are the late complications of a fracture
non-union delayed union mal-union growth arrest arthritis
what are early complications of the Tx of a fracture
Plaster disease. Renal stones. Immobility. Infection. Compartment syndrome.
what are late complications of the Tx of a fracture
mal-union
infection
what is the commonest cause of bone infection in the western world
surgery
why would a bone infection sometimes not be treated? what could be done?
Provided a fracture is held stable then it will unite despite infection.
[If there is infection AND movement then non- union is most likely]
Tx
- drain any pus collection
- give antibiotics until union has occurred
what is the management when an open # that is unstable OR for an unstable but FIXED # becomes infected
stabilisation by EF followed by surgical wound cleansing
later bone grafting will be required.
who is a fat embolism normally seen in and how does it present
after the fracture of a long bone in men < 20 years old
Sx commence within 2-5 days after injury
Sx
- tachypnoea [shallow rapid breathing]
- mild confusion
- may have rash on chest and neck
Tx of fat embolism
high percentage oxygen and chest physiotherapy
[late diagnosis will lead to ventilation being required, high mortality rate]
how is renal failure caused after a #
people trapped for prolonged periods, become ischaemic
skeletal muscle begins to break down, high levels of myoglobin released
toxic to the kidneys»_space;> causes renal failure
what is compartment syndrome
All muscles are surrounded by tough fibrous tissue called fascia.
Groups of muscles are surrounded by a thicker layer of fibrous tissue (the fascial sheath).
Fascial sheath creates compartments containing muscle, blood vessels and nerves
Bone #»_space;> bleeding into compartment and swelling from inflammatory reaction
Leads to increase in pressure within the compartment
Leads to reduced blood flow locally to the muscles»_space; ischaemia
where does compartment syndrome classically happen
in the forearm
[also in the calf]
what is an example of a non fracture related compartment syndrome
shin splints
Sx of compartment syndrome
Pain - out of proportion to injury
Pressure
Paralysis - loss of function
Pulse distal to compartment is normal
Pallor/pale
Paresthesia (numbness)
what is the test for compartment syndrome
passive stretching from the examiner causes severe pain
Tx of compartment syndrome
fasciotomy
what are the features of fracture disease
Muscle wasting, stiffness and skin sores
what are side effects of immobility
osteoporosis
renal stones - caused by calcium from thinning bones
stiffness
muscle wasting
skin sores
what is the normal healing period for upper and lower limb fractures
upper - 6 weeks
lower - 12 weeks
[although growing children do heal faster than adults]
what bone is non-union most common in
tibia
- due to its rather exposed site under the skin with little surrounding muscles and soft tissue
what are the factors thought to cause non-union
excess movement little movement [rigid IF] poor blood supply soft tissue between bone ends infection excessive traction
when is non-union said to occur
when injured person and/or the surgeon feels that healing has taken too long
rule of thumb:
lower limb - 20 weeks
upper limb - 10 weeks
what is delayed union
period between expected union and accepted non-union when the decision to do something is contemplated.
Tx for non union
relies on underlying cause and then stimulating union
1 - stabilise fracture
2 - add an autologous bone graft [taken from another bone, usually the pelvis, of the same individual]
3 - graft placed next to the # site
what is mal union
fracture has been allowed to heal in a position that inhibits normal function
due to failure of Tx method
how is mal union Tx
ORIF
what is growth arrest
when there has been a # within the epiphyseal growth plate
may cause arrest at point of breach
resulting in deformity
when is secondary OA at a fracture site likely
1 - if fracture goes across a joint and disturbs the surfaces so joint is no longer congruent [i.e. 2 surfaces are no longer parallel]
2 - an angulated fracture as it puts uneven forces on a joint
[good Mx should minimise risk of OA but will not totally exclude]
