Management of specific fractures Flashcards
what are the functions of bone?
support
protection
locomotion
hematopoiesis
lipid and mineral reservoir (particularly calcium)
what are the types of bones?
flat bone
long bones
irregular bones
short bones
sesamoid bones
what are the functions of flat bones and examples
protect internal organs
skull, thoracic cage, sternum, scapula
what are the functions of long bones and examples?
support and facilitate movement
humerus, radius, ulna, metacarpals
what is the function of irregular bones?
vary in shape and structure
e,g vertebrae, sacrum, pelvis, pubic, ilium or ischium
what are the features of short bones?
no diaphysis
as wide as they are long
provide stability and some movement
e.g carpals, tarsals
what are the functions of sesamoid bones?
embedded within tendons
potentially to protect tendons from stress or wear
e.g patella
what is the overall anatomy of bone?
what do bones have on the outside layer?
periosteum- provides blood and nutrition
what are the overall types of bones that can be formed?
woven (primary) bone
lamellar (secondary) bone
what is woven bone?
first type of bone to be formed- in embryonic development and fracture healing
consists of osteoid, randomly arranged collagen fibres
temporary structure replaced by mature lamellar bone
what is lamellar bone?
bone of adult skelton
highly organized sheets of mineralized osteoid, making it much stronger than woven bone
two types (compact and spongy)
what is the extracellular matrix bone function?
biomechanical and structural support
what does the extracellular matrix of bone contain?
collagen- type 1 (90%) abd type V
mineral salts- calcium hydroxyapatite
what is ECM initially called?
osteon
how does calcification occur?
mineral salts interpose between collagen fibres
what do osteoblasts do?
synthesise undifferentiated ECM
what are osteocytes?
osteoblasts entuned in bone
what are osteoclasts?
from monocytes
reabsorb bone
multinucleated cells
release H+ ions and lysosomal enzymes
what are osteoprogenitor cells?
undifferentiated stem cells
what is the difference between blood supply to bone and cartilage?
bone has a better blood supply
nutrient arteries supplying diaphysis and meta/epiphyseal vessels
how can bone grow?
endochondral
intramembranous
what is endochondral growth?
formation of bone onto a temporary cartilage scaffold
e.g hyaline cartilage replaced by osteoblasts secreting osteid in femur
what is intramembranous growth?
formation of bone directly onto fibrous connective tissue
e.g. temporal bone or scapula
provides width to bones
what is bone removal undertaken by?
osteoclasts
why is osteoclast action necessary?
essential bone removal for body’s metabolism as removal of bone increases calcium in blood
what is bone production done by?
osteoblasts
how do osteoblasts synthesis new bone?
have receptors from PTH, prostaglandins, vit D and cytokine
activate and allow them to synthesise bone matrix
what does the coordinated action of osteoblasts and osteoclasts do?
take place as cutting cones that essentially drill through old bone
what do osteoblasts and osteocytes do in coordination?
lay down concentric lamellae and form osteons
what occurs in osteoporosis?
decrease in bone density, reducing structural integrity
osteoclast > osteoblast activity
increased risk fragility fracture
3 types: postmenopausal, senile, seondary
what happens in rickets/osteomalacia?
vit D or calcium deficiency in children (rickets) or adults (osteomalacia)
osteoid mineralizes poorly and remains pliable
in rickets= epiphyseal growth plates can become distorted under weight of the body
in osteomalacia= increased risk of fracture
what is osteogenesis imperfecta?
abnormal collagen synthesis
increased fragility of bones, bone deformities and blue sclera
rare, genetic autosomal dominant inheritence
can be mistaken as NAD in children
what is a fracture?
discontinuity of bone
what can the orientation of fracture be?
transverse
oblique
spiral
comminuted
what are the locations that a fracture can be on the bone?
what can the displacement be on a fracture?
displaced
undisplaced
what can the skin penetration be on a fracture?
open or closed
what are the types of fracture healing?
primary/ direct
secondary/ indirect
what is the process of primary bone healing?
cutter cone concept- line bone remodeling
intramembranous healing, occurs via Haversian remodeling
little or not gap (no movement)
slow process
what is the process of secondary bone healing?
endochondral healing, involved responses in the periosteum and external soft tissues
fast process resulting in callus formation (fibrocartilage)
- Haematoma formation
- soft callus formation
- hard callus formaiton
- remodelling
what happens in haematoma formation in bone healing?
damaged blood vessels bleed forming a hematoma
neutrophils release cytokines signalling macrophage recruitment
what happens during soft callus formation?
collagen and fibrocartilage bridge the fracture site and new blood vessels form
what happens during hard callus formation?
osteoblasts brought in by new blood vessels mineralise the fibrocartilage to produce woven bone
what happens during remodelling in bone healing
months to years after injury
osteoclasts remove woven bone and osteoblasts laid down as ordered lamellar bone
what are the pre-requisites for bone healing?
- minimal fracture gap
- no movement if direct (primary) bone healing or some movement if indirect bone dealing
- patient physiological state- nutrients, growth factors, age, diabetic, smoker
what is the time frame for bone healing?
about 6 months
lower limb fractures twice as long as upper to heal
paediatric heal twice as quickly
what law is bone remodelling determined by?
Wolff’s law
bone adapts to forces placed upon it by remodelling and growing in response to these external stimuli
what is done if the femur heals bent in a child?
axial loading should be direct
with remodeling occurring through axial loading
periosteum on the concave side will make more bone while on the convex side will be reabsorbed
this causes it to straighten
what are the fracture healing complications?
non union and malunion
what is non-union?
failure of bone healing within an expected time frame
what are the types of non-union healing?
atrophic- healing completely stopped with no XR changes, often physiological
oligotrophic
hypertrophic (horse hoof and elephant foot)- too much movement, causing callus healing
what is malunion bone healing?
bone healing occurs but outside of normal parameters of alignment
what are the key principles of fracture management
- resuscitate- save patient first
- reduce- bring bones back together in acceptable alignment
- rest- hold fracture in position
- rehabilitate- bring back function and avoid stiffness
what are the conservative fracture management procedures?
rest, ice, elevate
plaster fibreglass cast/splint
traction-skin/bone
what are the surgical fracture management?
external fixation- monobiplanar, multiplanar ring
internal fixation- ORIF, IM nail, MUA+ K wire
arthroplasty- hemiarthroplasty, total joint replacement
what is the presentation of a shoulder dislocation?
variable history but often direct trauma
pain
restricted movement
loss of normal shoulder contour
what assessment needs to be done in shoulder dislocation?
assess neurovascular status- Auxillary nerve
what investigations should be done in shoulder dislocation?
X-ray prior to any manipulation- identify fracture e.g humeral neck, greater tuberosity avulsion or glenoid
scapular- Y view/modified axillary in addition to AP
what are the types of shoulder dislocation?
anterior- commonest, bimodal distribution, humeral head not overlying glenoid
posterior - rare, associated with seizures/shocks, lightbulb sign on XR
inferior- rare, arm held abducted above head, humeral head not articulating correctly
what is the management for shoulder dislocation?
vigorous manipulation or twisting manipulation should be avoided to avoid fractures
safest method is traction-counter traction +/- gentle internal rotation to disimpact humeral head
ensure adequate patient relaxation
stimson method if alone
same environment esp if elderly- e.g resus
what are the complications of a shoulder dislocation?
neurovascular
damage to labrum and or glenoid
damage to humeral head
recurrent dislocations
when does a neurovascular complcation of shoulder disolcation present?
at time of presentation due to trauma sustained e.g axillary nerve
iatrogenic as result of reduction maneuver
delated onset due to evolving haematoma post injury/ manipulation
what is the sign of damage to the labrum and/or glenoid?
bankart lesion- soft or bony
what lesion is created from damage to humeral head?
Hi–Sachs lesion
what is the trend with recurrent dislocations and age?
the younger the patient the greater the risk of repeat dislocations
what is the typical presentation for proximal humerus fracture?
fall onto an outstretched hand
typically in elderly or those with osteoporosis
what are the investigations for proximal humerus fracture?
plain XR
CT if concern over articular involvement or high degrees of comminution
what are the classifications for proximal humerus fracture?
2 part- surgical neck fractures and greater tuberosity fracture
3 part fracture
4 part fracture
what is the management for proximal humerus fracture?
collar and cuff
ORIF- plate and screws
arthroplasty- humeral head fracture with large displacement (high risk non-union)
reverse arthroplasty- unrepairable rotator cuff, previous unsuccessful shoulder replacement, complex fracture/ chronic shoulder dislocation
what is the presentation of distal radius fracture?
very common
bimodal distribution
often present with the mechanism of falling on the affected area
swelling and visible deformity
dorsal displacement due to fall on outstretched hand common
what are the classification types for distal radius fractures?
- extra articular
- dorsal angulation- colles fracture
- volar angulation- smith fracture
- intra-articular
- dorsal angulation- dorsal barton
- volar angulation- volar/reverse barton
