Management of Specific Fractures Flashcards
What type of tissue is bone?
A specialised form of connective tissue
What are some of the main functions of bone?
Support
Protection
Locomotion
Haematopoiesis- reservoir of stem cells for RBC formation
Lipid and mineral storage- particularly calcium
What are the 3 regions of bone and where are they found?
Epiphysis (next to the metaphysis at the top and bottom of the bone)
Metaphysis (next to the diaphysis)
Diaphysis (in the middle of the bone)
What type of bone is found in the epiphysis?
Cancellous (spongy) bone
What type of bone is found in the cortex?
Cortical (compact) bone
What layer surround the bone?
Periosteum
What is the periosteum and why is it important?
It is the outermost layer that surrounds the bone, it is important as its involved with the blood supply to cancellous bone
What is the role of flat bones?
To protect organs
What is the role of long bones?
Facilitate movement
What is the role of short bones?
Provide stability and movement by articulation
What is special about short bones?
They don’t have a diaphysis
Where are sesamoid bones found?
Embedded in tendon
What are the types of bone?
Flat Long Short Sesamoid Irregular
What are the 2 forms of bone?
Woven
Lamellar
What type of bone is formed first?
Woven
Describe woven bone
A temporary structure with random arrangements of collagen
Describe lamellar bone
Has a stronger and more regular structure than woven bone
What is the role of ECM in bone?
Provides biochemical and mechanical support
What does ECM in bone contain?
Collagen type 1 and 5 (90% type 1)
Mineral salts
What are the cellular components of bone?
Osteoblasts
Osteocytes
Osteoclasts
Osteoprogenitor stem cells
What is the role of osteoblasts in bone?
Synthesis of uncalcified ECM
What is the role of osteoclasts in bone?
Resorb bone
What is special about osteoclasts?
One of the few multinucleated cells in the body
What are bone stem cells called?
Osteoprogenitor cells
What are the 2 methods of bone formation?
Endochondral
Intramembranous
Compare the blood supply of bone to cartilage
Blood supply to bone is a lot richer
Describe endochondral ossification briefly
Bone development from hyaline cartilage
Describe intramembranous ossification briefly
Formation of bone directly onto fibrous tissue (bone development from fibrous membrane)
What state are bones constantly in?
A state of remodelling
What is the role of osteoclasts? Why are they needed?
Bone removal, this is needed as it increases calcium levels in the body
What is the role of osteoblasts?
Bone synthesis
How are osteoblasts activated?
They have receptors for PTH, prostaglandins, vitamin D and cytokines that activate the process of bone sythesis
What is Wolff’s law?
Bone adapts to forces placed upon it by remodelling and growing in response to these external stimuli
What is osteoporosis?
Reduced bone density
What is rickets/osteomalacia? What is the difference between them?
Low vitamin D
Rickets is what its called in children
Osteomalacia is what its called in adults
Define fracture
A discontinuity in the bone
What are the 4 ways fractures are desribed?
Orientation
Location
Displacement
Skin penetration
What are the possible orientations of fractures?
Transverse
Oblique
Spiral
Comminuted
What are the possible locations of fractures?
Epi/meta/diaphysis
ie position on the bone
What are the possible displacement categories of fractures?
Displaced
Undisplaced
What are the possible skin penetration categories of fractures?
Open
Closed
What does AO/OTA classification of fractures involve?
It considers the bone, where the fracture is, the type and the subgroup
Describe primary bone healing
Intramembranous healing that occurs via Haversian remodelling, which is when osteoblasts and osteoclasts co ordinate to heal via a cutter cone model
What gap size allows primary bone healing?
Little (<500 mm) or no gap
Describe secondary bone healing
Involves responses in periosteum and external soft tissue
A fast process resulting in callous formation made of fibrocartilage
The 4 steps are:
Haematoma formation
Soft callous formation
Hard callous formation
Remodelling
How is a haematoma formed in secondary bone healing?
Damaged blood vessels bleed
Neutrophils release cytokines signaling macrophage recruitment
How does a soft callous form in secondary bone healing?
Collagen and fibrocartilage bridge the fracture site and new blood vessels form
How does a hard callous form in secondary bone healing?
Osteoblasts, brought in by new blood vessels, mineralise the fibrocartilage to produce woven bone
What does remodelling involve in secondary bone healing?
Osteoclasts are removed and woven bone deposited then months to years after injury osteoclasts remove woven bone and osteoblasts laid down as ordered lamellar bone
What are the 3 main things fracture healing requires?
A very small fracture gap
Almost no movement if primary healing, some movement if secondary
Patients physiological state to be optimised
What is the difference in healing time for upper vs lower limb fractures?
Lower limb fractures take twice as long to heal as upper limb fractures
What is the difference in healing time for children vs adults?
Paediatric fractures heal twice as fast as adults
What is non union?
Failure of bone healing within an expected time frame
What are the 2 types of non union and how are they different?
Atrophic= healing completely stopped with no x ray changes, often physiological (smokers, diabetics, delayed presentation) Hypertrophic= too much movement causing callus healing
What is malunion?
Bone healing occurs but outside the normal parameters of alignment
What is the main difference between malunion and non union
In non union the bone doesnt heal and the 2 parts are not touching
In maunion the 2 parts touch but they are misalinged and they have healed
What are the 4 steps in management of a fracture?
Resuscitate
Reduce
Rest
Rehabilitation
What are the 2 main methods by which fractures can be managed?
Conservative
Surgical
What does conservative management of fractures involve?
First= rest, ice, elevation
Second=plaster/fibreglass cast or splint
Third= traction via skin or bone
What does surgical management of fractures involve?
MUA and K-wire- extra cortical
ORIF= open reduction internal fixation- extra cortical
IM nail= intermedullary nail intra cortical
External fixation- mono or bi planar (can’t close the defect at the time of the procedure)
When is MUA and K wire useful in fracture management?
Good in kids as they have very thick periosteum and later the wires can be pulled out
When is IM nail useful in fracture management?
Good for long fractures
When is external fixation useful in fracture management?
If you can’t close the defect at the time of the procedure
What most commonly causes shoulder dislocation?
Trauma
What is important to consider when there is a shoulder dislocation?
Check if there is axillary nerve damage as the brachial plexus near the shoulder
What are the 3 types of shoulder joint dislocation? Which is most common?
Anterior= most common, when the humeral head is not overlying the glenoid fossa Posterior= associated with seizures or shocks, lightbulb sign is seen Inferior= arm is held above the head and the humeral head is not articulating
What is the main method for treating shoulder dislocation?
Safest method is to use traction-counter traction +/- gentle internal rotation to disimpact humeral head
In shoulder dislocation what is Hill Sach’s defect?
Top of humeral head is hit on the glenoid as its dislocated
In shoulder dislocation what is Bankart lesion?
Damage to the labrum and/or glenoid, can be soft or bony
Typically who gets fracture of the proximal humerus?
Those with osteoporosis or the elderly
How is proximal humerus fracture managed?
Collar and cuff if the fracture is 2 parts
If more can do an ORIF
What physical action commonly causes a fracture of the proximal humerus?
Falling onto an outstretched hand
What are the 2 types of distal radius fracture?
Extra and intra articular
What are the 2 angulations possible in distal radius fractures?
Dorsal
Volar
Why is it important to look out for carpal fractures?
Missing them can result in loss of wrist function as blood supply may become compromised
What results in fractures when blood supply is lost?
Avascular necrosis
What is the commonest carpal bone fracture?
Fracture of the scaphoid bone
When should scaphoid bone fracture be considered?
In any distal radial injury but it commonly occurs because of a fall backwards onto the hand
How are fractures of the scaphoid managed?
If undisplaced conservative management in a cast is sufficient
If displaced ORIF is usually undertaken
How does dislocation of the lunate bone usually arise?
Progressive disruption to the ligament
