Management of Specific Fractures Flashcards

1
Q

What is bone?

A

Connective tissue that has a unique histological composition

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2
Q

What are the 5 functions of bone?

A
  1. Support = framework and shape of the body
  2. Protection = surrounds major internal organs and vasculature
  3. Locomotion = joints to allow flexibility and attachment site of muscles
  4. Haematopoesis = reservoir of stem cells forming blood cells
  5. Lipid and mineral storage = adipose tissue stored within bone marrow and calcium within hydroxyapatite crystals
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3
Q

What are 5 different types of bone?

A
  1. Flat bones - protect internal organs e.g. skull, thoracic cage, sternum, scapula
  2. Long bones - support and facilitate movement e.g. humerus, radius, ulna, metacarpals
  3. Irregular bones - vary in shape and structure e.g. vertebrae, sacrum, pelvis – pubic, ilium or ischium
  4. Short bones - no diaphysis, as wide as they are long, provide stability and some movemente.g. carpals, tarsals,
  5. Sesamoid bones - embedded within tendons, allows for dynamic action, also protects tendon from excessive stress / wear e.g. patella
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4
Q

What is the anatomy of the long bone?

A

Epiphysis = end
Metaphysis
Diaphysis = main body of the bone

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5
Q

What is found in the cross section of bone?

A

Epiphysis = cancellous (spongey) bone

In the cortex (i.e. border) = compact / cortical bone

Epiphyseal line = growth plate

Periosteum and nutrient arteries = provided blood supply and nutrients to bone

Medullary cavity

Yellow bone marrow surrounded by endosteum

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6
Q

What are the 2 bone ultrastructures of bone?

A
  1. Primary = 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
  2. Secondary = lamellar bone:
    - Bone of the adult skeleton
    - Highly organised sheets of mineralised osteoid, making it much stronger than woven bone
    - Can be divided into compact and cancellous
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7
Q

What is the ultrastructure of compact (cortical) VS spongy (cancellous) bone?

A

Compact (cortical) bone =

  • Found in the diaphysis, forms the outer part of bone
  • Organised in concentric circles around a vertical Haversian canal
  • Haversian canal are connected by Volkmann’s canals which contain small vessels that also supply periosteum |-|_| (so the vertical lines are haversian canals, the horizontal lines are volkmann’s canals)
  • Osteocytes located between lamellae, within small cavities called lacunae - these are interconnected by a series of tunnels called canaliculi.
  • Entire structure is known as an osteon, the functional unit of bone

Spongy (cancellous) bone =

  • Found in the epiphysis, irregular crosslinking of trabeculae to form porous yet strong bone resistant against multidirectional lines of force
  • Large spaces between trabeculae giving it a honeycombed appearance, contains red bone marrow
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8
Q

What are the biochemical and structural support components that make up the extracellular matrix of bone?

A

Mineral salts - calcium hydroxyapatite (70% of bone)

Collagen - Type I (90%) and Type V

Calcification of bone occurs when mineral salts interpose between collagen fibres, ECM is called osteoid before this

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9
Q

What are the cellular components of bone?

A

Osteobasts - synthesiseuncalcified ECM (osteoid)

Osteocytes - as osteoid mineralizes, osteoblasts are entombed between lamellae, becoming osteocytes; regulate bone mass by monitoring mineral composition and protein content

Osterclasts - they are multinucleate cells derived from monocytes and resorb bone, they release H+ ions and lysosomal enzymes

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10
Q

How does bone ossify (i.e. grow)?

A

2 methods:

  1. Endochondral =
    Formation of bone onto a temporary cartilage scaffold e.g. hyaline cartilage replaced by osteoblasts secreting osteoid in femur = provides length
  2. Intramembranous =
    Formation of bone directly onto fibrous connective tissue e.g. temporal bone or scapula = provides width to bone
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11
Q

How does the blood supply between bone and cartilage differ?

A

Bone has very good blood supply compared to cartilage

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12
Q

Once bone is formed, what happens?

A

Constant state of turnover - remodelling

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13
Q

How does bone remodelling work?

A

Bone removal undertaken by osteoclasts = essential for body’s metabolism as removal of bone increases calcium in blood

Bone production undertaken by osteoblasts =
osteoblasts have receptors from PTH, prostaglandins, vitamin D and cytokines that activate and allow them to synthesisebone matrix

Synergistic / co-ordinated action between 2 = allow for bone remodelling

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14
Q

How are osteoblasts activated?

A

PTH

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15
Q

Where do osteocytes form from?

A

From osteoblasts, which lay down concentric lamellae and form osteons

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16
Q

Why is bone remodellling relevant cliincally?

A

Nutrient deficiencies = bone disorders

Osteoporosis =

  • Decrease in bone density, reducing structural integrity
  • Osteoclast > osteoblast activity
  • Increased risk of fragility fracture
  • Three types: postmenopausal, senile, secondary

Rickets / Osteomalacia =

  • Vitamin 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 - bendy bones
  • Osteomalacia = increased risk of fracture

Osteogenesis imperfecta =

  • Abnormal collagen synthesis
  • Increased fragility of bones, bone defomirtiesand blue sclera
  • Rare, genetic autosomal dominanyinheritance
  • Can be mistaken as NAD in children diagnosis important medicolegally
17
Q

What is a fracture?

A

Discontinuity of bone

18
Q

What are the 4 key points in describing a fracture clinically?

A

Orientation - of fracture e.g. transverse, oblique, spiral, comminuted

Location - position on bone e.g. proximal third, middle third or distal third

Displacement - can either be displaced or undisplaced

Skin penetration - can either be an open or closed fracture

19
Q

Why do we classify fractures using those 4 points?

A

Improves communication

Assists with prognosis and treatment

20
Q

What are the 3 different classification systems?

A

Descriptive classification e.g. Garden, Schatzker, Neer, Wber

Associated soft tissue injury e.g. Tscherne(closed) or Gustilo-Anderson (open)

Universal classification e.g. OTA classification

21
Q

What is the AO/OTA classification system?

A

Number for bone
Number for where (proximal/distal)
Number for subgroup of type of fracture

22
Q

What are the 2 types of fracture healing?

A

Primary (or direct) bone healing

Secondary (or indirect) bone healing

23
Q

What is primary (or direct) bone healing?

A

Intramembranous healing, occurs via Haversian remodeling

Little (<500mm) or no gap

Slow process

Cutter cone concept – like bone remodelling

24
Q

What is secondary (or indirect) bone healing?

What are the 4 steps of secondary bone healing?

A
  • Endochondral healing, involves responses in the periosteum and external soft tissues
  • Fast process resulting in callus formation (fibrocartilage)
  1. Haematoma formation =
    Damaged blood vessels bleed forming a haematoma, neutrophils release cytokines signaling macrophage recruitment
  2. Soft callous formation =
    Collagen and fibrocartilage bridge the fracture site and new blood vessels form
  3. Hard callus formation =
    Osteoblasts, brought in by new blood vessels, mineralise the fibrocartilage to produce woven bone
  4. Remodelling =
    Months to years after injury osteoclasts remove woven bone and osteoblasts laid down as ordered lamellar bone
25
What are the ideal conditions for fracture healing? How long does fracture healing take?
Minimal fracture gap No movement if direct bone healing or some movement if indirect bone healing Patient physiological state - nutrients, growth factors, age, diabetic, smoker
26
How do these conditions feed into clinical management of fracture healing?
Pre-defined time-frame expectations e.g. most fractures heal ~6months Pump up those with nutrients before procedures Increased risks = diabetes, smoking Children (pardiatric patients) heal 2x quicker than adults - follow-ups planned accordingly (like 1 week later, to ensure you target the window of opportunity to align a future displacement) Lower limb fractures taking twice as long as upper limb fractures to heal
27
What is Wolff's law?
Bone, i.e. outside their fracture state, remodels based on external stimuli (forces placed upon the bone) So in a child, the femur will heal bent due to body weight - remodelling occurs due to axial loading Periosteum on the concave side will make more bone while on the convex side, bone will be resorbed
28
What are some fracture healing complications? | Non-union VS Malunion
Non-union = failure of bone to heal within an expected time frame: - May be due to atrophy (usually result of physiological problems e.g. smoking, diabetes, malnutrition) = healing completely stopped with no Xray changes OR - Hypertrophic = too much movement causing callus healing = too much callus formed (on the sides of the bone called elephant foot) = does not unite to form a hard callus Malunion = bone healing occurs but outside of the normal parameters of alignment - so bone healing is taking place in the wrong place Names of different fracture healing complications include: malunion, atrophic non-union, hypertrophic non-union (horse hoof), hypertropic non-union (elephant foot), pseudoarthrosis
29
What are the steps of fracture management?
Resuscitate = save the patient's life, then worry about the fracture Reduce = bring bone back together in an acceptable alignment so soft tissue is no longer being violated by jagged edge of broken bone = reduced pain and also prevents further blood loss Rest = hold the fracture in position to prevent distortion or movement how fracture in great / acceptable position to prevent distortion or movement Rehabilitate - get function back and avoid stiffness - prevent muscle atrophy during the time frame of bone healing = physiotherapy v. important
30
What are the consequences of immobility?
Functional limitations = depending on where the injury is, cannot walk, cannot use an arm, etc. Support needs = transport, catheters, daily needs from limitations VTE (venous thromboembolism) prophylaxis Required wider MDT support
31
What are the conservative fracture management options?
PRICE - protect, rest, ice, compress, elevate Non-operatively use circumferential, plaster or fibreglass casts If an area cannot be cast - use a splint Or use traction = important in long bones e.g. femur, humerus = sticky thing attached onto limb and weights attached to end hanging off = gravititation weight too - realigns the fracture
32
Why are definitive (e.g. circumferential) casts not good?
Swelling - acute injuries tend to swell Pushes against structures within body - blood flow can be compromised Leads to compartmental syndrome
33
What are surgical fracture management options?
MUA + K-wire = reduces with patient under anaesthesia = useful in children due to thick periosteums preventing fracture aligment from holding in place (displacement common) ORIF = Open Reduction Internal Fixation IM nail = intramedullary nails = useful for long bone fractures - insufficient soft tissue coverage for extramedullary methods but can be very dangerous since you can disrupt the physiology of a patient External fixation = - Mono/biplanar = sits within one or two planes = goes in from outside the skin - apply rods on the outside and build a construct that allows for stability of the fracture pattern = used often in open fractures where there is poor soft tissue coverage OR - Multiplanar = ring fixation = when other methods have failed and patient is non-compliant with intramedullary methods = use of computer tomography to say where to place the pins = multiplanar construct thats more stable
34
How do you diagnose a fracture?
History and examination - tenderness / limb / pain / swelling Obtain x-ray of affected region, ensure in at least 2 different planes
35
How do approach orthopaedic X-rays?
``` Projection = at least 2 views / planes Patient details Technical adequacy Obvious abnormality Systematic review of X-ray Summarise ```
36
What is important when checking patient details?
NHS number | 2 people may have the same name