Management of Specific Fractures Flashcards
What is bone?
Connective tissue that has a unique histological composition
What are the 5 functions of bone?
- Support = framework and shape of the body
- Protection = surrounds major internal organs and vasculature
- Locomotion = joints to allow flexibility and attachment site of muscles
- Haematopoesis = reservoir of stem cells forming blood cells
- Lipid and mineral storage = adipose tissue stored within bone marrow and calcium within hydroxyapatite crystals
What are 5 different types of bone?
- Flat bones - protect internal organs e.g. skull, thoracic cage, sternum, scapula
- Long bones - support and facilitate movement e.g. humerus, radius, ulna, metacarpals
- Irregular bones - vary in shape and structure e.g. vertebrae, sacrum, pelvis – pubic, ilium or ischium
- Short bones - no diaphysis, as wide as they are long, provide stability and some movemente.g. carpals, tarsals,
- Sesamoid bones - embedded within tendons, allows for dynamic action, also protects tendon from excessive stress / wear e.g. patella
What is the anatomy of the long bone?
Epiphysis = end
Metaphysis
Diaphysis = main body of the bone
What is found in the cross section of bone?
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
What are the 2 bone ultrastructures of bone?
- 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 - 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
What is the ultrastructure of compact (cortical) VS spongy (cancellous) bone?
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
What are the biochemical and structural support components that make up the extracellular matrix of bone?
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
What are the cellular components of bone?
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
How does bone ossify (i.e. grow)?
2 methods:
- Endochondral =
Formation of bone onto a temporary cartilage scaffold e.g. hyaline cartilage replaced by osteoblasts secreting osteoid in femur = provides length - Intramembranous =
Formation of bone directly onto fibrous connective tissue e.g. temporal bone or scapula = provides width to bone
How does the blood supply between bone and cartilage differ?
Bone has very good blood supply compared to cartilage
Once bone is formed, what happens?
Constant state of turnover - remodelling
How does bone remodelling work?
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
How are osteoblasts activated?
PTH
Where do osteocytes form from?
From osteoblasts, which lay down concentric lamellae and form osteons
Why is bone remodellling relevant cliincally?
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
What is a fracture?
Discontinuity of bone
What are the 4 key points in describing a fracture clinically?
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
Why do we classify fractures using those 4 points?
Improves communication
Assists with prognosis and treatment
What are the 3 different classification systems?
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
What is the AO/OTA classification system?
Number for bone
Number for where (proximal/distal)
Number for subgroup of type of fracture
What are the 2 types of fracture healing?
Primary (or direct) bone healing
Secondary (or indirect) bone healing
What is primary (or direct) bone healing?
Intramembranous healing, occurs via Haversian remodeling
Little (<500mm) or no gap
Slow process
Cutter cone concept – like bone remodelling
What is secondary (or indirect) bone healing?
What are the 4 steps of secondary bone healing?
- Endochondral healing, involves responses in the periosteum and external soft tissues
- Fast process resulting in callus formation (fibrocartilage)
- Haematoma formation =
Damaged blood vessels bleed forming a haematoma, neutrophils release cytokines signaling macrophage recruitment - Soft callous formation =
Collagen and fibrocartilage bridge the fracture site and new blood vessels form - Hard callus formation =
Osteoblasts, brought in by new blood vessels, mineralise the fibrocartilage to produce woven bone - Remodelling =
Months to years after injury osteoclasts remove woven bone and osteoblasts laid down as ordered lamellar bone
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
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
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
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
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
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
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
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
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
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
How do approach orthopaedic X-rays?
Projection = at least 2 views / planes Patient details Technical adequacy Obvious abnormality Systematic review of X-ray Summarise
What is important when checking patient details?
NHS number
2 people may have the same name
