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− | {{toplink
| + | #REDIRECT[[Fractures]] |
− | |backcolour =CDE472
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− | |linkpage =Musculoskeletal System - Pathology
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− | |linktext =Musculoskeletal System
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− | |maplink = Musculoskeletal System (Content Map) - Pathology
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− | |pagetype =Pathology
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− | |sublink1=Bones Degenerative - Pathology
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− | |subtext1=BONES DEGENERATIVE
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− | }}
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− | <br>
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− | ===Fracture classification===
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− | *'''Traumatic''' - normal bone broken by excessive force
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− | *'''Pathologic''' - abnormal bone broken by minimal or no trauma
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− | **E.g. due to [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]], [[Bones - hyperplastic and neoplastic#Neoplastic|bone neoplasia]]
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− | *'''Closed''' - overlying skin and soft tissue is intact
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− | *'''Compound''' - overlying skin and soft tissue are perforated
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− | *'''Comminuted''' - bone is shatteed at fracture site
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− | *'''Compresses''' - the ends of the fracture are impacted into each other
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− | *'''Avulsed''' - due to pull of a ligament
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− | *'''Transverse'''
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− | *'''Spiral'''
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− | ===Fracture repair===
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− | [[Image:Recent healing fracture.jpg|right|thumb|100px|<small><center>Recent healing fracture (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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− | *Fracture
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− | **Ruptured blood vessels -> haemorrhage and clot formation, some ischaemic necrosis
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− | ***Dead marrow liquefies and is phagocytosed
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− | ***Dead bone is removed by [[Bones - normal#Normal structure|osteoclasts]]
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− | ****Continues long after bone has been united by callus
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− | **[[Bones - normal#Periosteum and blood supply|Periosteum]] tears, fragments displaced
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− | *-> Haematoma formation, necrosis of any isolated fragments
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− | *-> Mesenchymal cells proliferate in haematoma - [[General Pathology - Chronic Inflammation#Granulation tissue|granulation tissue]]
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− | **Invading cells: endothelial, fibroblasts, osteoprogenitor
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− | *-> Loose collagenous tissue (primary callus)
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− | *-> Mesenchymal cells differentiate to [[Bones - normal#Normal structure|osteoblasts]] and chondroblasts
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− | *-> [[Bones - normal#Bone organisation|Woven bone]] (secondary callus)
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− | **External callus - from periosteum
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− | ***Periosteal growth eventually bridges the gap between the fracture ends
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− | ***Blood supply is outstripped
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− | ***Cartilage is produced instead of osteoid
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− | ***Blood vessels invade cartilage -> [[Bones - normal#Bone development|endochondral ossification]]
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− | ***Osteoid becomes ossified
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− | **Internal callus - from endosteum
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− | ***Rarely forms cartilage
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− | ***May occlude the medullary cavity
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− | **Osteoid remodelled by [[Bones - normal#Normal structure|osteoclastic resorption]]
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− | *-> Mature [[Bones - normal#Bone organisation|lamellar bone]]
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− | *Early reactive fracture repair may be mistaken for [[Bones - hyperplastic and neoplastic#Osteosarcoma (OSA)|osteosarcoma]] on biopsy
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− | ===Complications of fracture repair===
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− | *Malnutrition
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− | *Lack of adequate blood supply (leads to hypoxia)
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− | **Leads to excess cartilage in callus
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− | **Healing can still occur since this can turn to bone
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− | *Excess movement
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− | **Leads to excess fibrous tissue in callus adn formation of false joint (below)
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− | *Presence of necrotic bone (may form a sequestrum)
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− | *Poor alignment
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− | *[[Bones Inflammatory - Pathology|Bacterial infection]]
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− | ===Pseudoarthrosis===
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− | *False joint
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− | *Non-osseus union
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− | *From infection, poor imobilisation, avascularity, extensive tearing damage to periosteum
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− | *Composed of fibrous tissue
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− | *If mobility continues -> hyaline cartilage forms -> neoarthrosis (formation of new joint)
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− | *In [[Bones Metabolic - Pathology#Secondary hyperparathyroidism|''Osteodystrophia fibrosa'']], [[Bones Metabolic - Pathology#Osteomalacia|osteomalacia]] and [[Bones Metabolic - Pathology#Rickets|rickets]] - callus forms but does not mineralise
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− | ===Head and neck of femur fracture===
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− | *Vascularisation from joint capsule -> if complete separation -> bone and marrow undergo avascular necrosis
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− | *Fibrovascular tissue and osteogenic cells invade -> deposit new bone
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− | *Resorption of articular cartilage and subchondral bone -> '''osteoarthropathy''' commonly develops
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− | ===Sore shins===
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− | *Dorsal metacarpal disease of racehorses
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− | *In 2-3 year olds
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− | *Excessive compressive stress on dorsal cortex of third metacarpal -> microfractures
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− | *Hyperaemic overlying periosteum - -> new bone production to cover the lesion
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− | <big>Also see [[General Pathology - Healing and Repair#Repair in the Bones|'''General Pathology - Repair in the Bones''']]</big>
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