Lecture 1 - finished Flashcards

1
Q

What is the healing timeline for fractures

A

Haematoma formation - first 2-3 days
Acute inflammation - first 3-5 days
Granulation tissue/ procallus formation - 3-7 days post fracture
Fibrocartilagenous callus formation - starts 1 week post fracture and lasts up to 3 weeks
Bony callus formation - starts 3-4 weeks post fracture and finishes about 2-3 months later
Remodelling - starts during bony callus formation and continues for several months

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2
Q

Fracture definition

A

A break in the continuity of bone

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3
Q

Clinical manifestations of OM in adults

A

Insidious onset of:

  • vague ssx
  • fever
  • malaise
  • anorexia
  • weight loss

Recent Hx of:

  • Infection
  • Instrumentation
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4
Q

Stages of fracture healing:

A

Stage 1: Fracture occurs

Stage 2: Haemorrhage and haematoma formation
- extravasated blood clots to form a haemotoma
- inflammation is initiated
- Activation of local inflammatory cells and migration of these cells into the region
- Activation and proliferation of local connective tissue cells
= Osteoblasts, osteogenic cells, fibroblasts, chondroblasts

Stage 3: Procallus formation/ organisation of the haematoma
- Haematoma is replaced by granulation tissue
- In this stage:
= Phagocytes remove debris
= Osteoblasts make woven bone (limited because of slow neovascularisation rate)
= Fibroblasts make collagen
= Chondroblasts make cartilage
= Blood vessels grow into the region

Stage 4: Fibrocartilagenous callus

  • All cells within the procallus makes massive amounts of cartilage and collagen
  • Woven bone is formed but still limited
  • As the cartilage and collagen amounts increase the granulation tissue gives way to fibrocartilagenous tissue.

Stage 5: Bony Callus formation
- In this stage we see:
= increased neovascularisation
= increasing mineralisation of osteiods
= destruction of fibrocartilagenous tissue by osteoclasts
= increased synthesis of woven bone
- This forms a bony callus which reunites the ends of fracture.

Stage 6: Remodelling

  • In this stage osteoclastic activity is greater than osteoblastic activity
  • Woven bone is destroyed and replaced with lamellar bone (which is laid down in concentric layers to form osteons)
  • Internal and external calluses are reabsorbed.
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5
Q

Diagnosis of osteomyelitis

A
Hx and clinical exam
Biopsy: needle aspiration
Blood tests: 
- cultures (+ve in 50% of cases)
- Increased WBC, CRP and ESR 

Imaging:

  • Radiography (bone infection not evident for 14-21 days)
  • MRI (good for early detection)
  • Radionuclide bone scanning
  • CT
  • US
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6
Q

Complications of #

A
Delayed union
Non union
Pseudarthrosis
Malunion
Bone necrosis
Compartment syndrome
Fat embolism
Infection
Shock
Local soft tissue injury
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7
Q

Local causes of delayed healing time

A
Malalignment
Excessive movement
Comminution
Bone disease
Severe soft tissue injury
Infection
Ischemia
Soft tissue interposition
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8
Q

What is the definition of a pathological fracture?

A

When a small/moderate force acts on a weakened of diseased bone causing a fracture

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9
Q

Clinical manifestation of vertebral OM

A

Back pain:

  • Intermittent or constant
  • worse with motion
  • throbbing at rest
  • -/+ radicular distribution

Spinal tenderness and rigidity
Hip contracture secondary to psoas irritation

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10
Q

Why is fracture classification important?

A
So we can assess: 
Occurrence (how it happened)
Seriousness
Type of treatment required
Prognosis
Complications
Stability of fracture
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11
Q

Osteomyelitis definition

A

Inflammation of bone caused by bacteria

occasionally caused by mycobacteria or fungi

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12
Q

Pathogenesis of osteomyelitis in children

A

Transient bacteremia

Bacteria reach the bone

Inflammation of bone
- inflammation spreads through haversian canals and causes compression of adjacent blood vessels.

Bone necrosis and abscess formation

Sequestrum
- dead bone separates from living bone

Reactive bone growth:

  • inflammatory exudate may extend to the surface of the cortical bone; abscesses and oedema form and cause elevation of the periosteum.
  • periosteal elevation disrupts the blood supply to the bone in that area and deprives underlying bone of blood supply
  • lifting of the periosteum also stimulates intense osteoblastic activity which results in the formation of new bone (involucrum) which may surround the affected bone.

Sinus formation:

  • pus and necrotic tissue from the infection focus may drain towards the surface of the skin.
  • superficial drainage site is called the cloaca.
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13
Q

Local ssx of #

A
  • Deformity
  • Oedema
  • Pallor
  • Bruising/erythema
  • Loss of function
  • Palpation will reveal - pulselessness, tenderness, paresthesia
  • Movement will reveal - crepitation, muscle spasm, abnormal movement
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14
Q

OM on plain film x-ray

A

First manifestation:
- soft tissue oedema 3-5 days post infection
Bony changes:
- initial periosteal elevation
- subperiosteal bone formation (involucrum)
- cortical and medullary radiolucencies as bone is destroyed

(** remember that bone loss has to be 40-50% for it to be evident on x-rays)

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15
Q

Causes of Physiological Fractures

A

Fatigue
Accident
Unusually strong muscle contractions
Prolonged/repetitive physical stress

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16
Q

Signs of fat embolism

A
Hypoemia
Tachypnoea
Fever of unknown origin
Chest pain
Altered mental status
Possibly petechiae
17
Q

Classification types for fracture

A

According to aetiology

  • physiological
  • pathological

According to the site of force on the bone

  • direct
  • indirect
According to visual characteristics
- spiral
- transverse
- oblique
- chip
etc
According to the extent of the fracture
- greenstick
- comminuted (many pieces)
- complete (2 pieces)
etc

According to whether the overlying skins is broken

  • simple
  • compound (broken overlying skin)

According to joint involvement

  • intracapsular
  • extracapsular

Common fractures:
Colles - distal radius
Potts - eversions sprain causing avulsion of med mal and fracture of lat mal

18
Q

Define cloaca:

A

Superficial drainage site for the focus of infection in the underlying bone in OM

19
Q

Systemic causes of delayed healing time

A
Mineral deficiency
Vitamin deficiency
Comminution
Systemic infections
Bone disease
Ischemia (atherosclerosis)
Endocrine disease
Medications
Poor general health
Advanced age
20
Q

Clinical manifestations of OM in children

A

Sudden onset of high fever, chills and nausea
Progressively increasing local pain
Local muscular spasm
Local oedema and warmth of the soft tissues

21
Q

General ssx of #

A

Shock
Ssx secondary to other organs damaged eg viscera, CNS
Ssx due to underlying pathology

22
Q

6 signs of compartment syndrome

A
Pain
Pulselessness
Perishingly cold
Paraesthesia
Paralysis
Pallor
(Pressure increase)
23
Q

What are the differences in bone usually affected by OM between children and adults?

A

Adults: usually spine, pelvis or small bones
Children: usually the metaphysis of long bones

24
Q

Fracture epidemiology

A
Young people - 15-24
- tibia
- clavicle
- lower humerus
Usually secondary to trauma
Old people - 65+
- Upper femur
- upper humerus
- vertebrae
- pelvis 
Usually secondary to osteoporisis
25
Q

What affects bone healing times

A

Age
Type of #
Bone #’d
Health of patient

26
Q

What is the most common scenario for osteomyelitis?

A

Haematogenous spread of staphylcoccus aureus from an unknown primary site

27
Q

Pathogenesis of osteomyelitis in adults

A

Transient bacteremia

Bacteria reach the bone

Inflammation of bone
- inflammation spreads through haversian canals and causes compression of adjacent blood vessels.

Bone necrosis and abscess formation

Sequestrum
- dead bone separates from living bone

28
Q

What are the main forms of spread of bacteria into bone?

A

Contiguous

  • dental
  • cutaneous
  • sinus
  • aural

Traumatic

Haematogenous

29
Q

Causes of Pathological fractures

A

Focal bone disease
Metabolic disorders
Disuse

30
Q

Do adults get the reactive bone growth and sinus formation stages of OM?

A

No, because the periosteum is firmly attached to the bone cortex in adulthood and resists displacement

31
Q

What is the definition of a physiological fracture?

A

When a strong external force acting on a normal bone exceeds the mechanical strength of the bone