Bone pathology Flashcards
Identify these two types of bone?
Left: woven bone
Right: lamellar bone
Define a fracture?
A disruption in the integrity of a living bone
How can fractures be classified?
Complete vs incomplete
Dsiplaced
Comminuted
Open vs closed (compound vs simple)
Munted
Stress
Pathological
Describe the difference between a complete and incomplete fracture?
Complete: break all of cortex
Incomplete: just break one side of cortex
Describe a comminuted fracture?
Multiple bone fragments
Define a stress fracture?
How are they detected?
Repeated low force injury to a normal bone
Use bone scan to see where tissue is active
Define a pathological fracture?
A fracture that occurs in abnormal bone (e.g. osteoporosis, metastases)
What are the stages of fracture healing?
1) Haematoma formation
2) Soft callus formation
3) Hard callus formation
4) Remodelling
Describe the haematoma stage of fracture healing?
How long does this stage last?
Fibrin mesh creates framework
Platelets and leukocytes release inflammatory cytokines >
- granulation tissue
- bone cells activated
Variable necrosis
Lasts hours-days
Describe the soft callus stage of fracture healing?
How long does this stage last?
Fibrocartilage formation > holds ends together
Periosteum repairs itself over the outside
Lasts days to weeks
Describe the hard callus stage of fracture healing?
How long does this stage last?
Cartilage removal > osteoid formation > woven bone (endochondral ossification)
Lasts weeks to months
Describe the remodelling stage of fracture healing?
How long does this stage last?
Woven bone transformed into lamellar bone
Result is completely reconstituted bone
Lasts months to years
Describe the components of fracture healing present in this image?
Haematoma (left, dark purple)
Granulation tissue (next to haematoma)
Describe the difference in fracture healing when the two ends of the fracture are closely apposed?
May not need soft callus at all
Faster healing
Similar to intramembranous ossification
Describe the clinical management of a fracture?
Union of broken ends by:
- minimising the gap
- minimising the strain or movement (fixation)
Minimise any factors that slow healing (poor blood supply, infection, smoking)
List the factors that slow fracture healing?
Age > 40 yo
Comorbidities, especially diabetes
NSAIDS or corticosteroids
Smoking
Poor nutrition
Open fracture
Poor blood supply
Multiple traumatic injuries
Local infection
Describe some of the complications of fracture healing?
Non-union: fracture will not heal, despite persistent primary management
Delayed union: fracture does not heal as fast as expected
Mal-union: healing of a bone in an unacceptable position
Infection > osteomyelitis
Osteonecrosis: ischaemic bone when blood supply damaged
What is Paget’s disease?
Large, overactive osteoclasts
Osteoblasts produce more bone
Results in thick soft cortex and coarse trabeculae
What are the three stages of Paget’s disease?
Osteolytic: many osteoclasts
Mixed: bone breakdown and building
Osteosclerotic: heavy bone, abnormal structure, osteoclasts wear out
Describe the presentig symptoms of bony mets?
Pathological fracture
Hypercalcaemia
Bone marrow failure
Bone pain
Describe how malignant cells influence bone?
Malignant cells produce RANKL or PTHrP
Do not influence bone directly
Which primary tumours commonly give rise to bony mets?
Breast
Bronchus
Byroid
Bidney
Bostate
(rarely, bowel)
