MSK Pathology and Fractures Flashcards
Difference between a sprain and a strain?
Sprain = stretch +/- tear of ligament
Strain = stretch +/- tear of muscle/tendon
Define a fracture
Disruption in the cortex, trabecular bone or both
List the 7 most frequent patterns of bone fracture and describe them
- Transverse
- Linear
- Oblique non-displaced
- Oblique displaced
- Spiral
- Greenstick
- Comminuted
Difference between pathological and insufficiency fracture
Pathological fracture = fracture through a pre-existing lesion in the bone
Insufficiency fracture = fracture where the entire bone has been weakened
Both refer to situations where the incident would not have normally caused a fracture
What pattern of fracture is common in a stress fracture?
Stress fracture = accumulation of microfracture leading to true fracture. Can be abnormal stress on the bone e.g. sports.
Most commonly see linear fractures in stress fracture injuries.
Describe the model of fracture healing?
- Bleeding - bone is highly vascular
- Haematoma - blood clot triggers inflammatory stage
- Soft callus - haematoma is organised to form a soft callus (fibrin meshwork, fibroblast ingrowth)
- Hard callus - Mesenchymal cells in soft callus differentiate into chondrocytes that produce fibrocartilage and hyaline cartilage. Bone undergoes endochondral ossification, forming woven bone.
- Remodelling - over time, the bony callus undergoes remodelling and returns to full strength.
Describe some early and late complications of fractures
Early:
- Bleeding and haemorrhage
- Infection and sepsis
- Inability to bear weight and mobilise
- Ischaemia of bone and surrounding tissue
Late:
- Pulmonary embolism (thrombus, fat, marrow)
- Chronic osteomyelitis
- Joint problems
Outcomes of malunion/non-union?
Pseudoarthosis (false joint) is formed, leading to high risk of refracture.
Causes of abnormal fracture healing
- Malignancy
- Infection
- Poor blood supply
- Excessive gap or step
- Malnutrition
- Movement during healing process
