bone fracture healing Flashcards
What is the first stage of bone healing known as?
Fracture haematoma.
Haematoma formation
When does the first stage occur?
6-8 hours after the fracture has occurred.
Give a description of the events of the first stage of bone fracture healing. (9)
6- 8 hours after the fracture occurs
- Periosteum, Haversian canal, medullary cavity and blood vessels are damaged due to fracture.
- Blood pools around the injured site.
- Haematoma forms.
- periosteum is detached from the bone surface.
- Cells begin to die as blood supply is cut off.
- inflammation and swelling occur.
- the inflammation and swelling causes debris to be created
- phagocytes and osteoclasts remove cells debris
What is osteonecrosis?
Death of bone tissue due to disruption in blood flow.
What is the second stage of fracture healing? And how long does it last?
fibro-cartilaginous (soft) callus formation.
3 weeks.
What is the fourth stage of fracture healing?
remodelling
Describe an open fracture.
Bone penetrates the skin and exposed to external environment.
Describe a closed fracture
Bone does not penetrate the skin.
What are the two main kinds of fracture?
Open and closed.
Describe a transverse fracture.
Occurs on the transverse plane- straight across the bone.
Describe a comminuted fracture.
Bone has fractured into three or more parts.
Describe a greenstick fracture.
Bone has fractured but still intact. Usually in children still growing.
Describe a segmented fracture.
Bone is fractured into three separate parts so there is a floating part.
Describe a oblique fracture.
Bone is broken diagonally across.
Describe an avulsion fracture.
A section of the bone has broken off. Can occur in rolled ankles. Where a tendon has pulled too hard to break part of the bone off.
Describe a stress fracture and how it may occur.
Bone is cracked or has small breaks. Occurs from repetitive stress on the bone, or overuse.
Describe an impacted fracture.
bone breaks due to bone ends being jammed together due to extreme stress.
Describe a torus (buckle) fracture.
The bone periosteum is still intact but the bone inside is broken.
Describe the second stage of fracture healing. (7)
FIBROUS CARTILAGE (SOFT) CALLUS FORMATION
Lasts several weeks
- Blood vessels begin to grow as there is low oxygen concentration in the area.
- the blood vessels grow into the haematoma
- the haematoma is organised into granulation tissue called pro callus
- Fibroblasts from the periosteum appear and begin to build up collagen fibres.
- Chondroblasts appear and begin to produce cartilage
- The fibroblasts and chondroblasts strengthen the pro callus
Describe the third stage of fracture healing. (5)
BONY CALLUS FORMATION
- Lasts a couple of months.
- osteoprogenitor cells develop into osteoblasts (bone builder cells)
- These cells produce trabeculae.
- The trabeculae begins to join the two ends of the bone together.
- The fibrous cartilage is converted into spongey bone which strengthens the callus.
Describe the fourth stage of fracture healing. (3)
BONE REMODELLING
Can take months or years to return to orginal strength.
- dead bone is absorbed by the osteoclasts.
- compact bone replaces spongey bone.
- often the repair leaves the periosteum thicker than it was originally.
