T&O: general Flashcards
Name the different classifications of fracture based on how they appear
What are the 3 most common sites for avascular necorosis?
Neck of Femur (intracapsular)
Scaphoid (Carpal bones)
Talus (most superior of tarsal bones)
Which 5 organ cancers most commonly metastasies to bones?
Breast
Prostate
Kidney
Lungs
Thyroid
What is a pathological fracture? What are some examples?
A Pathologic fracture is when the force or impact didn’t cause the break to happen. Instead, an underlying disease leaves your bones weak and brittle. You may move wrong or shift your body weight in a way that puts pressure on weak bones.
E.g. Osteoperoisis
Pagets disease
Osteomalacia
Osteogenesis imperfecta
Ostetoitis
Benign bone tumours
Primary malignant bone tumour / secondary malignant bone mets
If suspect a pathological fracture what changes would you make to your investigations?
Ensure full length femoral Xray - ensure no other fractures
Name three functions of bone
Mechanical - protect delicate tissues and organs, a framework for the shape of the human body, form a basis for movement.
Synthetic - haemopoiesis.
Metabolic - mineral storage (ca2+, po4-), fat storage (yellow bone marrow), acid-base homeostasis by absorbing salts to regulate blood pH
What is the difference between endochondral ossification and intra-membranous ossification?
Endochondral - form long bones from cartilage templates. Have continued lengthening by ossification at the epiphyseal plates. Intra-membranous ossification - the formation of bone from clusters of mesenchymal stem cells in the centre of bone.
Describe a coronal section of mature bone
Compact/cortical bone on the outside/external surface. Cancellous bone/spongy on the inside - combines strength with lightness.
Name a factor which affects bone stability
Activity of osteocytes (can act as osteoblasts or osteoclasts).
Activity of osteoblasts (stimulated by calcitonin, GH, oestrogen, testosterone, thyroid hormones, vit A)
Activity of osteoclasts (increased by PTH).
Nutrition - vit D, C, K and B12.
In a fracture repair, first comes hematoma formation. Next comes ______(1)_______, followed by bony callus formation and ______(2)________.
(1) - fibrocartilaginous callus formation - here, the pro callus of granulation tissue is replaced by a fibrocartilaginous callus where bony trabecular are developing.
(2) - bone remodelling - cancellous bone is replaced by compact, cortical bone until bone remodelling is complete.
Define osteomalacia
Softening of bone due to vitamin D deficiency. This increases the risk of bone fractures in older adults.
Why does prolonged steroid use increase the risk of fractures?
Steroids decrease osteoblast activity and increase osteoclast activity. This reduces bone density and increases risk of osteoporosis. Increased risk of osteoporosis = increased risk of fracture.
Osteogenesis imperfecta affects 4 parts of the body - what are they?
B = bones
I = eyes
T =.teeth
E = ears
What is the mechanism of action of bisphosphonates?
Inhibition of osteoclasts
Describe the five stages of healing in fracture healing
- Haematoma: tissue damage and bleeding occur at the fracture site; bone ends die back a few mms.
- Inflammatory reaction: inflammation cells appear in the haematoma.
- Callus formation: cell population changes to osteoblasts and osteoclasts; dead bone is mopped up and woven bone appears in the fracture callus.
- Consolidation: woven bone is replaced by lamellar bone - fracture has united.0
- Remodelling: newly formed bone is remodelled to resemble the normal structure.
