Unit 6A - Fractures, Fracture Healing & Non-Surgical Fixation

Question 1

Name 3 functions of bones?

Answer 1

1. Protect and support internal organs
2. Carry load
3. Enable locomotion

Question 2

The location and mode of fracture are determined by what?

Answer 2

1. The geometry and structure of the bone
2. The loading mode, such as compression, bending, and torsion
3. The loading rate

Question 3

Name 5 types of fracture?

Answer 3

Transverse
Oblique
Butterfly
Spiral
Comminuted

Question 4

Name the 5 steps of the fracture process?

Answer 4

1. Energy is delivered to the limb
2. Energy is transferred via soft tissue to the bone which absorbed the energy
3. Bone breaks and energy is released back to the soft tissues
4. The broken bone and damaged soft tissues bleed and cause a build up of blood around the damaged area - Haematoma
5. An acute inflammatory response occurs around the damaged area

Question 5

If there is excessive movement at the fracture sit what is laid down rather than bone cells?

Answer 5

Cartilage

Question 6

Describe weeks 0-2 of the natural fracture healing process?

Answer 6

The haematoma is invaded by macrophages in surrounding tissue which are responsible for “mopping up” dead and damaged tissue. The haematoma and dead cells are absorbed into the macrophages

Question 7

Describe weeks 2-6 of the natural fracture healing process?

Answer 7

New capillaries grow into the fracture haematoma bringing with them cells of healing and repair including fibroblasts, which form fibrin (scar tissue) and also other cells including osteoblasts

Question 8

Describe weeks 6-12 of the natural fracture healing process?

Answer 8

New bone is laid down in the endosteal space from residual living bone and eventually the 2 ends are reunited as a ball of “provisional callus” which appears as a dense area on x-ray

Question 9

Describe up to 12 months of the natural fracture healing process?

Answer 9

If circumstances are correct the provisional callus continues to form woven bone which gradually remodels to form a cortex

Question 10

Describe up to 2 years of the natural fracture healing process?

Answer 10

The callus matures so that the trabecular pattern is reformed and the bone remodels to accommodate the stresses that the bone experiences in the anatomical region

Question 11

What is Wolff’s law?

Answer 11

Bone has the ability to remodel, by altering its size, shape, and structure, to meet the mechanical demands placed on it

Question 12

Name 3 possible factors which may explain why movement at the fracture site influences bone healing?

Answer 12

1. Piezoelectric effects
2. Hormonal factors
3. Electromagnetic effects

Question 13

Name 3 forms of external fixation?

Answer 13

1. Plaster of Paris and its derivatives
2. Traction
3. External fixator

Question 14

Name 3 forms of internal fixation?

Answer 14

1. Bone screws
2. Bone screws and plates
3. Intramedullary nails

Question 15

What does plaster of Paris consist of?

Answer 15

Chrystals of calcium sulphate

Question 16

Name an accelerator used to speed up the setting process of a plaster of Paris?

Answer 16

Starch - also allows calcium sulphate to “hold on” to the bandage

Question 17

Name retarders which can be used to slow down the setting process of a plaster of Paris?

Answer 17

Alum

Borax

Question 18

Plaster of Paris is made up of 2 types of crystals, some are long and sharp and others are shorter. The longer crystals occur naturally as what?

Answer 18

Alabaster

Question 19

Name 2 classes of new materials used as alternative materials to plaster of Paris?

Answer 19

1. Polycaprolactone/isoprene sheets

2. Fibre/polyurethane composites

Question 20

Name the 3 types of traction?

Answer 20

Static
Dynamic
Balanced

Question 21

What is the commonest form of traction?

Answer 21

Dynamic traction

Question 22

Name 5 disadvantages of traction?

Answer 22

1. Bed sores
2. Chest infections
3. Urinary infections
4. Disuse atrophy of muscles and bone
5. Requires long stay in hospital (normally up to 3 months)

Question 23

Name 4 factors to consider when choosing a method of holding a fracture?

Answer 23

1. The patient
2. The injury
3. The facilities available
4. The ability of surgeon