External Fixation- Rings

Question 1

what are the indications for external ring fixation?

Answer 1

• aucte trauma: fx,

- reconstructive surgeries: Charcot, arthrodesis

Question 2

how is stability created in circular fixators?

Answer 2

tensioned wires that are inserted into bone

Question 3

how is rigidity created in circular fixators?

Answer 3

half pins that are screwed into bone

Question 4

what are wires for? what are pins for?

Answer 4

wires- for stability

pins- for rigidity

Question 5

what is the optimal position of wires?

Answer 5

have 2 wires 90 deg to each other

Question 6

where do axial wires insert thru?

Answer 6

tibia, calcaneus, and metatarsal bases

Question 7

which wires are put under the most tension?

Answer 7

tibial wires (1000-1200N) 
*then hindfoot wires (800N), then forefoot wires (600N)

Question 8

which wires are put under the most tension?

Answer 8

tibial wires (1000-1200N) 
*then hindfoot wires (800N), then forefoot wires (600N)

Question 9

what is dynamization?

Answer 9

release of tension from the wires; allows the bone to strengthen after a period of immobilization

Question 10

what are some minor complications with external fixation?

Answer 10

• edema
• pin tract irritation
• pin tract infection
• fractured transosseous wires
• pain secondary to positioning of the wires

Question 11

what are some major complications with external fixation?

Answer 11

1. non-union
2. osteomyelitis
3. neurovascular injury
4. joint subluxation
5. fracture