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#3 Surg > 41 and 42 - External Fixation - Rings > Flashcards

41 and 42 - External Fixation - Rings Flashcards

1
Q

Indications for external ring fixation

A
  • Acute trauma

- Limb reconstruction

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2
Q

Ex fix ring for acute trauma

A

o Tibial articular fractures (pilon – convoluted distal tibial fracture, plateau)
o Tibial articular fractures with diaphyseal extension
o High energy diaphyseal fractures of tibia
o Calcaneal fractures (the calcaneus will fracture into numerous pieces)
o Ankle fractures

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3
Q

Ex fix ring for limb reconstruction

A 
o	Correction of post-traumatic, acquired and congenital deformities (multiplanar)
o	Arthrodesis (ankle, subtalar, tarsometatarsal)
o	Charcot
o	Non-union and bone loss
o	Joint Contracture in adults and children (ankle, foot) 
o	Arthrodistraction (ankle joint – due to osteoarthritis, foot)
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4
Q

Circular fixators

A
  • Used in monoplanar and biplane deformities
  • Ilizarov (Smith & Nephew)
  • Sheffield Ring (Orthofix)
  • Distraction and compression can be created at any site to which the fixator can be applied
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5
Q

Goals of screws and wires

**KNOW THIS ***

A

o Stability created with tensioned wires inserted into bone*
o Rigidity created with half pins screwed into bone*

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6
Q

Hybrid fixators

A
  • Combination of fixators (unilateral or circular)
  • KNOW THIS (test question***)…
  • ***Stability created with tensioned wired attached to circular frame
  • ***Rigidity created with half pins attached to circular frame and unilateral frame
  • Main use is for Pilon and Tibial Plateau fractures and ankle arthrodesis
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7
Q

Taylor spatial frame

A
  • Smith & Nephew
  • Orthofix
  • Reduction of tri-plane complex deformities
  • Articulated distractors and rings
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8
Q

Circular fixator construction

A
  • Uses transosseous tensioned wire
  • Wires
  • Smooth wires (FOCUS ON THIS)
  • Olive wires (used to reduce fractures or deformities – this is beyond this lecture)
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9
Q

Wires

TEST QUESTION

A

Transosseous wires (long wires that go all the way through the bone) are placed under tension and undergo a self-stiffening effect

  • Self-stiffening – if you have a loose wire between two poles, it would be very hard to walk on, but if you spread apart the poles, the wire would have more tension on it (become stiff)
  • Similar idea with these wires – the are very flexible until we put them under tension and they become very stiff (stiff enough to support body weight)
  • Increased stability in the bone-fixator interface
  • Optimal stabilizing position is 90 degrees to each other*****
  • Smaller angles maybe used, but there will be decreased stability, so we often have to then use an increased number of wires
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10
Q

Example of circular frame construction

A

Example:

  • Axial wires are inserted through tibia, calcaneus and metatarsal bases
  • Midface tibia wires were inserted as well as additional calcaneal wires

Notes

  • Note that safe zones exist for safe placement of wires
  • One end of wire attached to circular frame
  • Wire placed under tension with wire tensioner
  • Tension maintained on wire and other end attached to frame
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11
Q

Fixator management

A

Dressing applied in OR
o Alcohol, hydrogen peroxide or antibiotic ointment

Transosseous wire care
o Daily cleaning with alcohol or peroxide
o Betadine avoided (dries out the skin)
o Antibiotic ointment applied (where pins enter skin)

Removal of sutures or stables

May get fixator wet if drainage is minimal

Post-operative adjustment

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12
Q

Removal of a circular fixator

TEST QUESTION*

A

Dynamization
o Release of tension from the wires
o Allows the bone to strengthen with an increase in weightbearing force
o Decreases the potential for fracture***

Short leg cast with partial weightbearing if dynamization is not possible

NEED to know that it is important to prevent fractures *******

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13
Q

Minor complications

A
  • Edema (no ability to reduce swelling with Jones compression when there is an ex-fix)
  • Pin tract irritation
  • Pin tract infection
  • Fractured transosseous wires (bad angles or obesity)
  • Pain secondary to positioning of the wires (pin through muscle)
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14
Q

Edema

A

External fixation does not allow postoperative wound compression
o Hematoma
o Compartment syndrome (from so much swelling)
o Serous and hemorrhagic fluid around wires

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15
Q

Pin irritation

A
  • Can release tension at skin-wire interface

- Can occur if wire is inserted through muscle belly and contraction occurs

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16
Q

Pin tract infection

A
  • Infection differentiated from irritation with cultures (via bacterial cultures)
  • Treat with local wound care and oral antibiotics – try this before removing pin
17
Q

STUDY - infection incidence

A
  • Checketts, et al. “Pin Track Infection: definition, incidence, and prevention.”
  • Prospective study of 353 pin sites over 12 months
  • Patients seen weekly from post op until two months after fixator removal

Results:
o 55% of pin sites had no problems
o 100% of infections were classified as Minor (25% Grade I, 18% Grade II)
o 0% infections requiring fixator removal (NOT THE ONLY OPTION FOR TX***)

18
Q

What else did the study on infection incidence find?

A
  • Found screws closest to a joint (i.e. ankle) were most frequently affected
  • More movement of soft tissues at these areas – tell patients to make sure they are cleaning those screws closest to the joints as quickly as possible ****
  • Presence of screw threads outside of skin or open fractures did not have an increase in risk of infection
19
Q

REMEMBER - screws and wires

A
  • SCREWS give us RIGIDITY

- WIRES give us STABILITY

20
Q

Major complications

A
  • Nonunion
  • Osteomyelitis
  • Neurovascular injury
  • Joint Subluxation
  • Fracture
21
Q

Nonunion

A
  • Can occur with poor fixation construction (not enough wires to produce stiffness)
  • Distraction too quickly
  • Other factors (infection, smoking)
22
Q

Fracture

A
  • Can occur after removal of fixator
  • More common with half pins
  • Inadequate dynamization
23
Q

Joint subluxation

A
  • Can occur with large distraction distances

- Prevent with fixation distal to distracted joints

24
Q

Neurovascular injury

A
  • Safe Zones or corridors
  • Twist structures around wire during drilling
  • Can decrease by drilling wire through cortices and pushing through skin
  • Can occur with aggressive distraction

#3 Surg (12 decks)

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