Ilizarov

Ilizarov Frame Proximal Tibia Clinical Photo

 

Indications

 

Poor soft tissues

- prohibit ORIF

 

Non union

 

Infected non uniion

 

Malunion / deformity

 

Bone loss / bone transport / LLD

 

Concept

 

Concept is known as flexible stability

 

Ilizarov Frame

- controls torsion and shear well

- allows axial compression and controlled micromotion

- this improves bone healing compared to standard external fixation

- tensioned wires tend to loosen over time and improve this situation with further loading

 

Can compress / lengthen

- lengthen and shorten struts

- allows compression of non union

- allows distraction osteogenesis of corticotomies

 

Components

 

1.  High tension wires

- straight or olive

- 90 - 130 kg

- 90o to each other

 

Olive wires

- used to aid indirect reduction

 

Tension

- fix one end, tighten the other

 

Offset wires from rings

- using posts

 

2.  Pins

 

Use in conjunction to wires

- never at same level as each other to avoid stress riser

- 90o to each other

- 4, 5 or 6 mm

- connected to ring via rancho cubes with centering sleeves

 

At least 2 planes of wires / half pins in each major bone segment

- very normal to use 1 tensioned wire and two HA coated half pins

- if have 3-4 wires / half pins can remove 1 (i.e. from loosening or infection) without loosing stability of construct

 

3.  Rings

 

Various sizes

- always need extra room posteriorly

- 2-3cm space to skin circumferentially

- proximal ring open posteriorly to allow flexion

- always 2 level fixation in each level for control

- can be one ring, but wires & half pins above and below

 

Stability

 

Techniques

- spread wires

- thicker wires (1.5-1.8)

- increase number of wires

- closer to fracture site

- increase tension

- smaller rings (only 2cm gap)

- olive wires

 

Wire placement

 

Anatomic Safe Zones

 

Aim is to avoid NV structures

- start on side containing critical structures

- push in to bone, drill through cortices

- wet gauze square to stabilise wire

- tap through soft tissue on other side

- muscles on maximus stretch to prevent impalement

- parallel to each other and to ring

- two rings in each segment

 

Proximal Tibia

 

Structures at risk

- CPN
- popliteal artery and tibial nerve

- saphenous nerve

 

Wires Proximal to TT

- safe arco degrees

- 3 wires

- one wire anterior to fibular head angled anteriorly

- one wire through fibular head straight across posterior tibia

- one wire through medial posterior tibia angled anteriorly

- creates a triangle of bone between wires

- always 10 - 15 mm distal to joint line to avoid proximal joint capsule

- can supplement one wire with two half pins below (HA coated) in the medial cortex

 

Wires Distal to TT

- safe arc 140o

- not safe to go through fibula

- direct wire transversely

 

Schatzker 6 Proximal TibiaIlizarov Proximal TibiaIlizarov Proximal Tibia Lateral

 

Distal Tibia

 

Structures at risk

- SPN

- DPN and anterior tibial artery

- posterior tibial artery and tibial nerve

- saphenous nerve

 

Wires

- one wire through fibula head angled anteriorly

- one through posterior medial tibia, angled anteriorly

- one straight across

- again supplement with half pins above and below

 

Ilizarov Distal Tibia ClinicalIlizarov Distal TibiaIlizarov Distal Tibia Lateral

 

Complications

 

Good pin site care is aided by avoiding loosening

- pin site complications are frequently related to loosening

 

Pin site infection

 

Reduce by

- subcutaneous (don't go through muscle)

- away from zone of injury

- adequate skin incisions

- predrill to avoid thermal necrosis

- manually insert pins

- HA coating

- regular pin site cleaning 

- early oral Abx

 

New self drilling pins are designed for motorised insertion

- avoids problem of "wobble " with hand insertion

 

HA coating

- improves fixation and decreases infection / loosening

 

Tapered pins

- increase preload and decrease loosening

- cannot back the pin up or become loose

 

Pin site care

- motion of skin is most deleterious

- leave a compressive dressing intact for 1 week

- simple daily showers with soap sufficient

 

Pin site infection

- must remove if loose

- oral Abx

- more regular cleaning

- topical bactroban (mupirocin)

 

Soft tissue impalement

 

Effects

- loss of motion

- scarring

 

Prevention

- check ROM intraoperatively

- position joint in neutral

 

Late Malunion / Refracture

 

Dynamise frame / remove struts

- allow patient to weight bear in frame

- should be non painful