- see
fracture healing:
-
External Fixators for Distal Radius Fractures:
-
External Fixators for Femoral Fractures:
-
External Fixators for Humeral Fractures:
-
External Fixators for Tibial Fractures: (
circular wire fiaxators)
- General Considerations:
- indications:
- damage-control orthopaedic frame: (temporary)
-
timing of orthopaedic surgery in the head injured patient
- definitive-treatment
frame:
-
limb-lengthening and reconstruction:
-
pin care protocol:
-
soft-tissue compartment should be placed on stretch and the skin should be released if needed so that there is no skin tension;
- pin sites are covered and pins are dressed with a pressure type dressing (spacers, bolsters, sponges);
- pin sites are left covered (avoid frequent examinations)
- Misc:
-
pin infections:
- pin drainage: expect that at least one pin (out of the entire group) will have drainage in 80% of cases;
- w/ worsening signs of inflammation and drainage can be managed with oral antibiotics;
- persistent drainage is not an indication for pin removal if there is no radiolucency around the pins;
- pin loosening: (5-7%)
- deep infection in 4%
- minor pin tract infection requiring removal of pins and curettage: 9%
- major pin tract infections requiring pin removal, curettage, and implantation of gentamicin impregnated PMMA beads: 3%
- ref:
External circular fixation: a comparison of infection rates between wires and conical half-pins with threads outside or inside the skin.
-
methods to enhance fixator stability;
-
pin loosening:
- pins used w/ external fixators often loosen at pin bone interface;
- this is due to local mechanical overload (surface resorption induced by micromotion), which tends to be more common in cortical bone
rather than in metaphseal bone;
-
methods to reduce pin loosening:
- radial preload can significantly reduce surface resorption;
- using core pin diameters which are mismatched 0.1 to 0.2 mm larger than the drill diameter (don't confuse pin diameter w/ core diameter);
- hydroxyapatite coated pins: (see
hydroxyapatite)
- provides better fixation and decreases frequency of loosening and infection;
- references:
- A comparison of hydroxyapatite coated, titanium coated, and uncoated tapered external fixation pins. An in vitro study in sheep.
A. Moroni MD et al. JBJS. Vol 80-A. No 4. Apr. 1988. p 547.
- Hydroxyapatite coating of threaded pins enhances fixation. G. Magyar et al. JBJS.Vol 79-B. 1997. p 487-489.
Chronic osteomyelitis in pin tracks.
The thermal effects of skeletal fixation-pin insertion in bone.
Comparison of osteotomy healing under external fixation devices with different stiffness characteristics.
External skeletal fixation of canine tibial osteotomies. Compression compared with no compression.
Comparison of the effects of compression plates and external fixators on early bone-healing.
General theory and principles of external fixation. F. Behrens. CORR. Vol 241. 1989. p 15-23.
A comparison of hydroxyapatite coated, titanium coated, and uncoated tapered external fixation pins. An in vitro study in sheep. A. Moroni MD et al. JBJS. Vol 80-A. No 4. Apr. 1988. p 547.
*
