- fracture healing:
- references:
- 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.
- indications:
- damage control orthopaedics: - timing of orthopaedic surgery in the head injured patient
- definitive-treatment frame:
- limb-lengthening and reconstruction:
- methods to enhance fixator stability
- specific fracture:
- external fixators for distal radius fractures:
- external fixators for femoral fractures:
- external fixators for humeral fractures:
- external fixators for tibial fractures: (circular wire fixators)
- Pin Care and Prevention of Complications:
- 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)
- 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%
- references:
- External circular fixation: infection rates between wires and conical half-pins with threads outside or inside the skin.
- Prevention and management of external fixator pin track sepsis
- Chronic osteomyelitis in pin tracks.
- Pin-site care: can we reduce the incidence of infections?
- Life- and limb-threatening infections following the use of an external fixator
- 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 vivo study in sheep.
- Hydroxyapatite coating of threaded pins enhances fixation.
- The thermal effects of skeletal fixation-pin insertion in bone.