- Considerations:
- pin care:
- tissue motion impairs tissue resistance to infection;
- excess motion at pin skin interface can be reduced by wrapping sterile gauze between the pin clamp and skin;
- surgical sponges around pins may prevent the skin from pistoning up and down over the wire, thus reducing pin tract contamination;
- time for healing: (prognosis for healing)
- grade I Fractures: 4.7 months (8% require grafting)
- grade III Fractures: 8.8 months (71% require Grafting)
- 0.5 cm fracture gap: 12-18 months
- bone grafting:
- probably 40-60% of grade III fractures will require bone grafting;
- dynamization:
- exchange nailing:
- some recommend change to internal fixation after healing of soft tissues and all pin sites to avoid these complications;
- 8 to 12 weeks after injury as the ideal time for such conversion;
- wt bearing:
- amount of wt bearing should be proportional to frx stability;
- to minimize stress on the pins, full wt bearing should be avoided unless compression can be placed across the fracture site, w/ the majority of the axial load applied to bone;
- segmental defect or bicortical communution:
- minimal wt bearing is maintained in order not to loosen pin bone interface;
- hence only touch down wt bearing should be permitted to protect pin tracts from excessive motion and stress over load;
- Complications:
- angulation:
- angulation following fixator removal is one of the most common complications associated with external fixation;
- 8% loss of good alignment and average valgus angulation of 8 deg;
- this can be avoided by not removing fixator until adequate callus is present radiographically;
- this can be avoided by protecting the fracture with a cast;
- refracture: if external fixator is removed prematurely, refracture rate may be 10%;
- equinus deformity:
- loss of knee motion:
- non union:
- approx 5% (closed) and 12% (open);
- consider early fibulectomy to encourage healing;
- consider early prophylactic bone grafting for unstable fractures (major comminution, bone loss, open frx);
- bone grafting may be required in 20% of all patients;
- following frame removal 1/3 of patients require additional casting for an average of 5 months;
- pin problems:
- over half of external fixators will have at least one problematic pin;
- 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% (see osteomyelitis in the tibia)
- 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%
Tibial external fixation, weight bearing, and fracture movement.