- Pseudarthrosis:
- a major complication;
- consdier managing patient nonoperatively w/ orthosis;
- w/ operative treatment consider if old incisions can be used;
- acquired pes valgus, metatarsalgia, or other complication may occur;
- Malaligned Fusion:
- significant problems arise when the fusion position is incorrect;
- genu recurvatum, or backknee, will result from a plantar-flexed foot;
- heel lift may compensate for moderate plantar flexion (5-10 deg),
but significant problems arise with excessive plantar flexion;
- to avoid vaulting over plantar-flexed foot, patient must turn leg out,
& secondary medial collateral laxity can occur;
- if foot is translated medially or laterally, other subtalar and
gait problems can occur;
- when subtalar joint is inverted or in varus position, transverse tarsal
joint is locked, making rigid foot that needs to be vaulted over;
- case example:
70 year male who underwent an ankle fusion for DJD following an ankle frx which occured in the distant past;
- the initial fusion attempt w/ crossed screws made no attempt to control rotatory forces (which
is usually obtained w/ a screw directed into talar head - from posterior to anterior);
- after 6 months it was clear that the fusion had failed, w/ lysis around the screws and gross motion at the ankle joint;
- this fusion was salvaged w/ a revision fusion consisting of:
- excision of the fibula for exposure and source of bone graft (along w/ ICBG);
- recutting the distal tibia and talus;
- application of an EBI fixator (w/ one talar pin and one calcaneal pin) which facilitated positioning of the ankle,
temporary compression across the ankle joint (while screws were inserted), and which helped to control rotatory forces;
- insertion of two Synthes 7.3 cannulated screws from the sinus up into the distal tibia, as vertically as
possible (which would allow for some additional impaction across the ankle once the patient begins walking);
- once the screws were inserted, the external fixator compression was partially released inorder to avoid compression across the subtalar joint;
