Abstract
Isolated arthrodesis of the subtalar joint has the advantage that it preserves some motion at the midfoot. In cadaveric studies, movement at the Talonavicular joint is reduced by up to 74% and at the Calcaneocuboid joint by up to 44%. This allows some midfoot flexibility, which would not occur with a triple arthrodesis.
There are several methods of performing a subtalar arthrodesis, broadly divided into extra or intra articular techniques, using structural or cancellous bone graft and a variety of fixation methods.
Earlier studies on primary arthrodesis have shown rate of non union from 0 – 6%. More recently, larger studies have reported higher rates of non union from 14 – 17%.
We present the results of 95 subtalar fusions performed with a standard technique, using one screw from the calcaneum to the talar dome, with 100% follow up.
Between 1993 and 2003 the senior author performed 105 subtalar arthrodeses. We performed a retrospective chart review. All patients with a primary subtalar fusion were included. All cases had been refractory to conservative therapy.
The senior author reviewed all patients until fusion had occurred or a diagnosis of nonunion was established. Fusion was diagnosed when the patient were pain free while fully weight bearing, with a clinically rigid subtalar joint and radiographs showing trabeculae crossing the arthrodesis. A CT scan was performed in all cases where nonunion was suspected, and the patient complained of persistent pain.
A total of ninety five subtalar arthrodeses were performed in ninety two patients. All were reviewed with clinical and radiological examination, until union had occurred or nonunion diagnosed. The average time to union was 5.0 months, range 3 – 12 months. The outcomes, graded using the method of Angus and Cowell, were 21 Fair, 7 Poor and 67 Good results
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