Evaluation of the result and consolidation of arthrodesis in the hindfoot using simple radiography versus computed tomography

Abstract

Objective:Arthrodesis of the hindfoot presents good results in the literature, but non­union significantly compromises the functional result. Simple radiographs are the traditional method for evaluating consolidation of arthrodesis, but studies have demonstrated low sensitivity in identifying non­union, when compared with computed tomography. Methods:During the period 2010 to 2014, 16 patients (17 feet) were evaluated retrospectively using the AOFAS score, the consolidation of arthrodesis in each joint of the hindfoot was analyzed by means of simple radiography and computed tomography. The percentage of consolidated joint surface was then calculated, comparing the two diagnostic methods. We used Pearson’s coefficient for the correlation between the percentage of consolidation observed in the computed tomography and the functional result. Results:The average AOFAS score was 69 points. We observed average scores of 90.3% of the area of radiographic consolidation in isolated subtalar arthrodesis; 76.4% for combined subtalar arthrodesis; and 83.8% for total analysis of subtalar arthrodesis. Talonavicular arthrodesis had 92.4% consolidation and 100% in calcaneocuboid. When we analyzed the consolidation with computed tomography, we observed 53.7% of consolidation for isolated subtalar arthrodesis, 35.7% for combined arthrodesis, 45.3% for total subtalar arthrodesis, 75.5% for talonavicular arthrodesis and 86.5% for calcaneocuboid arthrodesis. Pearson’s coefficient demonstrated a weak correlation between percentage of fusion and AOFAS score (r0.02). Conclusion:Arthrodesis of the hindfoot presents favorable results. However, simple radiography proved inferior to computed tomography in that an overestimation of the extent of consolidated area was observed.