Computed tomography of the hindfoot with rheumatoid arthritis.

We are performing direct, coronally oriented computed tomographic (CT) scans of the subtalar joint in patients with rheumatoid arthritis. To date, 16 examinations have been performed in 14 patients, 5 of whom were scheduled to undergo subtalar arthrodesis. Scans were 4-7-mm thick and spanned the length of the subtalar joint. CT scans depicted and localized subtalar abnormalities clearly and precisely. On CT scans, patients showed a characteristic constellation of abnormalities including: soft tissue swelling, cartilage space narrowing, bony erosions, and a pes planovalgus alignment abnormality (consisting of increased heel valgus angulation, and a tendency toward flattening of the sustentaculum tali, and medial and downward slippage of the talar head). The clarity of the CT images facilitated the surgeon's pre- and postoperative evaluation. In particular, it was easy to plan the correction of the valgus deformity, anticipate any special requirements for reinforcing the articular surfaces, and assess the results of surgery. We conclude that coronal CT scans clearly demonstrate abnormalities and help the surgeon evaluate the rheumatoid hindfoot.