Diagnostic injections of the hindfoot joints in patients with rheumatoid arthritis prior to surgical fusion

Although surgical fusion of the hindfoot can result in considerable reduction of symptoms in patients with rheumatoid arthritis, results can be unpredictable. Difficulty in identifying the symptomatic joint/joints despite the use of computerized tomography (CT) is one of the factors in this unpredictability. Using fluoroscopic control we have injected preoperatively 2–4 ml of 1% lignocaine and contrast media into either the ankle joint, the subtalar joint complex or both joints in 35 patients and prospectively assessed them clinically and with radiographs and CT. The ankle joint was injected initially and if symptom resolution was achieved the subtalar joint was not injected. The patients scored pain levels on an analogue scale from 0 to 10. A total of 82 joints were injected in 41 feet. The average pain score was 8.6 (5–10) before and 3.2 (0–9) after injection. The effect was often dramatic and in 13 feet (31%) was prolonged, lasting up to several months. In 16 (39%) the initial decision regarding arthrodesis based on clinical assessment and radiology was altered following the injection response. Diagnostic injection has an important role to play in association with clinical examination, plain radiographs and CT in the preoperative assessment of these patients.