[The ankle and hindfoot of rheumatoid arthritis patients: study with computerized tomography]

To study ankle and hindfoot involvement, we used Computed Tomography (CT) in 38 rheumatoid arthritis (RA) patients (32 women, 6 men, mean age: 56.3 +/- 10.1 years, mean disease duration: 9.9 +/- 6 years) all presenting a definite clinical disease of these joints. The scans were performed on 3rd generation CT equipment (GE ProSpeed SX), with coronally oriented scans 3 mm thick. Bone erosions and joint space narrowing (present/absent) of both talocrural and posterior talocalcaneal joints were assessed and heel valgus angle was measured. Ankle changes (erosion plus joint narrowing) were observed in 15 patients (39.5%, 17 of 76 lower limbs), talocalcaneal changes in 18 (47.4%, 31 lower limbs) and valgus deformity of the hindfoot in 22 (57.9%, 40 lower limbs). Involvement of talocrural and talocalcaneal joints as well as alignment abnormalities were symmetrical in 13.3%, 77.8% and 81.8% of the cases, respectively. All the CT findings were significantly related to disease duration (p = 0.02) and hindfoot injuries to Ritchie index too (p < 0.05). No relationship with seropositivity was observed. Our study confirms that radiographic changes do not entirely mirror clinical evidence and shows that CT does not represent a routine examination for RA patients, but could be reserved to those with prolonged disease or severe heel deformity to plan surgery.