[Terminal phalangeal osteosclerosis in rheumatoid arthritis]

Osteosclerosis of the terminal phalanges of the hand has been reported in the collagen diseases including rheumatoid arthritis (RA). The current study was made to clarify the significance of terminal phalangeal osteosclerosis in RA.

Hand x-ray films of 108 patients (male 13, female 95) with RA for more than 10 years were assessed by Halim's grading. Grade 2, (Distance between both cortices is < 1 mm but there is still an intermediate space discernible), and grade 3, (Complete fusion of both cortices, but the base of the terminal phalanx is open), were classified as the positive group. Grades 0 and 1 were classified as the negative group. Both groups were compared and sigma GS/D values was measured at terminal phalanges, middle phalanges and metacarpuses of right middle fingers using digital image processing method. sigma GS/D index was calculated as being equal to the ratio of sigma GS/D value of the terminal or middle phalanx to sigma GS/D value of the metacarpus.

Thirty cases (28%) were positive (male 1, female 29). Osteosclerosis of terminal phalanges usually appeared in more than two digits bilaterally. It was located as follows; thumb-1 case, index-13 cases, middle-24 cases, ring-51 cases, little-58 cases. Obliteration of the medullary space of middle phalanges was seen in 5 cases. No difference was observed between the positive and negative groups about sex, age, the mean value of C-reactive protein, the incidence of Steinblocker's class classification and the rate of seropositive patients. Osteosclerosis of terminal phalanges was observed at first consultation in 93% of positive cases. Osteosclerosis is expected to appear in the early phase of RA and to last for more than 10 years. sigma GS/D index of the positive group (1.03 +/- 0.24, mean +/- SD) was greater than that of the negative group (0.63 +/- 0.25) (p < 0.05).