Rheumatoid wrist deformity and risk of extensor tendon rupture evaluated by 3DCT imaging.
OBJECTIVE
Extensor tendon rupture on the dorsum of the wrist is commonly seen in patients with rheumatoid arthritis (RA). It causes immediate dysfunction of the hand and surgical reconstruction is usually required. The purpose of this study was to clarify the risk of extensor tendon rupture by quantifying wrist deformity on three-dimensional computed tomography (3DCT) images.


METHODS
Three-dimensional CT images of 108 wrists in 102 patients with RA and 38 wrists in 38 healthy volunteers were analyzed retrospectively. All of the rheumatoid wrists had caused persistent pain for more than 6 months despite ongoing medical treatment. Extensor tendon rupture was noted in 49 wrists in 47 patients, and no rupture was noted in 59 wrists in 56 patients. The dorsal subluxation ratio (DSR) of the ulnar head and the carpal supination angle (CSA) were measured utilizing a new technique.


RESULTS
The average DSR and CSA in the rupture group (n = 49), the non-rupture group (n = 59), and the normal wrist group (n = 38) were 37%, 19%, and 26%, and 15 degrees , 11 degrees , and 6 degrees respectively. The cut-off values for extensor tendon rupture in the wrists of patients with RA were 32% (sensitivity; 70%, specificity; 75%) in the DSR, and 14 degrees (71%, 68%) in the CSA.


CONCLUSIONS
By utilizing 3DCT imaging of the rheumatoid wrist, these parameters can help improve our ability to predict extensor tendon rupture.
Department of Rheumatology, Niigata Rheumatic Center, 1-2-8 Honcho, Shibata city, Niigata 957-0054, Japan. med@ra-center.com
Hajime
H
Ishikawa
Asami
A
Abe
Akira
A
Murasawa
Kiyoshi
K
Nakazono
Hidehiro
H
Horizono
Katsushi
K
Ishii
Eiko
E
Seki
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D018570:Risk Assessment; D012421:Rupture / Q000000981:diagnostic imaging / Q000209:etiology; D012680:Sensitivity and Specificity; D013585:Synovitis / Q000150:complications / Q000000981:diagnostic imaging; D013708:Tendon Injuries / Q000150:complications / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014954:Wrist Injuries / Q000000981:diagnostic imaging*; D014955:Wrist Joint / Q000002:abnormalities* / Q000000981:diagnostic imaging*