title: A comparison of 3-D computed tomography versus 2-D radiography measurements of ulnar variance and ulnolunate distance during forearm rotation.
abstract: Positive ulnar variance is associated with ulnar impaction syndrome and ulnar variance is reported to increase with pronation. However, radiographic measurement can be affected markedly by the incident angle of the X-ray beam. We performed three-dimensional (3-D) computed tomography measurements of ulnar variance and ulnolunate distance during forearm rotation and compared these with plain radiographic measurements in 15 healthy wrists. From supination to pronation, ulnar variance increased in all cases on the radiographs; mean ulnar variance increased significantly and mean ulnolunate distance decreased significantly. However on 3-D imaging, ulna variance decreased in 12 cases on moving into pronation and increased in three cases; neither the mean ulnar variance nor mean ulnolunate distance changed significantly. Our results suggest that the forearm position in which ulnar variance increased varies among individuals. This may explain why some patients with ulnar impaction syndrome complain of wrist pain exacerbated by forearm supination. It also suggests that standard radiographic assessments of ulnar variance are unreliable.
authors: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors: Y
authors: Y
authors: Kawanishi
authors: Department of Physical Therapy, Osaka Yukioka College of Health Science, Osaka, Japan moritomo@ort.med.osaka-u.ac.jp.
authors: H
authors: H
authors: Moritomo
authors: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors: S
authors: S
authors: Omori
authors: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors: T
authors: T
authors: Kataoka
authors: Department of Orthopedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.
authors: T
authors: T
authors: Murase
authors: Department of Orthopedic Biomaterial Science, Osaka University Graduate School of Medicine, Suita, Japan.
authors: K
authors: K
authors: Sugamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D012667:Lunate Bone / Q000000981:diagnostic imaging* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011403:Pronation / Q000502:physiology; D011884:Radius / Q000000981:diagnostic imaging; D012399:Rotation; D013484:Supination / Q000502:physiology; D014057:Tomography, X-Ray Computed; D014457:Ulna / Q000000981:diagnostic imaging* / Q000502:physiology; D055815:Young Adult
keywords: Three-dimensional analysis; ulnar impaction syndrome; ulnar variance; ulnolunate distance