title: Variation of the ulnar variance with powerful grip.
abstract: Causal relationships between ulnar variance and wrist disorders are known. Gripping and pronation cause proximal translation of the radius with respect to the ulna, leading to a statistically significant increase in ulnar variance. The purpose of this study was to investigate variation of the ulnar variance with powerful grip. A total of 41 male volunteers aged between 19 and 25 years (mean, 21.2+/-1.7 years) were studied. Posteroanterior X-ray films of all wrists were taken in the standardized position. After neutral posteroanterior X-ray films had been taken, subjects were asked to grip a Takei hand dynamometer with maximum force while repeated standardized posteroanterior X-ray films were obtained. Ulnar variance values were measured using the perpendicular method. Mean maximum grip force was 38.1 kg (range, 26.6-47.9 kg). Mean values of force-free (neutral) and forced ulnar variances were 0.06+/-0.21 mm and 1.87+/-0.23 mm, respectively. The difference in ulnar variance between the two groups was statistically significant ( P<0.001). The increase in ulnar variance with grip observed varied between 0.00 mm (minimum) and 3.97 mm (maximum), with a mean of 1.81 mm. Gaining an understanding of normal limits of ulnar variance modification with grip may be helpful in planning surgical treatment.
authors.affiliation: Department of Anatomy, Medical Faculty, Cumhuriyet University, 58140 Sivas, Turkey. msonmez@cumhuriyet.edu.tr
authors.forename: M
authors.initials: M
authors.lastname: Sönmez
authors.forename: U T
authors.initials: UT
authors.lastname: Turaçlar
authors.forename: F
authors.initials: F
authors.lastname: Taş
authors.forename: V
authors.initials: V
authors.lastname: Sabancioğullari
mesh_terms: D000328:Adult; D018737:Hand Strength; D006801:Humans; D008297:Male; D011859:Radiography; D014457:Ulna / Q000000981:diagnostic imaging* / Q000502:physiology; D014955:Wrist Joint / Q000000981:diagnostic imaging* / Q000502:physiology