Distal Radioulnar Joint Orientation and Lunate Morphology as Protective Factors of Symptomatic Idiopathic Ulnar Impaction Syndrome in Ulnar-Positive Variant Patients

Abstract

Background

Ulnar-positive variance is widely recognized as a risk factor for idiopathic ulnar impaction syndrome (UIS). However, not all patients with ulnar-positive variance progress to symptomatic UIS. Other factors, such as the shape of the lunate or the distal radioulnar joint (DRUJ), may also play a role. This study aims to elucidate the relationship between the shape of the lunate and the structure of the DRUJ and idiopathic UIS.

Materials and Methods

A cohort of 40 cases diagnosed with idiopathic UIS (UIS group) and 87 control subjects with ulnar-positive variance but without symptoms were compared. Lunate shape was assessed by measuring the lunate type and radiolunate angle (RLA), whereas DRUJ morphology was evaluated using the sigmoid notch angle, DRUJ subluxation ratio, and DRUJ inclination. Independent t-tests were conducted to analyze differences in radiographic metrics between the two groups, and logistic regression analyses were used to examine risk factors for idiopathic UIS. Receiver operating characteristic curves were utilized to determine the cutoff values for statistically significant variables.

Results

Significant differences were observed between the two groups in terms of RLA, DRUJ subluxation ratio, and DRUJ inclination (p < 0.05). Logistic multiple regression analysis revealed a negative correlation between idiopathic UIS occurrence and both RLA (odds ratio [OR]: 0.92; 95% confidence interval [CI]: 0.87–0.96; p < 0.001) and the DRUJ subluxation ratio (OR: 0.01; 95% CI: 0–0.07; p = 0.002). Conversely, a positive correlation was found between UIS occurrence and DRUJ inclination (OR: 1.06; 95% CI: 1.01–1.12; p = 0.021).

Conclusion

In patients with ulnar-positive variance, the incidence of symptomatic UIS decreases when the lunate extends more relative to the radius and when the DRUJ subluxation ratio increases or DRUJ inclination decreases.

Level of Evidence

Level III, case–control study.

Keywords

ulnar impaction syndrome - ulnar-positive variance - lunate - distal radioulnar joint - protective factors

Publication History

Received: 13 May 2024

Accepted: 09 July 2024

Article published online:
25 July 2024

• References

• 1 Chun S, Palmer AK. The ulnar impaction syndrome: follow-up of ulnar shortening osteotomy. J Hand Surg Am 1993; 18 (01) 46-53
• 2 Palmer AK, Glisson RR, Werner FW. Relationship between ulnar variance and triangular fibrocartilage complex thickness. J Hand Surg Am 1984; 9 (05) 681-682
• 3 Friedman SL, Palmer AK, Short WH, Levinsohn EM, Halperin LS. The change in ulnar variance with grip. J Hand Surg Am 1993; 18 (04) 713-716
• 4 Tatebe M, Nakamura R, Horii E, Nakao E. Results of ulnar shortening osteotomy for ulnocarpal impaction syndrome in wrists with neutral or negative ulnar variance. J Hand Surg Am 2005; 30 (02) 129-132
• 5 Palmer AK, Glisson RR, Werner FW. Ulnar variance determination. J Hand Surg Am 1982; 7 (04) 376-379
• 6 Tomaino MM. The importance of the pronated grip x-ray view in evaluating ulnar variance. J Hand Surg Am 2000; 25 (02) 352-357
• 7 Park JH, Jang WY, Kwak DH, Park JW. Lunate morphology as a risk factor of idiopathic ulnar impaction syndrome. Bone Joint J 2017; 99-B (11) 1508-1514
• 8 Viegas SF, Patterson RM, Hokanson JA, Davis J. Wrist anatomy: incidence, distribution, and correlation of anatomic variations, tears, and arthrosis. J Hand Surg Am 1993; 18 (03) 463-475
• 9 Bain GI, Clitherow HD, Millar S. et al. The effect of lunate morphology on the 3-dimensional kinematics of the carpus. J Hand Surg Am 2015; 40 (01) 81-9 e1
• 10 Nakamura K, Beppu M, Patterson RM, Hanson CA, Hume PJ, Viegas SF. Motion analysis in two dimensions of radial-ulnar deviation of type I versus type II lunates. J Hand Surg Am 2000; 25 (05) 877-888
• 11 Mauler F, Beaulieu JY. Morphological associations between the distal radioulnar joint and the lunate. J Wrist Surg 2018; 7 (02) 148-155
• 12 Nakamura R, Horii E, Imaeda T, Nakao E, Kato H, Watanabe K. The ulnocarpal stress test in the diagnosis of ulnar-sided wrist pain. J Hand Surg Am 1997; 22 (06) 719-723
• 13 Doherty C, Gan BS, Grewal R. Ulnar shortening osteotomy for ulnar impaction syndrome. J Wrist Surg 2014; 3 (02) 85-90
• 14 Palmer AK, Werner FW. Biomechanics of the distal radioulnar joint. Clin Orthop Relat Res 1984; (187) 26-35
• 15 Viegas SF, Wagner K, Patterson R, Peterson P. Medial (hamate) facet of the lunate. J Hand Surg Am 1990; 15 (04) 564-571
• 16 Park JH, Kang TW, Choi J, Kim SG, Ahn KS, Park JW. Radiographic prediction of lunate morphology in Asians using plain radiographic and capitate-triquetrum distance analyses: reliability and compatibility with magnetic resonance arthrography (MRA) findings. BMC Musculoskelet Disord 2019; 20 (01) 128
• 17 Yang Z, Mann FA, Gilula LA, Haerr C, Larsen CF. Scaphopisocapitate alignment: criterion to establish a neutral lateral view of the wrist. Radiology 1997; 205 (03) 865-869
• 18 Mane SA, Saeki Y, Sakamoto S. Distal radioulnar joint translation evaluated by maximum intensity projection images of computed tomography. J Hand Surg Eur Vol 2024; 49 (04) 501-503
• 19 Tolat AR, Sanderson PL, De Smet L, Stanley JK. The gymnast's wrist: acquired positive ulnar variance following chronic epiphyseal injury. J Hand Surg Am 1992; 17 (06) 678-681
• 20 Nakamura R, Tanaka Y, Imaeda T, Miura T. The influence of age and sex on ulnar variance. J Hand Surg Am 1991; 16 (01) 84-88
• 21 Gong HS, Jeon SH, Baek GH. Ulnar-sided wrist pain after four-corner fusion in a previously-asymptomatic ulnar positive wrist: a case report. Hand Surg 2009; 14 (01) 49-51
• 22 Yan RC, Jin BT. In vivo gliding and contact characteristics of the sigmoid notch and the ulna in forearm rotation. J Hand Surg Am 2013; 38 (08) 1513-1519