Morphology at the Distal Radioulnar Joint: Identifying the Prevalence of Reverse Obliquity

Abstract

<jats:title>Abstract</jats:title><jats:p> Background Recent advances in the understanding of ulnar-sided wrist pathologies such as ulnar abutment syndrome (UAS) have brought increased attention to the anatomy of the distal radioulnar joint (DRUJ). Previous work established three anatomical variants of the sigmoid notch (parallel, oblique, and reverse oblique). The reverse oblique DRUJ poses theoretical risk of increased contact forces following ulnar shortening osteotomy, a common method of treating UAS.</jats:p><jats:p> Purpose As prevalence of reverse oblique morphology has been under-reported, this study aims to better define the prevalence of reverse oblique morphology in the adult population.</jats:p><jats:p> Methods Institutional Review Board-approved review of 1,000 radiographs over a 2-year period was performed. Demographic data and radiographic measurements were recorded (ulnar variance, notch inclination, and presence of arthritis). Correlation tests, a test of proportions, a t-test, and linear and logic regression tests were used to examine associations between ulnar variance, sigmoid inclination, sex, age, and presence of arthritis.</jats:p><jats:p> Results One thousand radiographs were analyzed revealing prevalence rates of: parallel—68%, oblique—26%, and reverse oblique—6%. Females were significantly more likely to have reverse inclination. No significant correlation was noted for morphology by age. Ulna positive variance was negatively correlated with reverse inclination. DRUJ arthritis was noted in 14% of patients. Higher sigmoid inclination was associated with higher odds of presence of arthritis, adjusting for sex and age. Higher incidence of arthritis was noted among patients with the oblique (20.8%) or reverse oblique (24.6%) compared with parallel (10.5%) morphology.</jats:p><jats:p> Conclusion This series of 1,000 radiographs demonstrates a 6% overall prevalence of reverse obliquity. This large dataset allows for better quantification of the prevalence of DRUJ morphologies and determination of correlations that have clinical implications for patients with ulnar-sided wrist pathology.</jats:p><jats:p> Level of Evidence This is a Level IV study.</jats:p>

Ulnar Bowing and Distal Radioulnar Joint Anatomy: A Three-Dimensional, In Situ Clinical Assessment

“…This has been highlighted in previous investigations with the prevalence of reverse obliquity morphology at the DRUJ. 2 Authors have suggested caution in using ulnar shortening osteotomy in this morphology. Moreover, our study confirms that sagittal alignment and translation at the DRUJ articulation are directly related to ulna bowing at the distal ulna.…”

“…Conditions and injury to the components of this intricate joint can be devastating to patients. 1 , 2 , 3 , 4…”

Risk Factors for the Incidence of the Volar Lunate Facet Fragments in Distal Radius Fractures

“…They also concluded that reverse oblique morphology correlated with ulnar-sided wrist pathology including DRUJ arthritis. 17 Kumar et al analyzed the volar surface of the uninjured distal radius using CT scans, and they showed that considerable variation occurs in volar surface curvature morphology. 18 In the current study, a smaller SNA, larger VT, and smaller LFCR were shown to be the possible risk factors for VLF occurrence.…”

“…With a larger SNA in the AP radiograph, axial load from the lunate should be applied toward the radial bone axis. However, with a smaller SNA (reverse oblique type 17 ), it would be applied in the ulnar direction, which can result in fracture of the distal volar lip. A larger VT and smaller LFCR in the lateral radiograph means that the deep lunate facet is tilting in the volar direction.…”

Outcome of Preoperative Asymptomatic or Minimally Symptomatic DRUJ Arthritis after Total Wrist Arthrodesis: A Single-Institution Case Series

“…Based on prior literature, there is a 14% incidence of asymptomatic radiographic DRUJ arthritis and 8% incidence of symptomatic DRUJ arthritis in patients who undergo TWA. 20 31 Using these two numbers, it would require 229 patients to reach 80% power of detecting symptomatic DRUJ arthritis requiring surgery after TWA. Additionally, although the present study reported adequate mid-term follow-up compared with other similar studies, longer follow-up may have identified more patients who experienced substantial DRUJ symptoms that would benefit from surgery.…”