Four-Dimensional CT Analysis of Dorsal Intercalated Segment Instability in patients with Suspected Scapholunate Instability

Abstract

Background In this study we sought to evaluate the contribution of dynamic four-dimensional computed tomography (4DCT) relative to the standard imaging work-up for the identification of the dorsal intercalated segment instability (DISI) in patients with suspected chronic scapholunate instability (SLI). Methods Forty patients (22 men, 18 women; mean age 46.5 ± 13.1 years) with suspected SLI were evaluated prospectively with radiographs, arthrography, and 4DCT. Based on radiographs and CT arthrography, three groups were defined: positive SLI (n = 16), negative SLI (n = 19), and questionable SLI (n = 5). Two independent readers used 4DCT to evaluate the lunocapitate angle (LCA) (mean, max, coefficient of variation [CV], and range values) during radioulnar deviation. Results The interobserver variability of the 4DCT variables was deemed excellent (intraclass correlation coefficient = 0.79 to 0.96). Between the three groups, there was no identifiable difference for the LCAmean. The LCAmax values were lower in the positive SLI group (88 degrees) than the negative SLI group (102 degrees). The positive SLI group had significantly lower LCAcv (7% vs. 12%, p = 0.02) and LCArange (18 vs. 27 degrees, p = 0.01) values than the negative SLI group. The difference in all the LCA parameters between the positive SLI group and the questionable SLI group was not statistically significant. When comparing the negative SLI and questionable SLI groups, the LCAcv (p = 0.03) and LCArange (p = 0.02) values were also significantly different. The best differentiation between patients with and without SLI was obtained with a LCAcv and LCArange threshold values of 9% (specificity of 63% and sensitivity of 62%) and 20 degrees (specificity of 71% and sensitivity of 63%), respectively. Conclusion In this study, 4DCT appeared as a quantitative and reproducible relevant tool for the evaluation of DISI deformity in cases of SLI, including for patients presenting with questionable initial radiography findings. Level of evidence This is a Level III study.

Evaluation of Scapholunate Injury and Repair with Dynamic (4D) CT: A Preliminary Report of Two Cases

“…13 4DCT or quasi-dynamic CT has been used to assess SL biomechanics in uninjured participants, those with SL injuries preoperatively, and in cadaveric studies of SL biomechanics. 24,[27][28][29][30][31][32][33][34]51 This work builds on previous studies to demonstrate the applicability of 4DCT as a diagnostic and evaluation tool to reveal arthrokinematic changes at the radioscaphoid joint and SL intervals. While studies have evaluated the diagnostic utility of 4DCT, 31,52 this work highlights its role in postsurgical evaluation, especially in discerning subtle arthrokinematic changes.…”

“…Since its earliest proof-of-concept applications, 4DCT has been applied to assess SL biomechanics in cadaveric models, 25,33,[57][58][59] joint-level arthrokinematics, 27,28,30,[60][61][62][63] and as a preclinical diagnostic tool. 24,28,29,32,60,64 A narrative review summarized the state and previous applications of 4DCT imaging (see White et al 52 ). 4DCT represents a promising technology to detect wrist pathology and evaluate outcomes longitudinally.…”

“…Over the past decade, four-dimensional CT (4DCT)—standard 3DCT captured over motion cycles—has been introduced to capture CT volumes at evenly spaced time points during wrist motion with high spatial and temporal resolution. 24 25 26 27 28 29 30 31 32 33 34 35 This may allow identification of early ligamentous injuries and influence treatment strategy. 24…”

“…23 Over the past decade, four-dimensional CT (4DCT)-standard 3DCT captured over motion cycles-has been introduced to capture CT volumes at evenly spaced time points during wrist motion with high spatial and temporal resolution. [24][25][26][27][28][29][30][31][32][33][34][35] This may allow identification of early ligamentous injuries and influence treatment strategy. 24 We present the emerging use of 4DCT in a case series of two patients with surgically treated unilateral SLIL injuries to evaluate its utility in diagnosis and interpret changes in arthrokinematics, specifically interosseous proximities, following injury and 1-year postoperatively.…”

Scaphoid kinematics in scapholunate instability: a dynamic CT study

“…The radiation dose for a 4D-CT scan is 0.231 mSv [ 18 ], which is considered low-dose radiation. Recent 4D-CT publications have been directed at improving the diagnostic accuracy of dynamic SL instability [ 20 – 22 ]. However, there have been no reports on the 6 degrees of freedom kinematics of the scaphoid in SLI in an in vivo study.…”