Assessment of Scapholunate Instability on 4D CT Scans in Patients with Inconclusive Conventional Images.

Background Initial imaging work-up using radiography and CT arthrography sometimes can be insufficient to identify a scapholunate (SL) instability (SLI) in patients suspected of having SL ligament tears. Purpose To determine the diagnostic performance of four-dimensional (4D) CT in the identification of SLI and apply the findings to patients suspected of having SLI and with inconclusive findings on radiographs and CT arthrograms. Materials and Methods This prospective single-center study enrolled participants suspected of having SLI (recent trauma, dorsal pain, positive Watson test results, decreased grip strength) between March 2015 and March 2020. Participants with wrist fractures, substantial joint stiffness, or history of wrist surgery were excluded. Each participant underwent radiography, CT arthrography, and 4D CT on the same day. Participants were divided into three groups: those with no SLI, those with SLI, and those with inconclusive results. SL gap and radioscaphoid and lunocapitate angle were measured using semiautomatic quantitative analysis of 4D CT images by two independent readers. Receiver operating characteristic curves were used to evaluate the diagnostic performance of 4D CT. Thresholds were determined with the Youden index and were applied to the inconclusive group. Results Of the 150 included participants (mean age, 41 years ± 14 [SD]; 102 male, 48 female), there were 63 with no SLI, 48 with SLI, and 39 with inconclusive results. The maximum value and range of SL gap measurements on 4D CT scans showed high sensitivity (83% [40 of 48] and 90% [43 of 48], respectively) and high specificity (95% [59 of 62] and 81% [50 of 62], respectively) in the identification of SLI. At least one of these parameters was abnormal on 4D CT scans in 17 of 39 (44%) participants in the inconclusive group, and 10 of 17 (59%) participants had confirmed SLI. In the 22 participants in the inconclusive group with no indication of SLI at 4D CT, follow-up showed no evidence of SLI in 10 (45%) and enabled confirmation of SLI via arthroscopy in three (14%). Conclusion Scapholunate gap measurements on kinematic 4D CT scans enabled correct identification of SLI in 59% of participants with inconclusive results on conventional images. ClinicalTrials.gov registration no. NCT02401568 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Demehri and Ibad in this issue.

Correlation Between Dynamic 4-Dimensional Computed Tomography Data and Arthroscopic Testing of Scapholunate Instability: A Preliminary Study.

PURPOSE: The aim of this study was to test the validity and reliability of the assessments of scapholunate (SL) instability status on 4-dimensional (4D) computed tomography (CT) using wrist arthroscopy as a reference standard. METHODS: Thirty-three patients (16 men, 17 women; mean age, 48 ± 13 years) with suspected SL instability were evaluated prospectively with 4D-CT and wrist arthroscopy. Based on the arthroscopic testing of SL joint, 2 groups were defined: group 1 (n = 8) consisted of patients who had no, or slight, SL malalignment in the midcarpal space and group 2 (n = 25) consisted of patients who had moderate or severe SL malalignment. Two independent readers, who did not know the arthroscopic findings, used 4D-CT to evaluate the SL gap, lunocapitate angle (LCA), and radioscaphoid angle (mean and range values) during radioulnar deviation. RESULTS: The interobserver reliability was deemed good or excellent for most of the 4D-CT variables, except for the LCA range (moderate) and SL gap range (poor). For both readers, the SL gap mean, maximum, and minimum values were significantly higher (+67%, +78%, and +39%, respectively) and the LCA mean was significantly lower (-17%) in group 2 than in group 1. The radioscaphoid angle range values were lower (-34%) and the radioscaphoid angle mean values slightly higher (+4%) in group 2, but there was no significant difference between the 2 groups. The SL gap range values were also higher (+86% for R1 and +40% for R2) and the LCA range values also lower (-50% for R1 and -31% for R2) in group 2. CONCLUSIONS: Quantitative 4D-CT data corresponded well with the arthroscopic dynamic analysis of the SL joint in patients with suspected chronic SL instability. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

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

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 LCA mean . The LCA max values were lower in the positive SLI group (88 degrees) than the negative SLI group (102 degrees). The positive SLI group had significantly lower LCA cv (7% vs. 12%, p = 0.02) and LCA range (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 LCA cv ( p = 0.03) and LCA range ( p = 0.02) values were also significantly different. The best differentiation between patients with and without SLI was obtained with a LCA cv and LCA range 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 Dorsal Scaphoid Displacement Using Posterior Radioscaphoid Angle in Patients With Suspected Scapholunate Instability: A Preliminary Study.

PURPOSE: To assess the validity and reliability of the posterior radioscaphoid angle (PRSA), an indicator of dorsal displacement of the scaphoid, in distinguishing wrists with and without chronic scapholunate instability (SLI). METHODS: We prospectively evaluated 40 patients (22 men and 18 women; mean age, 46 ± 13 years) with suspected SLI with radiographs and computed tomography arthrography. Based on these data, 3 groups were defined: positive SLI (n = 16), negative SLI (n = 19), and questionable SLI (n = 5). An independent reader measured the PRSA on sagittal computed tomography images using the same procedure. RESULTS: The PRSA median values were significantly lower in the negative SLI group (98°) compared with the positive SLI (110°) and questionable SLI (111°) groups. The difference between the positive SLI and questionable SLI groups was not significant. The best differentiation between patients with and without SLI was obtained with a PRSA threshold value of 103° (specificity of 86% and sensitivity of 79%). CONCLUSIONS: In this preliminary study, PRSA analysis offers a quantitative tool for the evaluation of dorsal scaphoid displacement in cases of SLI, including for patients presenting with questionable initial radiography findings. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Assessment of scapholunate instability with dynamic computed tomography.

We performed a prospective study to evaluate the values of dynamic four-dimensional computed tomography in assessing suspected chronic scapholunate instability. Forty patients were evaluated with radiographs, arthrography, and four-dimensional computed tomography. On plain radiographs and computed tomography, we found 16 patients with definite scapholunate instability, five with questionable scapholunate instability, and 19 with absence of scapholunate instability. We used four-dimensional computed tomography to evaluate the size of the scapholunate gap during radioulnar deviation. The mean and maximal values of the gap size were lowest in the patients with absence of scapholunate instability and highest in those with definite scapholunate instability. When comparing the scapholunate gap sizes of the patients with absent and questionable scapholunate instability, the range of the gap sizes was significantly higher in the patients with questionable scapholunate instability. We conclude that four-dimensional computed tomography aids assessment of chronic scapholunate instability, which allows the differentiation between patients without and those with definite or questionable scapholunate instability. Level of evidence: II.

Avascular necrosis of the capitate: case series of five patients and review of literature.

Avascular necrosis of the capitate is a rare disorder of unknown aetiology that causes wrist pain and limits function. From 2009 to 2017, we performed scaphocapitolunate arthrodesis on five patients (one male, four females) with a mean age of 35 years (range 30-37) who had idiopathic avascular necrosis of the capitate. All patients had scaphocapitate and lunocapitate arthritis confirmed by arthroscopy. The mean follow-up was 5 years (range 1-9). At the latest follow-up, the mean wrist flexion-extension was 95° (versus 105° before surgery). Grip strength was 90% relative to the contralateral side. Functional scores were all significantly improved following treatment. Radiologically, fusion was achieved in all cases and there was no displacement or fracture of the bone fixation material. None of the patients had signs of midcarpal collapse or narrowing of the radiocarpal joint space. We conclude that scaphocapitolunate arthrodesis is an acceptable treatment for avascular necrosis of the capitate with midcarpal chondral lesions. It provides adequate pain relief and improves grip strength during medium-term follow-up. Level of evidence: IV.