What Is the Diagnostic Accuracy of Flat-panel Cone-beam CT Arthrography for Diagnosis of Scapholunate Ligament Tears?

BACKGROUND: Cone beam CT (CBCT) is a widely available technique with possible indications in carpal ligament injuries. The accuracy of CBCT arthrography in diagnosing traumatic tears of the scapholunate ligament has not been reported. QUESTIONS/PURPOSES: (1) What is the diagnostic accuracy of CBCT and how does it relate to the accuracy of multislice CT arthrography and conventional arthrography in diagnosing scapholunate ligament tears? (2) What is the estimated magnitude of skin radiation doses of each method? METHODS: This secondary analysis of a previous prospective study included 71 men and women with suspected scapholunate ligament tears and indications for arthroscopy. Preoperative imaging was conventional arthrography and either MSCT arthrography for the first half of patients to be included (n = 36) or flat-panel CBCT arthrography for the remaining patients (n = 35). Index tests identified therapy-relevant SLL tears with dorsal or complete SLL ruptures, and these tears were compared with relevant SLL tears which were determined through arthroscopy as Geissler Stadium III and IV by probing the instable SL joint with a microhook or arthroscope. These injuries were treated by open ligament repair and Kirschner wire fixation. Accuracy values and 95% confidence intervals were calculated. Additional estimates of the radiation skin doses of each CBCT exam and two MSCT protocols were subsequently calculated using dose area products, dose length products, and CT dose indices. RESULTS: The diagnostic accuracy was high for all imaging methods. 95% CIs were broadly overlapping and therefore did not indicate differences between the diagnostic groups: Sensitivity of CBCT arthrography was 100% (95% CI 77 to 100), specificity was 95% (95% CI 76 to 99.9), positive predictive value was 93% (95% CI 68 to 99.8), and negative predictive value was 100% (95% CI 83 to 100). For MSCT arthrography, the sensitivity was 92% (95% CI 64 to 99.8), specificity was 96% (95% CI 78 to 99.9), positive predictive value was 92% (95% CI 64 to 99.8), and negative predictive value was 96% (95% CI 78 to 99.9). For conventional arthrography, the sensitivity was comparably high: 96% (95% CI 81 to 99.9). Specificity was (81% [95% CI 67 to 92]); the positive predictive value was 77% (95% CI 59 to 89) and negative predictive value was 97% (95% CI 86 to 99.9). Estimated mean (range) radiation skin doses were reported in a descriptive fashion and were 12.9 mSv (4.5 to 24.9) for conventional arthrography, and 3.2 mSv (2.0 to 4.8) for CBCT arthrography. Estimated radiation skin doses were 0.2 mSv and 12 mSv for MSCT arthrography, depending on the protocol. CONCLUSION: Flat-panel CBCT arthrography can be recommended as an accurate technique to diagnose scapholunate ligament injuries after wrist trauma. Estimated skin doses are low for CBCT arthrography and adapted MSCT arthrography protocols. LEVEL OF EVIDENCE: Level III, diagnostic study.

Single versus dual Kirschner wires for closed reduction and intramedullary nailing of displaced fractures of the fifth metacarpal neck (1-2 KiWi): a randomized controlled trial.

AIMS: The aim of this study was to investigate whether clinical and radiological outcomes after intramedullary nailing of displaced fractures of the fifth metacarpal neck using a single thick Kirschner wire (K-wire) are noninferior to those of technically more demanding fixation with two thinner dual wires. PATIENTS AND METHODS: This was a multicentre, parallel group, randomized controlled noninferiority trial conducted at 12 tertiary trauma centres in Germany. A total of 290 patients with acute displaced fractures of the fifth metacarpal neck were randomized to either intramedullary single-wire (n = 146) or dual-wire fixation (n = 144). The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire six months after surgery, with a third of the minimal clinically important difference (MCID) used as the noninferiority threshold. Secondary outcomes were pain, health-related quality of life (EuroQol five-dimensional questionnaire (EQ-5D)), radiological measures, functional deficits, and complications. RESULTS: Overall, 151/290 of patients (52%) completed the six months of follow-up, leaving 83 patients in the single-wire group and 68 patients in the dual-wire group. In the modified intention-to-treat analysis set, mean DASH scores six months after surgery were 3.8 (sd 7.0) and 4.4 (sd 9.4), respectively. With multiple imputation (n = 288), mean DASH scores were estimated at 6.3 (sd 8.7) and 7.0 (sd 10.0). Upper (1 - 2α)) confidence limits consistently remained below the noninferiority margin of 3.0 points in the DASH instrument. While there was a statistically nonsignificant trend towards a higher rate of shortening and rotational malalignment in the single wire group, no statistically significant differences were observed across groups in any secondary outcome measure. CONCLUSION: A single thick K-wire is sufficient for intramedullary fixation of acute displaced subcapital fractures of the fifth metacarpal neck. The less technically demanding single-wire technique produces noninferior clinical and radiological outcomes compared with the dual-wire approach. Cite this article: Bone Joint J 2019;101-B:1263-1271.