Acute, isolated and unstable syndesmotic injuries are frequently associated with intra-articular pathologies

PURPOSE Although simultaneous arthroscopy for the surgical treatment of acute isolated, unstable syndesmotic injuries has been recommended, little knowledge is present about the actual frequency of intra-articular pathologies for this injury. The aim of this study was to investigate the frequency and severity of intra-articular pathologies detected during arthroscopy and their subsequent treatment in acute isolated, unstable syndesmotic injuries. METHODS A retrospective chart review of patients treated by arthroscopic-assisted stabilization for acute isolated, syndesmotic instability was performed. The primary outcome parameter was the frequency of intra-articular pathologies. Secondary outcome parameters were the type of syndesmotic lesion (ligamentous/bony), severity of chondral lesions, MRI findings, treatment details, complications and the identification of factors associated with intra-articular pathologies. RESULTS Twenty-seven patients, 19% female, with a mean age of 37 ± 12~years met the inclusion criteria. 70% suffered isolated ligamentous injuries, the remaining suffered avulsion fractures of the syndesmosis. Chondral lesions occurred in 48% (ICRS grade II: 33%; ICRS grade IV 15%) and intra-articular loose bodies in 11% of patients. Overall, arthroscopy revealed intra-articular pathologies necessitating further treatment in 19% of patients. Neither the type of syndesmotic injury (bony vs. ligamentous; ns) nor the degree of ligamentous instability (West Point IIB vs. III; ns) had a significant influence on the occurrence of chondral lesions. One complication (SSI) occurred. Pre-operative MRI revealed a sensitivity/specificity of 100/79% for chondral lesions and 50/93% for loose bodies. CONCLUSION Intra-articular pathologies in acute isolated, unstable syndesmotic injuries occur in up to 50% of patients, 19% necessitated additional treatment. Simultaneous arthroscopy, independent of the pre-operative MRI findings, appears reasonable in highly active patients. LEVEL OF EVIDENCE Level III

Perspectives on the revised Ghent criteria for the diagnosis of Marfan syndrome

Three international nosologies have been proposed for the diagnosis of Marfan syndrome (MFS): the Berlin nosology in 1988; the Ghent nosology in 1996 (Ghent-1); and the revised Ghent nosology in 2010 (Ghent-2). We reviewed the literature and discussed the challenges and concepts of diagnosing MFS in adults. Ghent-1 proposed more stringent clinical criteria, which led to the confirmation of MFS in only 32%-53% of patients formerly diagnosed with MFS according to the Berlin nosology. Conversely, both the Ghent-1 and Ghent-2 nosologies diagnosed MFS, and both yielded similar frequencies of MFS in persons with a causative FBN1 mutation (90% for Ghent-1 versus 92% for Ghent-2) and in persons not having a causative FBN1 mutation (15% versus 13%). Quality criteria for diagnostic methods include objectivity, reliability, and validity. However, the nosology-based diagnosis of MFS lacks a diagnostic reference standard and, hence, quality criteria such as sensitivity, specificity, or accuracy cannot be assessed. Medical utility of diagnosis implies congruency with the historical criteria of MFS, as well as with information about the etiology, pathogenesis, diagnostic triggers, prognostic triggers, and potential complications of MFS. In addition, social and psychological utilities of diagnostic criteria include acceptance by patients, patient organizations, clinicians and scientists, practicability, costs, and the reduction of anxiety. Since the utility of a diagnosis or exclusion of MFS is context-dependent, prioritization of utilities is a strategic decision in the process of nosology development. Screening tests for MFS should be used to identify persons with MFS. To confirm the diagnosis of MFS, Ghent-1 and Ghent-2 perform similarly, but Ghent-2 is easier to use. To maximize the utility of the diagnostic criteria of MFS, a fair and transparent process of nosology development is essential

Clinical and radiological results after surgical treatment of patella fractures

Die Durchblutung der Patella beruht auf 2 Zuflüssen. Einerseits Gefäße, welche im mittleren Drittel von ventral über Foramina in die Patella eintreten und außerdem Gefäße, welche am distalen Pol zwischen dem Lig. Patellae und der Gelenkfläche in die Patella eintreten und nach proximal verlaufen. Patellafrakturen können in Längs-, Quer- und Trümmerfrakturen unterteilt werden. Bei Frakturen der Patella kann im Bereich des proximalen Pols eine arterielle Minderversorgung resultieren, wohingegen der distale Pol doppelt versorgt ist und nicht affektiert erscheint. Die arterielle Hypoperfusion kann zu lokalisierten Osteonekrosen führen. Diese lokalen osteonekrotischen Areale können sich radiographisch als hyperdense Areale manifestieren. Im Rahmen dieser Studie sollte das klinische und radiologische Ergebnis nach operativ versorgter Patellafraktur untersucht werden. Dabei wurden 100 Patienten untersucht, die im Zeitraum von 1998 – 2008 operativ versorgt wurden. Davon konnten 60 Patienten im Mittel nach 60.61 ( ± 33.88) Monaten mit einem durchschnittlichen Alter 45.48 ( ± 18.51) Jahren im Rahmen eines Follow-Ups untersucht werden. Dabei wurden mehrere klinische Scores, die Patientenzufriedenheit und die visuelle Analogskala Schmerz erhoben und die vorher angefertigten radiologischen Aufnahmen ausgewertet. Diese wurden auf eventuelle Stufenbildungen, Defekte oder hyperdense Areale hin untersucht. Es zeigte sich bei 9 Patienten (9%) ein hyperdenses Areal im Bereich des proximalen Pols welches durchschnittlich 1 – 2 Monate nach der operativen Versorgung nachgewiesen wurde. Bei 7 Patienten war dieses Areal nach 6 Monaten nicht mehr nachweisbar. Bei 2 Patienten mit bestehenden hyperdensen Arealen konnten diese im Verlauf mittels MRT respektive einer histologischen Untersuchung gesichert werden. Es zeigte sich insgesamt kein signifikanter Unterschied zwischen Patienten ohne radiologische Auffälligkeiten und mit hyperdensen Arealen. Jedoch wurden für die Gruppe mit hyperdensen Arealen im Vergleich tendentiell schlechtere Werte notiert. Radiologisch hyperdense Areale im Bereich des proximalen Pols bei Zustand nach operativer Versorgung einer Patellafraktur können eine Osteonekrose repräsentieren. Eine frühere operative Versorgung bzw. schonendere Operationstechniken könnten die Entstehung von osteonekrotischen Arealen verhindern. Zur Bestätigung dieser Hypothese sind weitere Untersuchungen notwendig

Structures of \u3cem\u3ePseudomonas aeruginosa\u3c/em\u3e LpxA Reveal the Basis for Its Substrate Selectivity

In Gram-negative bacteria, the first step of lipid A biosynthesis is catalyzed by UDP-N-acetylglucosamine acyltransferase (LpxA) through the transfer of a R-3-hydroxyacyl chain from the acyl carrier protein (ACP) to the 3-hydroxyl group of UDP-GlcNAc. Previous studies suggest that LpxA is a critical determinant of the acyl chain length found in lipid A, which varies among species of bacteria. In Escherichia coli and Leptospira interrogans, LpxA prefers to incorporate longer R-3-hydroxyacyl chains (C14 and C12, respectively), whereas in Pseudomonas aeruginosa, the enzyme is selective for R-3-hydroxydecanoyl, a 10-hydrocarbon long acyl chain. We now report three P. aeruginosa LpxA crystal structures: apo protein, substrate complex with UDP-GlcNAc, and product complex with UDP-3-O-(R-3-hydroxydecanoyl)-GlcNAc. A comparison between the apo form and complexes identifies key residues that position UDP-GlcNAc appropriately for catalysis and supports the role of catalytic His121 in activating the UDP-GlcNAc 3-hydroxyl group for nucleophilic attack during the reaction. The product-complex structure, for the first time, offers structural insights into how Met169 serves to constrain the length of the acyl chain and thus functions as the so-called hydrocarbon ruler. Furthermore, compared with ortholog LpxA structures, the purported oxyanion hole, formed by the backbone amide group of Gly139, displays a different conformation in P. aeruginosa LpxA, which suggests flexibility of this structural feature important for catalysis and the potential need for substrate-induced conformational change in catalysis. Taken together, the three structures provide valuable insights into P. aeruginosa LpxA catalysis and substrate specificity as well as templates for future inhibitor discovery

Prediction of Meniscal and Ligamentous Injuries in Lateral Tibial Plateau Fractures Based on Measurements of Lateral Plateau Widening on Multidetector Computed Tomography Scans

Background. The influence of increasing lateral plateau widening on the frequency of meniscal and ligamentous lesions in lateral tibial plateau fractures has been examined in very few studies using plain radiographs. Because the amount of this parameter cannot be measured accurately on plain radiographs, the purpose of this survey was to look for a possible correlation between the extent of lateral plateau widening, as measured on multidetector CT (MDCT) scans, and different soft-tissue injuries determined from magnetic resonance imaging (MRI). Materials and Methods. 55 patients with a lateral tibial plateau fracture were included in this retrospective case series. Patient age averaged 52.6 years (SD = 18.0). The degree of lateral plateau widening was measured on CT images. MRIs were screened for meniscal and ligamentous injuries. Results. We found a significant effect of increasing lateral plateau widening on the incidence of lateral meniscus lesions (P = 0.021), lateral collateral ligament tears (P = 0.047), and the overall quantity of meniscal and ligamentous lesions (P = 0.001). Discussion. MRIs are not widely used as a diagnostic tool in lateral plateau fractures of the tibia. Reasons might be the costs and the fact that it is a time-consuming examination. The results of this study may help to estimate the probability of specific soft-tissue lesions in lateral tibial plateau fractures based on measurements of lateral plateau widening on MDCT scans, and they may guide the decision for additional MRI and/or arthroscopically assisted repair

Inter- and Intraobserver reproducibility of T2 relaxation times of the discus interpubicus: A feasibility study at 3 Tesla.

OBJECTIVE:To quantify standard values of the discus interpubicus in healthy subjects and to determine reliability and repeatability using T2 relaxation time measurements at 3T. METHODS:20 asymptomatic participants (10 male, 10 female; mean age: 27.3 years ±4.1, BMI: 22.2 ±1.8) underwent a 3T Magnetic Resonance Imaging (MRI) of the pelvic region in a supine position. We included sagittal and para-axial T2w sequences centred over the pubic symphysis in order to identify the complete discus interpubicus. For quantitative analysis, a multi-echo Turbo Spin Echo (TSE) sequence (including 12 echo times between 6.4 and 76.8 ms) was acquired and analysed by using an in-house developed quantification plugin tool (qMapIt) extending ImageJ. Two readers in consensus defined three central slices of the pubic symphysis with the greatest length. For each slice, both readers separately placed three regions-of-interest (ROI) covering the whole discus interpubicus. Both readers repeated the ROI placements in identical fashion after a four-week interval on the original MRI images. Statistical analysis included intraclass correlation coefficient (ICC), nonparametric Wilcoxon test, Fisher exact test and mean relaxation time in ms and 95% confidence intervals. RESULTS:T2 relaxation time analysis was performed for all 20 participants. In total, a mean relaxation time of all analysed segments for both observers was 48.6 (±6.3 ms), with a mean relaxation time for observer 1 of 48.7 (±6.0 ms) and for observer 2 of 48.5 ms (±6.6ms). The calculated ICC comparing inter- and intrarater reproducibility was excellent in all segments (≥0.75). CONCLUSION:T2 mapping of the discus interpubicus demonstrates good inter- and intrarater repeatability as well as reliability. Mean relaxation times were calculated with 48.6ms in healthy volunteers

CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP.

PURPOSE:To assess image quality of CT pulmonary angiography (CTPA) at reduced radiation exposure (RD-CTPA) and contrast medium (CM) volume using two different iterative reconstruction (IR) algorithms (iDose4 and iterative model reconstruction (IMR)) in comparison to filtered back projection (FBP). MATERIALS AND METHODS:52 patients (body weight < 100 kg, mean BMI: 23.9) with suspected pulmonary embolism (PE) underwent RD-CTPA (tube voltage: 80 kV; mean CTDIvol: 1.9 mGy) using 40 ml CM. Data were reconstructed using FBP and two different IR algorithms (iDose4 and IMR). Subjective and objective image quality and conspicuity of PE were assessed in central, segmental, and subsegmental arteries. RESULTS:Noise reduction of 55% was achieved with iDose4 and of 85% with IMR compared to FBP. Contrast-to-noise ratio significantly increased with iDose4 and IMR compared to FBP (p<0.05). Subjective image quality was rated significantly higher at IMR reconstructions in comparison to iDose4 and FBP. Conspicuity of central and segmental PE significantly improved with the use of IMR. In subsegmental arteries, iDose4 was superior to IMR. CONCLUSIONS:CTPA at reduced radiation exposure and contrast medium volume is feasible with the use of IMR, which provides improved image quality and conspicuity of pulmonary embolism in central and segmental arteries

Non-contrast MR angiography at 1.5 Tesla for aortic monitoring in Marfan patients after aortic root surgery

Background: Contrast-enhanced cardiovascular magnetic resonance angiography (CE-CMRA) is the established imaging modality for patients with Marfan syndrome requiring life-long annual aortic imaging before and after aortic root replacement. Contrast-free CMRA techniques avoiding side-effects of contrast media are highly desirable for serial imaging but have not been evaluated in the postoperative setup of Marfan patients. The purpose of this study was to assess the feasibility of non-contrast balanced steady-state free precession (bSSFP) magnetic resonance imaging for aortic monitoring of postoperative patients with Marfan syndrome. Methods: Sixty-four adult Marfan patients after aortic root replacement were prospectively included. Fourteen patients (22%) had a residual aortic dissection after surgical treatment of type A dissection. bSSFP imaging and CE-CMRA were performed at 1.5 Tesla. Two radiologists evaluated the images regarding image quality (1 = poor, 4 = excellent), artifacts (1 = severe, 4 = none) and aortic pathologies. Readers measured the aortic diameters at defined levels in both techniques. Statistics included observer agreement for image scoring and diameter measurements and ROC analyses for comparison of the diagnostic performance of bSSFP and CE-CMRA. Results: Both readers observed no significant differences in image quality between bSSFP and CE-CMRA and found a median image quality score of 4 for both techniques (all p > .05). No significant differences were found regarding the frequency of image artifacts in both sequences (all p > .05). Sensitivity and specificity for detection of aortic dissections was 100% for both readers and techniques. Compared to bSSFP imaging, CE-CMRA resulted in higher diameters (mean bias, 0.9 mm; p .05), except for the distal graft anastomosis (p = .001). Using both techniques, the readers correctly identified a graft suture dehiscence with aneurysm formation requiring surgery. Conclusion: Unenhanced bSSFP CMR imaging allows for riskless aortic monitoring with high diagnostic accuracy in Marfan patients after aortic root surgery