Glenoid bone strain after anatomical total shoulder arthroplasty: In vitro measurements with micro-CT and digital volume correlation.

Glenoid implant loosening remains a major source of failure and concern after anatomical total shoulder arthroplasty (aTSA). It is assumed to be associated with eccentric loading and excessive bone strain, but direct measurement of bone strain after aTSA is not available yet. Therefore, our objective was to develop an in vitro technique for measuring bone strain around a loaded glenoid implant. A custom loading device (1500 N) was designed to fit within a micro-CT scanner, to use digital volume correlation for measuring displacement and calculating strain. Errors were evaluated with three pairs of unloaded scans. The average displacement random error of three pairs of unloaded scans was 6.1 µm. Corresponding systematic and random errors of strain components were less than 806.0 µÎµ and 2039.9 µÎµ, respectively. The average strain accuracy (MAER) and precision (SDER) were 694.3 µÎµ and 440.3 µÎµ, respectively. The loaded minimum principal strain (8738.9 µÎµ) was 12.6 times higher than the MAER (694.3 µÎµ) on average, and was above the MAER for most of the glenoid bone volume (98.1%). Therefore, this technique proves to be accurate and precise enough to eventually compare glenoid implant designs, fixation techniques, or to validate numerical models of specimens under similar loading.

Dual-energy computed tomography in calcium pyrophosphate deposition: initial clinical experience.

OBJECTIVE: To determine the dual-energy computed tomography (DECT) attenuation properties of meniscal calcifications in calcium pyrophosphate deposition (CPPD) in vivo, and assess whether DECT was able to discriminate meniscal CPP deposits from calcium hydroxyapatite (HA) in subchondral and trabecular bone. METHOD: Patients with clinical suspicion of crystal-related arthropathy (gout and/or CPPD) and knee DECT scans were retrospectively assigned to CPPD (n = 19) or control (n = 21) groups depending on the presence/absence of chondrocalcinosis on DECT. Two observers drew standardized regions of interest (ROI) in meniscal calcifications, non-calcified menisci, as well as subchondral and trabecular bone. Five DECT parameters were obtained: CT numbers (HU) at 80 and 140 kV, dual-energy index (DEI), electron density (ρe), and effective atomic number (Zeff). The four different knee structures were compared within/between patients and controls using linear mixed models, adjusting for confounders. RESULTS: Meniscal calcifications (n = 89) in CPPD patients had mean ± SD CT numbers at 80 and 140 kV of 257 ± 64 and 201 ± 48 HU, respectively; with a DEI of 0.023 ± 0.007, and ρe and Zeff of 140 ± 35 and 8.8 ± 0.3, respectively. Meniscal CPP deposits were readily distinguished from calcium HA in subchondral and trabecular bone (p ≤ 0.001), except at 80 kV separately (p = 0.74). Zeff and ρe both significantly differed between CPP deposits and calcium HA in subchondral and trabecular bone (p < 0.0001). CONCLUSION: This proof-of-concept study shows that DECT has the potential to discriminate meniscal CPP deposits from calcium HA in subchondral and trabecular bone in vivo, paving the way for the non-invasive biochemical signature assessment of intra- and juxta-articular calcium crystal deposits.

A semi-automated quantitative CT method for measuring rotator cuff muscle degeneration in shoulders with primary osteoarthritis.

BACKGROUND: Rotator cuff muscle degeneration is an important parameter to consider when planning shoulder arthroplasty. HYPOTHESIS: We hypothesized that rotator cuff muscle degeneration is correlated with scapulohumeral subluxation in patients planned for anatomical total shoulder arthroplasty (TSA). MATERIALS AND METHODS: We developed a semi-automated quantitative CT method to measure rotator cuff muscle degeneration, and retrospectively analyzed 107 preoperative shoulder CT scans of patients with primary osteoarthritis. On a standardized sagittal-oblique CT slice perpendicular to the scapular axis, two observers measured the cross-sectional areas of residual rotator cuff muscle tissues, normalized by the estimated area of healthy muscles. Muscle degeneration was quantified in a semi-automated manner, and divided into atrophy and fatty infiltration. Scapulohumeral subluxation was determined in 3D as the distance between the humeral head center and the glenoid surface center, projected on the same CT slice, and normalized by the humeral head radius. We tested all potential correlations between muscle degeneration and scapulohumeral subluxation. RESULTS: Muscle degeneration, primarily due to atrophy, predominated in the supraspinatus; it varied from 0.8% to 88.8%. Scapulohumeral subluxation varied from 2.5% to 72.9%, and was mainly in a posterior and postero-superior orientation. There was a significant but weak correlation between the amount of subluxation and both supraspinatus (R=0.207, P=0.032) and infraspinatus (R=0.225, P=0.020) degeneration. Inter- and intra-observer reproducibility of muscle degeneration measurements were both excellent (ICCs range=0.955-0.987 and 0.971-0.988, respectively). CONCLUSION: This new semi-automated CT method allows to quantitatively and reproducibly measure rotator cuff muscle degeneration in shoulders with primary osteoarthritis. Muscle degeneration is weakly correlated with scapulohumeral subluxation in patients planned for anatomical TSA. LEVEL OF EVIDENCE: Level IV. TYPE OF STUDY: Diagnostic retrospective study.

2016 updated EULAR evidence-based recommendations for the management of gout.

BACKGROUND: New drugs and new evidence concerning the use of established treatments have become available since the publication of the first European League Against Rheumatism (EULAR) recommendations for the management of gout, in 2006. This situation has prompted a systematic review and update of the 2006 recommendations. METHODS: The EULAR task force consisted of 15 rheumatologists, 1 radiologist, 2 general practitioners, 1 research fellow, 2 patients and 3 experts in epidemiology/methodology from 12 European countries. A systematic review of the literature concerning all aspects of gout treatments was performed. Subsequently, recommendations were formulated by use of a Delphi consensus approach. RESULTS: Three overarching principles and 11 key recommendations were generated. For the treatment of flare, colchicine, non-steroidal anti-inflammatory drugs (NSAIDs), oral or intra-articular steroids or a combination are recommended. In patients with frequent flare and contraindications to colchicine, NSAIDs and corticosteroids, an interleukin-1 blocker should be considered. In addition to education and a non-pharmacological management approach, urate-lowering therapy (ULT) should be considered from the first presentation of the disease, and serum uric acid (SUA) levels should be maintained at<6 mg/dL (360 µmol/L) and <5 mg/dL (300 µmol/L) in those with severe gout. Allopurinol is recommended as first-line ULT and its dosage should be adjusted according to renal function. If the SUA target cannot be achieved with allopurinol, then febuxostat, a uricosuric or combining a xanthine oxidase inhibitor with a uricosuric should be considered. For patients with refractory gout, pegloticase is recommended. CONCLUSIONS: These recommendations aim to inform physicians and patients about the non-pharmacological and pharmacological treatments for gout and to provide the best strategies to achieve the predefined urate target to cure the disease.

Intravoxel incoherent motion perfusion imaging in acute stroke: initial clinical experience.

INTRODUCTION: Intravoxel incoherent motion (IVIM) imaging is an MRI perfusion technique that uses a diffusion-weighted sequence with multiple b values and a bi-compartmental signal model to measure the so-called pseudo-diffusion of blood caused by its passage through the microvascular network. The goal of the current study was to assess the feasibility of IVIM perfusion fraction imaging in patients with acute stroke. METHODS: Images were collected in 17 patients with acute stroke. Exclusion criteria were onset of symptoms to imaging >5 days, hemorrhagic transformation, infratentorial lesions, small lesions <0.5 cm in minimal diameter and hemodynamic instability. IVIM imaging was performed at 3 T, using a standard spin-echo Stejskal-Tanner pulsed gradients diffusion-weighted sequence, using 16 b values from 0 to 900 s/mm(2). Image quality was assessed by two radiologists, and quantitative analysis was performed in regions of interest placed in the stroke area, defined by thresholding the apparent diffusion coefficient maps, as well as in the contralateral region. RESULTS: IVIM perfusion fraction maps showed an area of decreased perfusion fraction f in the region of decreased apparent diffusion coefficient. Quantitative analysis showed a statistically significant decrease in both IVIM perfusion fraction f (0.026 ± 0.019 vs. 0.056 ± 0.025, p=2.2 · 10(-6)) and diffusion coefficient D compared with the contralateral side (3.9 ± 0.79 · 10(-4) vs. 7.5 ± 0.86 · 10(-4) mm(2)/s, p=1.3 · 10(-20)). CONCLUSION: IVIM perfusion fraction imaging is feasible in acute stroke. IVIM perfusion fraction is significantly reduced in the visible infarct. Further studies should evaluate the potential for IVIM to predict clinical outcome and treatment response.

[Role of imaging in the diagnosis and follow-up of rheumatoid arthritis]. / Rôle de l'imagerie dans le diagnostic et le suivi de la polyarthrite rhumatoïde.

Cross-sectional imaging techniques such as magnetic resonance imaging and ultrasound are becoming essential tools not only for making an early diagnosis of rheumatoid arthritis, but also to help clarify the prognosis of the disease and better assess the response to various therapies. This article summarises the recommendations established in 2013 by the European League Against Rheumatism on the role of imaging in the diagnosis and follow-up of rheumatoid arthritis, while adding comments and emphasising on our Swiss experience with the use of ultrasound.

MDCT imaging of calcinosis in systemic sclerosis.

Calcinosis is a typical feature of systemic sclerosis (SSc) and can be found in many different tissues including the superficial soft tissues, periarticular structures, muscles, and tendons. It can also provoke erosive changes on bones. Investigation is conducted most often with plain radiographs. However, when a more detailed assessment is necessary, multidetector computed tomography (MDCT) is helpful owing to its multiplanar reformat (MPR) ability. The purpose of this review is to provide an overview of the various appearances of calcinosis in SSc patients as visualized at MDCT.