Computed tomography of subchondral bone and osteophytes in hip osteoarthritis: the shape of things to come?

Bone is a fundamental component of the disordered joint homeostasis seen in osteoarthritis, a disease that has been primarily characterized by the breakdown of articular cartilage accompanied by local bone changes and a limited degree of joint inflammation. In this review we consider the role of computed tomography imaging and computational analysis in osteoarthritis research, focusing on subchondral bone and osteophytes in the hip. We relate what is already known in this area to what could be explored through this approach in the future in relation to both clinical research trials and the underlying cellular and molecular science of osteoarthritis. We also consider how this area of research could impact on our understanding of the genetics of osteoarthritis

Infective endocarditis caused by Arcanobacterium haemolyticum: a case report

Arcanobacterium haemolyticum is an organism that commonly causes pharyngitis and wound infections. It does not usually cause systemic invasive disease. The organism presents a difficult diagnostic problem because the Clinical Microbiology laboratory has a propensity to view them as diphtheroid organisms of the Corynebacterium species, thus contaminants or normal flora. We describe a case of a 21-year-old female who had endocarditis with cerebral emboli due to Arcanobacterium haemolyticum. This rare condition is associated with significant mortality and to the best of our knowledge; this is the first successfully treated case of A. haemolyticum endocarditis complicated by embolic phenomenon

Advances in osteoarthritis imaging: What will make it into clinical practice?

This is the final version of the article. It first appeared from the British Orthopaedic Association via http://www.boa.ac.uk/publications/jto-vol-4-issue-3/© British Orthopaedic Association 2016 Osteoarthritis is one of the fastest increasing global health problems, causing pain and disability. End stage disease is treated effectively with joint replacement, but the number of replacements is increasing year-on-year, with increased costs for already stretched healthcare systems

Quantitative 3D analysis of bone in hip osteoarthritis using clinical computed tomography.

OBJECTIVE: To assess the relationship between proximal femoral cortical bone thickness and radiological hip osteoarthritis using quantitative 3D analysis of clinical computed tomography (CT) data. METHODS: Image analysis was performed on clinical CT imaging data from 203 female volunteers with a technique called cortical bone mapping (CBM). Colour thickness maps were created for each proximal femur. Statistical parametric mapping was performed to identify statistically significant differences in cortical bone thickness that corresponded with the severity of radiological hip osteoarthritis. Kellgren and Lawrence (K&L) grade, minimum joint space width (JSW) and a novel CT-based osteophyte score were also blindly assessed from the CT data. RESULTS: For each increase in K&L grade, cortical thickness increased by up to 25 % in distinct areas of the superolateral femoral head-neck junction and superior subchondral bone plate. For increasing severity of CT osteophytes, the increase in cortical thickness was more circumferential, involving a wider portion of the head-neck junction, with up to a 7 % increase in cortical thickness per increment in score. Results were not significant for minimum JSW. CONCLUSIONS: These findings indicate that quantitative 3D analysis of the proximal femur can identify changes in cortical bone thickness relevant to structural hip osteoarthritis. KEY POINTS: • CT is being increasingly used to assess bony involvement in osteoarthritis • CBM provides accurate and reliable quantitative analysis of cortical bone thickness • Cortical bone is thicker at the superior femoral head-neck with worse osteoarthritis • Regions of increased thickness co-locate with impingement and osteophyte formation • Quantitative 3D bone analysis could enable clinical disease prediction and therapy development.TT acknowledges the support of an Evelyn Trust Clinical Training Fellowship award (RG65411). KP acknowledges support of an Arthritis Research UK Research Progression award (RG66087), and the Cambridge NIHR Biomedical Research Centre (RG64245). None of the funding sources had a role in study design, data handling, writing of the report, or decision to submit the paper for publication.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00330-015-4048-

The Segond fracture occurs at the site of lowest sub-entheseal trabecular bone volume fraction on the tibial plateau.

In a series of human cadaveric experiments, Dr. Paul Segond first described the avulsion injury occurring at the anterolateral tibial plateau that later took his name. The fracture is thought to arise as a consequence of excessive tibia internal rotation which often also elicits damage to other connective tissue of the knee. The exact mechanism behind the avulsion is, however, unclear. A number of ligamentous structures have been proposed in separate studies to insert into the Segond fragment. Suggestions include the iliotibial band (ITB), biceps femoris and the controversial 'anterolateral ligament' (ALL). Despite increasing knowledge of tibial plateau bony microarchitecture in both healthy and disease states, no studies have yet, to our knowledge, considered the role of tibial sub-entheseal bone structure in pathogenesis of the Segond fracture. The goal of this study was thus to elucidate the differences in trabecular properties at regions across the tibial plateau in order to provide an explanation for the susceptibility of the anterolateral region to avulsion injury. Twenty human tibial plateaus from cadaveric donors were dissected and imaged using a Nikon-XTH225-μCT scanner with <80 μm isotropic voxel size. Scans were reconstructed using MicroView 3D Image Viewer and Analysis Tool. Subsequent virtual biopsy at ten anatomically defined regions of interest (ROI) generated estimates of bone volume fraction ('bone volume divided by total volume' (BV/TV)). The overall mean BV/TV value across all 20 tibiae and all 10 ROIs was 0.271. Univariate repeated-measurements ANOVA demonstrated that BV/TV values differed between ROIs. BV/TV values at the Segond site (Sα, Sβ or Sγ) were lower than all other ROIs at 0.195, 0.192 and 0.193, respectively. This suggests that, notwithstanding inter- and intra-specimen variation, the Segond site tends to have a lower trabecular bone volume fraction than entheseal sites elsewhere on the tibia. Since BV/TV correlates with tensile and torsional strength, the lower BV/TV at the Segond site could equate to a region of local weakness in certain individuals which predisposes them to an avulsion injury following the application of force from excessive internal rotation. The low BV/TV recorded at the Segond site also challenges the idea that the fracture occurs due to pull from a discrete 'anterolateral ligament', as the tension exerted focally would be expected to elicit a hypertrophic response in line with Frost's Mechanostat hypothesis. Our data would instead agree with the aforementioned reports of the fibrous band at the Segond site being part of a broader insertion of an 'anterolateral complex'

Knee joint distraction results in MRI cartilage thickness increase up to 10 years after treatment

OBJECTIVES: Knee joint distraction (KJD) has been shown to result in long-term clinical improvement and short-term cartilage restoration in young OA patients. The objective of the current study was to evaluate MRI cartilage thickness up to 10 years after KJD treatment, using a 3D surface-based approach. METHODS: Twenty end-stage knee OA patients were treated with KJD. MRI scans (1.5 T) were performed before and at 1, 2, 5, 7, and 10 years after treatment. Tibia and femur cartilage segmentation and registration to a canonical surface were performed semi-automatically. Statistical parametric mapping with linear mixed models was used to analyse whole-joint changes. The influence of baseline patient characteristics was analysed with statistical parametric mapping using linear regression. Relevant weight-bearing parts of the femur were selected to obtain the average cartilage thickness in the femur and tibia of the most- (MAC) and least-affected compartment. These compartmental changes over time were analysed using repeated measures ANOVA; missing data was imputed. In all cases, P 0.05). Compartmental analyses showed significant short- and long-term thickness increase in the tibia and femur MAC (all P <0.05). CONCLUSION: KJD results in significant short- and long-term cartilage regeneration, up to 10 years post-treatment. TRIAL REGISTRATION: Netherlands Trial Register, https://www.trialregister.nl, NL419

Salmonella pyomyositis complicating sickle cell anemia: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pyomyositis is a bacterial infection of skeletal muscle and a rare complication of sickle cell anemia. It may present a difficult problem in diagnosis, leading to delay in appropriate treatment and development of complications including abscess formation and osteomyelitis.</p> <p>Case presentation</p> <p>We report the case of a 44-year-old Afro-Caribbean woman with homozygous sickle cell disease who presented with chest crisis and later developed pyomyositis of her hip and pelvic muscles. <it>Salmonella agbeni </it>was isolated from blood cultures and magnetic resonance imaging confirmed the diagnosis in this case. It is noteworthy of this case that there were no antecedent signs of gastroenteritis. Drainage was not appropriate and she was treated with intravenous antibiotics for six weeks.</p> <p>Conclusions</p> <p>Focal Salmonella infections are uncommon in soft tissue. Pyomyositis should be considered in patients with sickle cell anemia that continue to have muscle pain and high fevers, despite initial management of their sickle cell crisis. Radiological imaging, particularly magnetic resonance imaging, is a crucial tool in establishing the diagnosis.</p

Quantitative Three-dimensional Assessment of Knee Joint Space Width from Weight-bearing CT.

Background Imaging of structural disease in osteoarthritis has traditionally relied on MRI and radiography. Joint space mapping (JSM) can be used to quantitatively map joint space width (JSW) in three dimensions from CT images. Purpose To demonstrate the reproducibility, repeatability, and feasibility of JSM of the knee using weight-bearing CT images. Materials and Methods Two convenience samples of weight-bearing CT images of left and right knees with radiographic Kellgren-Lawrence grades (KLGs) less than or equal to 2 were acquired from 2014 to 2018 and were analyzed retrospectively with JSM to deliver three-dimensional JSW maps. For reproducibility, images of three sets of knees were used for novice training, and then the JSM output was compared against an expert's assessment. JSM was also performed on 2-week follow-up images in the second cohort, yielding three-dimensional JSW difference maps for repeatability. Statistical parametric mapping was performed on all knee imaging data (KLG, 0-4) to show the feasibility of a surface-based analysis in three dimensions. Results Reproducibility (in 20 individuals; mean age, 58 years ± 7 [standard deviation]; mean body mass index, 28 kg/m2 ± 6; 14 women) and repeatability (in nine individuals; mean age, 53 years ± 6; mean body mass index, 26 kg/m2 ± 4; seven women) reached their lowest performance at a smallest detectable difference less than ±0.1 mm in the central medial tibiofemoral joint space for individuals without radiographically demonstrated disease. The average root mean square coefficient of variation was less than 5% across all groups. Statistical parametric mapping (33 individuals; mean age, 57 years ± 7; mean body mass index, 27 kg/m2 ± 6; 23 women) showed that the central-to-posterior medial joint space was significantly narrower by 0.5 mm for each incremental increase in the KLG (threshold P < .05). One knee (KLG, 2) demonstrated a baseline versus 24-month change in its three-dimensional JSW distribution that was beyond the smallest detectable difference across the lateral joint space. Conclusion Joint space mapping of the knee using weight-bearing CT images is feasible, demonstrating a relationship between the three-dimensional joint space width distribution and structural joint disease. It is reliably learned by novice users, can be personalized for disease phenotypes, and can be used to achieve a smallest detectable difference that is at least 50% smaller than that reported to be achieved at the highest performance level in radiography. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Roemer in this issue

Professional development and research are being neglected: a commentary on the 2019 RCR radiologists’ supporting professional activities (SPA) survey

When the National Health Service (NHS) acquired a statutory duty of care for quality in 1998, clinical governance became a mandatory and intrinsic part of modern medicine. Defined as “a framework through which NHS organisations are accountable for continuously improving the quality of their services and safe-guarding high standards of care by creating an environment in which excellence in clinical care will flourish”,1 the vehicle for NHS consultants to enact clinical governance was supporting professional activity (SPA). All activities that underpin direct clinical care (DCC) are encouraged during SPA time, including professional development, research, audit, teaching, clinical management, appraisal, and job planning.2,3 Adequate time for SPAs alongside DCC is therefore crucial for NHS consultants to\ud maintain excellence in clinical care.3 The recently published Royal College of Radiologists (RCR) Survey on Radiologists’ SPA4 has demonstrated three recurring themes, which are widely recognised to be growing concerns for our specialty

Multiparametric 3-D analysis of bone and joint space width at the knee from weight bearing computed tomography

Objective: Computed tomography (CT) can deliver multiple parameters relevant to osteoarthritis. In this study we demonstrate that a 3-D multiparametric approach at the weight-bearing knee with cone beam CT is feasible, can include multiple parameters from across the joint space, and can reveal stronger relationships with disease status when parameters are combined. Design: Weight-bearing (WBCT) images of the knees of 33 participants were analyzed with joint space mapping and cortical bone mapping to deliver joint space width (JSW), subchondral bone plate thickness, endocortical thickness, and trabecular attenuation on both sides of the joint. All data were co-localized to the same canonical surface. Statistical parametric mapping (SPM) was applied in uni- and multivariate models to demonstrate significant dependence of parameters on Kellgren & Lawrence grade (KLG). Correlations between JSW and bony parameters and 2-week test-retest repeatability were also calculated. Results: SPM revealed that the central-to-posterior medial tibiofemoral joint space was significantly narrowed by up to 0.5 mm with significantly higher tibial trabecular attenuation — up to 50 attenuation units for each increment in KLG as a single parameter — and in a wider distribution when combined with others (p<0.05). They were also more strongly correlated with worsening KLG grade category. Test-retest repeatability was subvoxel (0.37 mm) for nearly all thickness parameters. Conclusions: 3-D JSW and tibial trabecular attenuation are repeatable and significantly dependent on radiographic disease severity at the weight-bearing knee joint and even more so in combination. A quantitative multiparametric approach with WBCT may have potential for more sensitive investigation of disease progression in osteoarthritis