Reverse shoulder arthroplasty with a cementless short metaphyseal humeral prosthesis without a stem: survivorship, early to mid-term clinical and radiological outcomes in a prospective study from an independent centre.

INTRODUCTION: The use of reverse total shoulder arthroplasty has increased for the management of cuff-deficient glenohumeral joint arthritis and fractures. With bone preservation being a major target in reverse shoulder arthroplasty, metaphyseal humeral components without a stem were developed. The aim of this study is to present the survivorship, functional and radiological outcomes of a novel short metaphyseal prosthesis without a diaphyseal stem from an independent centre. METHODS: Clinical function and radiological features of patients undergoing stemless reverse shoulder arthroplasty were prospectively recorded. Patients' demographics, indications for surgery, complications, functional and radiological assessment at the final follow-up as well as survivorship with the end point of revision for any reason were recorded. RESULTS: Between 2009 and 2016, 36 patients received 37 reverse shoulder arthroplasties with the stemless Verso prosthesis. Mean age of the patients was 76.9 years. The most common indication for surgery was cuff tear arthropathy. Mean follow-up was 3 years (range 1-7 years). Oxford shoulder score improved from an average of 11 pre-operatively (range 2-19) to 44 post-operatively (range 29-48) (p < 0.0001). There was one case of a deep post-operative infection that needed washout, liner exchange with retention of the prosthesis. Radiographic analysis showed no lucencies, or stress shielding around the humeral or glenoid components. Constant score at the final follow-up was on average 63 (range 35-86). Activities of daily living with requirement for internal and external rotation score (ADLEIR) was on average 12 pre-operatively (range 0-27) and 31 post-operatively (range 18-36) (p < 0.0001). There was 100% survivorship of the prosthesis in this early to mid-term study. CONCLUSION: This early to mid-term prospective study demonstrates excellent survivorship and radiological results of the Verso reverse shoulder replacement. It needs a simple reproducible technique, and the results have been replicated at an independent centre. This study underlines its survivorship in the early to mid-term and confirms lower incidence of complications such as instability, notching, loosening and the need for revision surgery. Most importantly, it conserves the humeral bone stock for revision arthroplasties in the future. Our results are similar to those of the currently published literature.

Simultaneous bilateral total hip arthroplasty dislocation with unilateral foot drop following closed reduction.

Dislocation following primary and revision arthroplasty is a well-recognised complication with an estimated incidence rate of 0.2-10%. We present a rare case of simultaneous bilateral total hip replacement dislocation, complicated by unilateral foot drop following closed reduction, with no improvement in neurological function at 6-month follow-up.

Measurements of Hepatic Metastasis on MR Imaging:: Assessment of Interobserver and Intersequence Variability.

RATIONALE AND OBJECTIVES: The purpose of the study was to investigate interobserver and intersequence variability in the measurement of hepatic metastasis on magnetic resonance imaging (MRI). MATERIALS AND METHODS: This retrospective study was conducted with an institutional review board-approved waiver of informed consent and was in compliance with the Health Insurance Portability and Accountability Act. We searched medical records at our institution for patients with histologically proven metastases to the liver who had undergone MRI from January 2008 to June 2010. We identified 20 patients with 30 measurable liver lesions. The liver lesions were measured on five different MRI sequences. A presenter radiologist selected and localized all metastatic lesions considered to be measurable according to the Response Evaluation Criteria in Solid Tumors, and these lesions were measured (Eisenhauer et al., 2009) by three radiologists independently. We calculated lesion-wise intraclass correlation coefficients (ICCs) to estimate interobserver and intersequence agreement in lesion diameter measurement. A Bland-Altman plot was used to estimate the limits of agreement between radiologists and MRI sequences. RESULTS: There were 30 metastases, and almost all of which had regular and well-defined margins. Interobserver ICCs were greater than 0.95 for different MRI sequences except for the measurements in apparent diffusion coefficient images. Intersequence ICCs were greater than 0.92. Bland-Altman plots between physicians confirmed that reader measurements were closely tied together, with small differences in means. CONCLUSIONS: MRI can reproducibly measure hepatic metastatic lesions without significant variability among interpreting radiologists or among MRI sequences, and is thus a reliable method for assessing the size of hepatic metastasis.

Now you see it, now you don't: visual illusions in radiology.

Visual illusions are distortions, alterations, or alternatives in the appearance of reality that result primarily from the sensory and perceptual processing mechanisms of the human visual system. These illusions are common phenomena in radiology, and it is important to understand them because they can create the illusion of disease, leading to incorrect image interpretation. Visual illusions in radiology can be organized according to the point in the visual system at which they emerge. Illusions of sensation, including Mach bands and background effect, are "lower-order" visual phenomena that occur as the eye and brain translate light into neural activity. Illusions of perception, such as ambiguous figures and distortion, occur in "higher-order" brain structures that are responsible for coalescing sensory input into a mental image interpreted by the mind. Illusions of image formation (eg, parallax), as the name implies, result from the way images are generated. Some visual illusions occur with all modalities, whereas others tend to be modality specific. The authors discuss a variety of visual illusions, describing their underlying psychologic and neuroscientific basis and demonstrating their relevance to radiology. A thorough understanding of visual illusions in radiology enhances diagnostic accuracy by minimizing the risk of mistaking illusions for disease.

Injuries associated with recreational horse riding and changes over the last 20 years: a review.

OBJECTIVE: To assess the incidence and distribution of recreational equestrian injuries seen in the Kent and Sussex region and review the available literature on this subject. DESIGN: This is a retrospective case series with historical controls. SETTING: Kent and Sussex region, England. MAIN OUTCOME MEASUREMENT: Injuries related to horses in the recreational setting. METHODS: Subjects were selected from our acute injury database. Notes of all patients presenting with horse riding-related injuries between January and December 2010 were reviewed. Skeletal injuries were confirmed using our Picture Archiving and Communications Systems (PACS) system. Data were tabulated and grouped using Microsoft Excel software. Statistics were calculated using Graph Pad software. RESULTS: During the study period, 155 patients presented with a total of 199 injuries related to horses, accounting for 0.3% of all presentations; 69% were soft tissue injuries. The most commonly affected areas were the extremities (77 patients, 49.7%) followed by injuries to the head (38 patients, 24.5%) and trunk (36 patients, 23.2%). Seventeen patients (11%) were admitted. Patients presenting with head injuries suffered significantly more injuries compared to other groups (1.65 compared to 1.4 injuries, p < 0.0002). CONCLUSION: A larger number of persons were riding for a longer period of the year compared to previous studies in the United Kingdom. There was also a shift in the patterns of injury seen in this population over the last two to three decades.

Acute abdominal pain and radiological pneumoperitoneum - always an indication for laparotomy?

Pneumoperitoneum in the presence of acute abdominal pain is well recognised as an indication for laparotomy. We present a case of acute abdominal pain in the presence of an incidental pneumoperitoneum secondary to the rupture of pneumatosis intestinalis. We will discuss the importance of clinical context in the diagnosis and management of pneumoperitoneum and pneumatosis intestinalis.

Utility of head CT in the evaluation of vertigo/dizziness in the emergency department.

Acute dizziness (including vertigo) is a common reason to visit the emergency room, and imaging with head CT is often performed initially to exclude a central cause. In this study, consecutive patients presenting with dizziness and undergoing head CT were retrospectively reviewed to determine diagnostic yield. Four hundred forty-eight consecutive head CTs in a representative sample of dizzy emergency room (ER) patients, including patients with other neurological symptoms, were reviewed to identify an acute or subacute cause for acute dizziness along with the frequency and modalities used in follow-up imaging. The diagnostic yield for head CT ordered in the ER for acute dizziness is low (2.2 %; 1.6 % for emergent findings), but MRI changes the diagnosis up to 16 % of the time, acutely in 8 % of cases. Consistent with the American College of Radiology appropriateness criteria and the literature, this study suggests a low diagnostic yield for CT in the evaluation of acute dizziness but an important role for MRI in appropriately selected cases.

Inflow effects on hemodynamic responses characterized by event-related fMRI using gradient-echo EPI sequences.

The purpose of this study is to determine whether blood inflow impacts the temporal behavior of BOLD-contrast fMRI signal changes in a typical event-related paradigm. The inflow contributions in the hemodynamic response to repeated single trials of short visual stimulation were assessed with a gradient-echo EPI sequence by altering the flip angle (FA) from 30 degrees to 90 degrees at a repetition time of 1 s. For each FA condition (30 degrees, 60 degrees, and 90 degrees), 30 trials were performed on 15 healthy volunteers on a 3T MRI scanner. Comparing the percent BOLD contrast, prominent inflow effects were found with statistical significance between the 90 degrees- and 30 degrees-FA conditions (0.73 +/- 0.15 versus 0.67 +/- 0.12%, p=0.028). BOLD responses with FA=30 degrees exhibited latencies significantly slower than those with FA=90 degrees (3.69 +/- 0.39 s versus 3.37 +/- 0.28 s, p=0.001). The falling time of the 30 degrees-FA responses was earlier but not statistically different from that of the 90 degrees-FA (8.17 +/- 1.04 s versus 8.03 +/- 1.15 s, p=0.3). Using a voxelwise analysis, the latency variations of the activated visual areas were determined at several contrast-to-noise ratio (CNR) levels (controlled by averaging different numbers of randomly selected trials). The latency variations from the 90 degrees-FA responses were greater at lower CNR but similar at higher CNR levels when comparing to the 30 degrees-FA ones. This study suggests that inflow effects contribute to the BOLD signal, resulting in hemodynamic response with shorter latency.