Local and Systemic Side Effects of Corticosteroid Injections for Musculoskeletal Indications.

Corticosteroid injections can be associated with a range of potential side effects, which may be classified as local or systemic and further stratified as immediate or delayed in onset. Radiologists performing image-guided musculoskeletal injections should recognize the potential side effects of corticosteroid medication when counseling patients before injection and consider such side effects in planning individual injections. This Review summarizes the available evidence regarding the local and systemic side effects of corticosteroid injections performed for musculoskeletal indications. Local side effects include postinjection flare, skin hypopigmentation and atrophy, infection, tendon rupture, accelerated progression of osteoarthritis, and osseous injury. Systemic side effects include adrenal suppression or insufficiency, facial flushing, hypertension, hyperglycemia, and osteoporosis. Additional targeted counseling is warranted regarding side effects that are specific to certain patient populations (i.e., premenopausal women, patients with diabetes, athletes, and pediatric patients). Corticosteroid injections are contraindicated in the presence of superficial or deep infection, fracture, or a prosthetic joint. Guidelines on the frequency, duration, and maximal lifetime use of corticosteroid injections are currently lacking. Further research is needed regarding the long-term complications of continuous corticosteroid use, particularly with regard to osseous effects.

Percutaneous Interventions for Injuries in Athletes: Implications on Return to Play.

For nonsurgical musculoskeletal (MSK) injuries in athletes, image-guided percutaneous intervention may aid in recovery and decrease return to play (RTP) time. These interventions fall into two major categories: to reduce inflammation (and therefore alleviate pain) or to promote healing. This review describes the risks and benefits of the various percutaneous interventions in MSK athletic injury and surveys the literature regarding the implication of these interventions on RTP.

Presence of subchondral fracture in cases diagnosed as transient osteoporosis of the hip: a retrospective independent reader-based study.

OBJECTIVE: Transient osteoporosis of the hip (TOH) is an uncommon, typically self-limited diagnosis of uncertain etiology. We hypothesize that TOH represents an underlying subchondral fracture, and a discrete fracture line can often be detected on high-resolution MRI. MATERIALS AND METHODS: A retrospective PACS query identified patients meeting imaging criteria for TOH with intense bone marrow edema (BME) in the femoral head on MRI. Those with poor quality studies, other underlying pathologies, or antecedent trauma were excluded. Three musculoskeletal radiologists independently reviewed each case for presence of a definite subchondral fracture line on small field of view (FOV) MR images of the affected hip. Extent of BME, reciprocal acetabular BME, and joint effusion size were also recorded. Binomial logistic regression was performed to determine statistically significant predictors of subchondral fracture. RESULTS: Fifty patients met inclusion criteria (29 females, 0 pregnant). Mean age was 62±12 years (range 35-84). Average duration of symptoms before MRI was 102±135 days. Ten patients had bone densitometry within 2 years of MRI, six demonstrating osteopenia or osteoporosis. Subchondral fractures were unanimously identified in 44/50 (88%). Interclass correlation coefficient with absolute agreement was 0.73, 95% CI (0.57-0.84), indicating near-excellent agreement. Most cases demonstrated a large joint effusion (23/50, 46%) and acetabular BME (31/50, 62%). Increasing size of joint effusion was a statistically significant predictor of subchondral fracture (p=0.05), with 6.9 higher odds. There was a strong correlation with osteopenia/osteoporosis and fracture (p<0.001). CONCLUSION: Discrete subchondral fractures were identified unanimously on small FOV imaging in the majority of TOH cases.

The zebrafish cohesin protein Sgo1 is required for cardiac function and eye development.

BACKGROUND: Cohesinopathies is a term that refers to/covers rare genetic diseases caused by mutations in the cohesin complex proteins. The cohesin complex is a multiprotein complex that facilitates different aspects of cell division, gene transcription, DNA damage repair, and chromosome architecture. Shugoshin proteins prevent the cohesin complex from premature dissociation from chromatids during cell division. Patients with a homozygous missense mutation in SGO1, which encodes for Shugoshin1, have problems with normal pacing of the heart and gut. RESULTS: To study the role of shugoshin during embryo development, we mutated the zebrafish sgo1 gene. Homozygous sgo1 mutant embryos display various phenotypes related to different organs, including a reduced heart rate accompanied by reduced cardiac function. In addition, sgo1 mutants are vision-impaired as a consequence of structurally defective and partially non-functional photoreceptor cells. Furthermore, the sgo1 mutants display reduced food intake and early lethality. CONCLUSION: We have generated a zebrafish model of Sgo1 that showed its importance during organ development and function.

Establishing a Women-in-Radiology Group: A Toolkit From the American Association for Women in Radiology.

Despite increasing representation in medical schools and surgical specialties, recruitment of women into radiology has failed to exhibit commensurate growth. Furthermore, women are less likely than men to advance to leadership roles in radiology. A women-in-radiology (WIR) group provides a robust support system that has been shown to produce numerous benefits to the group's individual participants as well as the group's institution or practice. These benefits include development of mentor-ship relationships, guidance of career trajectories, improved camaraderie, increased participation in scholarly projects, and increased awareness of gender-specific issues. This article describes a recommended pathway to establishing a WIR group, with the goal of fostering sponsorship and promoting leadership, recruitment, and advancement of women in radiology. We consider barriers to implementation and review resources to facilitate success, including a range of resources provided by the American Association for Women in Radiology. By implementing the provided framework, radiologists at any career stage can start a WIR group, to promote the advancement of their female colleagues.

Minimally Invasive Ultrasound-Guided Carpal Tunnel Release Improves Long-Term Clinical Outcomes in Carpal Tunnel Syndrome.

BACKGROUND. Ultrasound guidance allows performance of carpal tunnel release with smaller incisions and quicker recovery than traditional open or endoscopic surgery. OBJECTIVE. The purpose of this study was to evaluate the long-term effectiveness of ultrasound-guided carpal tunnel release in improving function and discomfort in patients with carpal tunnel syndrome. METHODS. Retrospective review was conducted of 61 ultrasound-guided carpal tunnel release procedures performed on 46 patients (15 bilateral procedures) with clinically diagnosed carpal tunnel syndrome. The procedures were performed with a single-use transection device and local anesthesia at an outpatient radiology office. Patients answered three questionnaires (Quick Disabilities of the Arm, Shoulder, and Hand [QDASH] and two parts of the Boston Carpal Tunnel Syndrome Questionnaire-the symptom severity [BCTSQ-SS] and functional status [BCTSQ-FS] scales) to assess the function of and discomfort in the affected wrist immediately before and 2 weeks and at least 1 year after the procedure. Higher scores indicated increasing disability. Patients also answered a global satisfaction question at follow-up. Preprocedure and postprocedure scores were compared by paired Wilcoxon signed rank tests. RESULTS. The 46 patients (25 women, 21 men; mean age, 60.6 years; range, 21-80 years) had median preprocedure scores of 45.4 for QDASH, 3.2 for BCTSQ-SS, and 2.5 for BCTSQ-FS. The median scores 2 weeks after the procedure were 22.5 for QDASH, 1.7 for BCTSQ-SS, and 1.9 for BCTSQ-FS. All scores decreased (p < .001) from preprocedure scores and surpassed reference standards for clinically important difference in scores. Follow-up questionnaires obtained for 90% (55/61) of wrists a median of 1.7 years (range, 1.0-2.8 years) after the procedure showed further declines (p < .001) in median scores: 2.3 for QDASH, 1.2 for BCTSQ-SS, and 1.1 for BCTSQ-FS. At long-term follow-up evaluation, 96% (52/54) of wrists had lower QDASH and 98% (53/54) had lower BCTSQ (average of BCTSQ-SS and BCTSQ-FS) scores compared with the preprocedure scores. Among the patients who participated in the survey, 93% (37/40) were satisfied or very satisfied with the long-term outcomes. No immediately postoperative complications occurred. Two patients needed surgical intervention 8 and 10 days after surgery, one for infection after injury and one for posttraumatic compartment syndrome. CONCLUSION. Ultrasound-guided carpal tunnel release quickly improves hand function and reduces hand discomfort; improvement persists beyond 1 year. CLINICAL IMPACT. Ultrasound-guided carpal tunnel release may be a safe, effective, and less invasive alternative to traditional surgery.

The Evolving Roles of MRI and Ultrasound in First-Line Imaging of Rotator Cuff Injuries.

Rotator cuff tears are the most likely source of shoulder pain in adults and may cause protracted disability. Management of rotator cuff tears is associated with considerable costs. Accurate diagnosis can guide surgical planning and help achieve a favorable clinical outcome. Although radiography remains the initial imaging test for shoulder injury, the roles of MRI and ultrasound (US) as first-line imaging after radiography are evolving. This article leverages current literature and the practical experience of subspecialty musculoskeletal radiologists from different institutions in describing a practical approach to imaging rotator cuff pathology. Both MRI and US are accurate for identifying rotator cuff tears, but each has advantages and shortcomings. As both modalities currently represent reasonable first-line approaches, considerable practice variation has evolved. Given the low cost of US, imagers should strive to optimize the quality of shoulder US examinations and to build referrer confidence in this modality. The roles of direct CT and MR arthrography as well as imaging evaluation of the postoperative rotator cuff are also considered. Through careful selection among the available imaging modalities and optimal performance and interpretation of such examinations, radiologists can positively contribute to the diagnosis and treatment of patients with rotator cuff injuries.

Potential clinical impact of reporting breast arterial calcifications on screening mammograms in women without known coronary artery disease.

Cardiovascular disease remains a leading cause of death in women. 10-year likelihood for a cardiovascular event is determined by the American College of Cardiology Atherosclerotic Cardiovascular disease risk score calculator (ASVCD); however, this does not encompass risk factors unique to women. Breast arterial calcifications (BAC) detected on screening mammography may serve as a proxy for coronary atherosclerosis (CAC) in women. Our purpose was to investigate the correlation between BAC and CAC on imaging in women without a diagnosis of atherosclerosis to determine the potential clinical impact. Retrospective review was performed on a cohort of females evaluated by internists at our institution in 2019. Study patients had a screening mammogram within 1 year of a noncardiac chest CT. Clinical data were collected to determine ASCVD risk score. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of BAC in detecting CAC were determined. 222 women met inclusion criteria, ranging from 41 to 77 years of age, among which 25% (56/222) had BAC. 84% (47/56) of women with BAC had CAC on CT, yielding a sensitivity, specificity, PPV, and NPV of 51%, 93%, 84%, and 72%, respectively. Of the 47 patients who had both BAC and CAC, 66% had an unknown or low-to-borderline ASCVD score. Women with BACs have a high specificity for CAC. The reporting of BACs should prompt clinicians to risk stratify women for atherosclerotic disease. These women may otherwise be undetected by conventional risk calculators.

Extensor mechanism tendinopathy in patients with lateral patellar maltracking.

OBJECTIVE: Patellar maltracking is an important subset of patellofemoral pain syndrome. We hypothesize that maltracking patients have an increased incidence of extensor mechanism dysfunction due to repetitive attempts at stabilization of the patella. Our purpose is to delineate imaging features to identify maltracking patients at risk for extensor mechanism tendinopathy. MATERIALS AND METHODS: Retrospective review of knee MRIs performed for anterior knee pain over a year was conducted to identify 218 studies with imaging findings of maltracking. The cases were evaluated for the presence and degree of patellar and quadriceps tendinopathy, tibial tuberosity-trochlear groove distance (TT-TG) and the distribution and grade of patellofemoral chondrosis. Cases were compared to 100 healthy, age-matched control knee MRIs. RESULTS: The mean age of maltracking patients with either patellar or quadriceps tendinosis was 41.2 years versus 48.2 years in the control population (p = 0.037). The TT-TG was significantly higher in maltracking patients with either patellar or quadriceps tendinosis at 16.49 mm versus 14.99 mm (p = 0.006). Maltrackers with isolated lateral patellofemoral chondrosis had a higher mean TT-TG at 17.4 mm versus 15.4 mm (p = 0.007). Extensor mechanism tendinosis was increased in the maltracking population compared to the controls at 57.8% versus 27.3% (p = 0.004). CONCLUSION: Extensor mechanism tendinosis is more common in the maltracking population and occurs at a younger age. TT-TG distance is significantly increased in patients with extensor mechanism dysfunction and in patients with isolated lateral patellofemoral chondrosis. TT-TG measurement can be used independently to identifying maltrackers who may be at risk for future complications.

Prevalence of lateral patellofemoral maltracking and associated complications in patients with Osgood Schlatter disease.

OBJECTIVE: To evaluate adults with history of Osgood Schlatter disease (OSD) for imaging features of lateral patellofemoral maltracking. METHODS: In a span of four years, 10,181 unique non-contrast knee MRIs were performed on patients aged 20-50. Patients with acute trauma, prior surgery, and synovial pathologies were excluded. 171 exams had imaging findings of OSD, and an age-matched control group of 342 patients without OSD was randomly selected. Two radiologists retrospectively reviewed MRIs for features of lateral patellofemoral maltracking. Maltracking was defined as edema in superolateral Hoffa's fat or a tibial tuberosity-trochlear groove (TT-TG) distance ≥20 mm with either patellar tilt/translation. Binomial logistic regression identified predictors of maltracking in OSD. Optimal TT-TG distance to indicate maltracking was determined by receiver operating characteristic curve. RESULTS: 59% (101/171) of the knees with OSD showed findings of maltracking, with patella alta, trochlear dysplasia, and quadriceps tendinosis as significant predictors of maltracking (p < 0.001). Patellofemoral chondrosis was present in 63% (107/171), with maltracking contributing to higher grade chondrosis more so than increasing age (OR 8.4 versus 1.07). 13 mm was the optimal cut-off TT-TG distance to indicate maltracking (sensitivity 83%, specificity 80%). The prevalence of maltracking in the control group was 15% (p < 0.001 compared with the OSD group). CONCLUSION: Adults with sequelae of OSD are at high risk of maltracking and are likely to develop patellofemoral chondrosis. A lower threshold for identifying maltracking patients, including a lower cut-off TT-TG distance can help identify those at risk. Radiologists should maintain a high index of suspicion for maltracking in adults with OSD to guide clinical intervention.

MUSCLEMOTION: A Versatile Open Software Tool to Quantify Cardiomyocyte and Cardiac Muscle Contraction In Vitro and In Vivo.

RATIONALE: There are several methods to measure cardiomyocyte and muscle contraction, but these require customized hardware, expensive apparatus, and advanced informatics or can only be used in single experimental models. Consequently, data and techniques have been difficult to reproduce across models and laboratories, analysis is time consuming, and only specialist researchers can quantify data. OBJECTIVE: Here, we describe and validate an automated, open-source software tool (MUSCLEMOTION) adaptable for use with standard laboratory and clinical imaging equipment that enables quantitative analysis of normal cardiac contraction, disease phenotypes, and pharmacological responses. METHODS AND RESULTS: MUSCLEMOTION allowed rapid and easy measurement of movement from high-speed movies in (1) 1-dimensional in vitro models, such as isolated adult and human pluripotent stem cell-derived cardiomyocytes; (2) 2-dimensional in vitro models, such as beating cardiomyocyte monolayers or small clusters of human pluripotent stem cell-derived cardiomyocytes; (3) 3-dimensional multicellular in vitro or in vivo contractile tissues, such as cardiac "organoids," engineered heart tissues, and zebrafish and human hearts. MUSCLEMOTION was effective under different recording conditions (bright-field microscopy with simultaneous patch-clamp recording, phase contrast microscopy, and traction force microscopy). Outcomes were virtually identical to the current gold standards for contraction measurement, such as optical flow, post deflection, edge-detection systems, or manual analyses. Finally, we used the algorithm to quantify contraction in in vitro and in vivo arrhythmia models and to measure pharmacological responses. CONCLUSIONS: Using a single open-source method for processing video recordings, we obtained reliable pharmacological data and measures of cardiac disease phenotype in experimental cell, animal, and human models.

Painful type II os naviculare: introduction of a standardized, reproducible classification system.

OBJECTIVE: To provide a novel MRI classification system for the symptomatic type II os naviculare by creating a standardized grading of associated bone marrow edema (BME) and correlating with patient symptoms. METHODS: BME was classified on an ordinal scale: grade 1, faint signal immediately adjacent to the synchondrosis; grade 2, intermediate signal within the os and navicular tuberosity without extending to the navicular body; grade 3, intense signal extending to the navicular body. BME on 59 MRIs was independently graded by three radiologists. Inter- and intra-observer agreement was analyzed using intraclass correlation coefficient. Univariate and multivariate analyses assessed for patient and imaging characteristics predictive of subjective pain score. A cohort of 82 patients without BME represented a control group. RESULTS: Inter-observer agreement of BME grade was 0.95 (CI 0.93-0.97) and intra-observer was 0.92 (CI 0.87-0.96), indicating excellent agreement. In patients with BME, predictors of more severe pain were longer duration of pain (p = 0.02) and presence of soft tissue edema overlying the os naviculare (p < 0.001). One hundred percent of subjects with BME localized their pain to the medial midfoot (59/59) versus 25.6% (21/82) of controls (p < 0.001). CONCLUSIONS: This novel grading system provides reliable quantification of BME associated with os naviculare, which is a specific cause of medial foot/ankle pain. Early diagnosis is important as pain severity worsens with longer duration of symptoms. Pain severity is correlated with soft tissue edema overlying the os, which may be secondary to extrinsic compression, reactive to biomechanical stress, or reflect direct trauma.

Lung Cancer Screening Guidelines: How Readable Are Internet-Based Patient Education Resources?

OBJECTIVE: Following the findings of the National Lung Screening Trial, several national societies from multiple disciplines have endorsed the use of low-dose chest CT to screen for lung cancer. Online patient education materials are an important tool to disseminate information to the general public regarding the proven health benefits of lung cancer screening. This study aims to evaluate the reading level at which these materials related to lung cancer screening are written. MATERIALS AND METHODS: The four terms "pulmonary nodule," "radiation," "low-dose CT," and "lung cancer screening" were searched on Google, and the first 20 online resources for each term were downloaded, converted into plain text, and analyzed using 10 well-established readability scales. If the websites were not written specifically for patients, they were excluded. RESULTS: The 80 articles were written at a 12.6 ± 2.7 (mean ± SD) grade level, with grade levels ranging from 4.0 to 19.0. Of the 80 articles, 62.5% required a high school education to comprehend, and 22.6% required a college degree or higher (≥ 16th grade) to comprehend. Only 2.5% of the analyzed articles adhered to the recommendations of the National Institutes of Health and American Medical Association that patient education materials be written at a 3rd- to 7th-grade reading level. CONCLUSION: Commonly visited online lung cancer screening-related patient education materials are written at a level beyond the general patient population's ability to comprehend and may be contributing to a knowledge gap that is inhibiting patients from improving their health literacy.

Detection of unsuspected pelvic DVTs on abdominopelvic CT scans: a potentially life-saving diagnosis.

Venous thromboembolism (VTE) is a serious common disorder with substantial cost and morbidity to society and can be life threatening in some cases. The majority of VTE is diagnosed on lower extremity ultrasound or CT pulmonary angiography, but some cases of deep venous thrombosis (DVT) may be occasionally diagnosed on CT of the abdomen and pelvis by the alert radiologist. The purpose of our study was to determine the fraction of new/unsuspected DVTs diagnosed on CTAP and the subsequent management and clinical course of these patients. After Institutional Review Board approval, a retrospective search of an institutional imaging database was performed for all cases of DVTs diagnosed on CTs of the abdomen and pelvis. Patients with positive studies were further investigated via clinical chart review for their subsequent management and clinical course. The 90-day mortality of the patients diagnosed with DVT on CTAP was also recorded. Sixty-two patients met the criteria for positive DVT on CTAP. Of these 62 cases, 26 (42 %) were new. Management was substantially changed in 24 out of 26 cases (92 %), most commonly initiation of anticoagulation. The 90-day mortality rate of patients diagnosed with pelvic DVTs on CTAP in our cohort was 21 %. Timely detection of pelvic DVTs can have serious implications for patient management, morbidity, and mortality. The pelvic veins should be included in the search pattern of all radiologists who review CTs of the abdomen and pelvis.

Acoustic emissions from spin crossover complexes.

Acoustic emission from the compounds [Fe(HB(tz)3)2] and [Fe(Htrz)(trz)2]BF4 was detected during the thermally induced spin transition and is correlated with simultaneously recorded calorimetric signals. We ascribe this phenomenon to elastic waves produced by microstructural and volume changes accompanying the spin transition. Despite the perfect reversibility of the spin state switching (seen by the calorimeter), the acoustic emission activity decreases for successive thermal cycles, revealing thus irreversible microstructural evolution of the samples. The acoustic emission signal amplitude and energy probability distribution functions followed power-law behavior and the characteristic exponents were found to be similar for the two samples both on heating and cooling, indicating the universal character, which is further substantiated by the well scaled average temporal shapes of the avalanches.

An 800-year record of benthic foraminifer images and 2D morphometrics from the Santa Barbara Basin.

The Santa Barbara Basin is an extraordinary archive of environmental and ecological change, where varved sediments preserve microfossils that provide an annual to decadal record of the dynamics of surrounding ecosystems. Of the microfossils preserved in these sediments, benthic foraminifera are the most abundant seafloor-dwelling organisms. While they have been extensively utilized for geochemical and paleoceanographic work, studies of their morphology are lacking. Here we use a high-throughput imaging method (AutoMorph) designed to extract 2D data from photographic images of fossils to produce a large image and 2D shape dataset of recent benthic foraminifera from two core records sampled from the center of the Santa Barbara Basin that span an ~800-year-long interval during the Common Era (1249-2008 CE). Information on more than 36,000 objects is included, of which more than 22,000 are complete or partially-damaged benthic foraminifera. The dataset also includes other biogenic microfossils including ostracods, pteropods, diatoms, radiolarians, fish teeth, and shark dermal denticles. We describe our sample preparation, imaging, and identification techniques, and outline potential data uses.

Optimization of Inclusion Body Formation and Purification in Multi-well Plates.

Heterologous expression has long been used for the efficient production of proteins and enzymes as it offers significant advantages over purification of proteins from their native organisms. When first established, great efforts have been made to heterologously express proteins with high yields in the soluble fraction, hence, avoiding protein aggregation. In recent decades, however, it has been shown that the formation of aggregates (inclusion bodies; IBs) can be beneficial. To recover active protein, however, proteins should have been refolded from IBs after purification. The discovery that IBs themselves can also be active has revolutionized the entire protein production field. Therefore, several approaches have been described to generate catalytically active IBs during heterologous expression. Since several extrinsic and intrinsic factors such as protein structure and toxicity, pH and temperature of expression, and the used media might influence the formation of IBs, it is time and material consuming to use shake flask to examine and optimize different expression conditions. However, by using multi-well plates, it is possible to rapidly develop an efficient protocol for the expression of catalytically active IBs in a rational approach. The presented protocol was used for the heterologous expression of a 5'-adenosine monophosphate phosphorylase which forms catalytically active aggregates during expression in E. coli.

Thermodynamic Analysis of Anomalous Shape of Stress-Strain Curves for Shape Memory Alloys.

In some shape-memory single crystals the stress-strain (σ~ε) curves, belonging to stress induced martensitic transformations from austenite to martensite at fixed temperature, instead of being the usual slightly increasing function or horizontal, have an overall negative slope with sudden stress drops in it. We discuss this phenomenon by using a local equilibrium thermodynamic approach and analysing the sign of the second derivative of the difference of the Gibbs free energy. We show that, considering also the possible nucleation and growth of two martensite structural modifications/variants, the stress-strain loops can be unstable. This means that the overall slope of the uploading branch of the stress-strain curve can be negative for smooth transformation if the second martensite, which is more stable with larger transformation strain, is the final product. We also show that local stress-drops on the stress-strain curve can appear if the nucleation of the second martensite is difficult, and the presence of such local stress-drops alone can also result in an overall negative slope of the stress-strain curves. It is illustrated that the increase of the temperature of the thermal recovery during burst-like transition is a measure of the change of the nucleation energy: the more stable martensite has larger nucleation energy.

Denouement of the Energy-Amplitude and Size-Amplitude Enigma for Acoustic-Emission Investigations of Materials.

There are many systems producing crackling noise (avalanches) in materials. Temporal shapes of avalanches, U(t) (U is the detected voltage signal, t is the time), have self-similar behaviour and the normalized U(t) function (e.g., dividing both the values of U and t by S1/2, where S is the avalanche area), averaged for fixed S, should be the same, independently of the type of materials or avalanche mechanisms. However, there are experimental evidences that the temporal shapes of avalanches do not scale completely in a universal way. The self-similarity also leads to universal power-law-scaling relations, e.g., between the energy, E, and the peak amplitude, Am, or between S and Am. There are well-known enigmas, where the above exponents in acoustic emission measurements are rather close to 2 and 1, respectively, instead of E~Am3 and S~Am2, obtained from the mean field theory, MFT. We show, using a theoretically predicted averaged function for the fixed avalanche area, U(t)=atexp(-bt2) (where a and b are non-universal, material-dependent constants), that the scaling exponents can be different from the MFT values. Normalizing U by Am and t by tm (the time belonging to the Am: rise time), we obtain tm~Am1-φ (the MFT values can be obtained only if φ would be zero). Here, φ is expected to be material-independent and to be the same for the same mechanism. Using experimental results on martensitic transformations in two different shape-memory single-crystals, φ = 0.8 ± 0.1 was obtained (φ is the same for both alloys). Thus, dividing U by Am as well as t by Am1-φ (~tm) leads to the same common, normalized temporal shape for different, fixed values of S. This normalization can also be used in general for other experimental results (not only for acoustic emission), which provide information about jerky noises in materials.

Effect of Preoperative MRI Coracoid Dimensions on Postoperative Outcomes of Latarjet Treatment for Anterior Shoulder Instability.

Background: Preoperative coracoid dimensions may affect the size of the bone graft transferred to the glenoid rim and thus the postoperative outcomes of Latarjet coracoid transfer. Purpose: To determine the effect of coracoid length and width as measured on preoperative magnetic resonance imaging (MRI) on outcomes after Latarjet treatment of anterior shoulder instability. Study Design: Cohort study; Level of evidence, 3. Methods: Included were patients who underwent primary Latarjet surgery between 2009 and 2019 and had preoperative MRI scans and minimum 2-year postoperative outcomes. Longitudinal coracoid length was measured on axial MRI sequences as the distance from the coracoclavicular ligament insertion to the distal tip. Comparisons were made between shorter and longer coracoids and between narrower and wider coracoids. The outcomes of interest were recurrent instability, reoperation, complications, return to sport (RTS), and American Shoulder and Elbow Surgeons (ASES) score. Independent-samples t test, Mann-Whitney test, chi-square test, and Fisher exact test were used to compare outcomes between groups, and univariate correlation coefficients were calculated to evaluate the relationships between demographics and coracoid dimensions. Results: Overall, 56 patients were included (mean age, 28.4 years). The mean ± SD coracoid length was 21.6 ± 2.4 mm and width 10.0 ± 1.0 mm. Relative to patients with a longer coracoid (≥22 mm; n = 26), patients with a shorter coracoid (<22 mm; n = 30) had similar rates of recurrent instability (shorter vs longer; 6.7% vs 3.8%), complications (10.0% vs 15.4%), reoperation (3.3% vs 7.7%), and RTS (76.5% vs 58.8%) and similar postoperative ASES scores (85.0 vs 81.6) (P ≥ .05 for all). Likewise, relative to patients with a wider coracoid (≥10 mm; n = 27), patients with a narrower coracoid (<10 mm; n = 29) had similar prevalences of recurrent instability (narrower vs wider; 6.9% vs 3.7%), complications (17.2% vs 7.4%), reoperation (3.5% vs 7.4%), and RTS (66.7% vs 68.4%) and similar postoperative ASES scores (87.1 vs 80.0) (P ≥ .05 for all). Conclusion: Patients undergoing Latarjet coracoid transfer had similar postoperative outcomes regardless of preoperative coracoid dimensions. These findings should be confirmed in a larger cohort before further clinical recommendations are made.