Imaging of Entrapment Neuropathies in the Ankle.

Entrapment neuropathies of the ankle and foot pose a major diagnostic challenge and thus remain underdiagnosed. Recent advancements in imaging modalities, including magnetic resonance neurography (MRN), have resulted in considerable improvement in the anatomical localization and identification of pathologies leading to nerve entrapment. MRN supplements clinical examination and electrophysiologic studies in the diagnosis of neuropathies, aids in assessing disease severity, and helps formulate management strategies. A comprehensive understanding of the anatomy and imaging features of the ankle is essential to diagnose and manage entrapment neuropathies accurately. Advancements in imaging and their appropriate utilization will ultimately lead to better diagnoses and improved patient outcomes.

Individualized tibial tubercle-trochlear groove distance-to-patellar length ratio (TT-TG/PL) is a more reliable measurement than TT-TG alone for evaluating patellar instability.

PURPOSE: To evaluate the intra/inter-rater and diagnostic reliability of the sagittal plane adjusted patellar instability ratios (PIRs) compared to tibial tubercle-trochlear groove (TT-TG) distance alone while employing a matched case-control analysis for age and sex to minimize a potential confounding effect. METHODS: A retrospective case-control study was performed of all knee MRI studies of patients diagnosed with patellar instability, between 2005 and 2020 at a regional tertiary medical centre. Using a 1:1 case-control matching of sex and age at the time of the diagnosis, one control subject was assigned to each case of patellar instability. Measurements of TT-TG distance, sagittal patellar length (PL), sagittal patellar tendon length (PTL), TT-TG/PL ratio, and TT-TG/PTL ratio were conducted. Two orthopaedic surgery residents and a senior musculoskeletal radiologist were assigned to assess the intra- and inter-rater reliability. Inter-class coefficients were calculated (ICC). The receiver operating characteristic (ROC) curve and area under curve (AUC) for each parameter were compared to evaluate for diagnostic reliability. Odds ratios (OR) and their 95% confidence intervals (CI) were calculated and a multivariable logistic regression model was performed to control for possible confounders. RESULTS: The study included 324 individuals (162 case-control matched pairs). In terms of intra- and inter-rater reliability, TT-TG/PL and TT-TG/PTL ratios showed an excellent correlation within and between readers (TT-TG/PL; intra-rater ICC 0.94 and inter-rater ICC 0.92, TT-TG/PTL; intra-rater ICC 0.91 and inter-rater ICC 0.88). The ROC curve showed a slightly greater AUC of the TT-TG/PL ratio compared to TT-TG distance alone (0.75 vs 0.73, p < 0.001). When applying the pathologic cutoff of TT-TG ≥ 20 mm and TT-TG/PL ≥ 0.5; the calculated odds ratios for the above cutoff were as follows; TT-TG distance alone had an OR of 14 (95% CI 1.8-106.5, p = 0.011) and OR for TT-TG/PL ratio was 23 (95% CI 3.1-170.3, p = 0.002). In the multivariable analysis, while controlling for height and weight, only the association between TT-TG/PL ratio and patellar dislocation remained statistically significant with an adjusted OR of 2.7 (CI 1.3-5.4, p = 0.006), compared to TTTG distance alone (OR = 1.9, n.s.). CONCLUSIONS: Patellar instability ratios are significantly more reliable compared to TT-TG distance alone for the evaluation of patellar instability. Patellar instability ratios present superior diagnostic reliability, sensitivity and specificity, and intra\inter rater reliability. Thus, patellar instability ratios could function as a valuable diagnostic tool for the evaluation of patellar instability. LEVEL OF EVIDENCE: III.

Successful reconstruction of natural femoral anteversion using a short femoral stem in total hip arthroplasty surgery.

OBJECTIVE: Total hip arthroplasty (THA) involves postoperative risks, such as thigh pain, periprosthetic fractures, and stress yielding. Short, anatomical, metaphyseal-fitting, cementless femoral stems were developed to reduce these postoperative risks. This study aimed to examine the "MiniMAX" prosthesis, which is a new generation, short, anatomical femoral stem made by Medacta. METHODS: Patients underwent a low-dose computed tomography scan. Femoral anteversion was measured. We assessed the position and anteversion of the femoral component and compared them with the unoperated side. We also assessed the patients' satisfaction and functional levels at 6 months postsurgery using the Harris Hip Score (HHS) and the Oxford Hip Score (OHS). RESULTS: Nineteen individuals were recruited in this study. We found no significant difference in femoral anteversion between the operated hip and the native hip. Using the HHS and OHS questionnaires, we found clinical improvement in the 6-month postoperative scores compared with the preoperative scores. DISCUSSION: The new-generation, short, anatomical femoral stem made by Medacta is successful in reproducing natural femoral anteversion, while also improving patients' functioning and lifestyle. Future large-scale, prospective comparison trials are required to further investigate this topic.

Bone Regeneration in Load-Bearing Segmental Defects, Guided by Biomorphic, Hierarchically Structured Apatitic Scaffold.

The regeneration of load-bearing segmental bone defects remains a significant clinical problem in orthopedics, mainly due to the lack of scaffolds with composition and 3D porous structure effective in guiding and sustaining new bone formation and vascularization in large bone defects. In the present study, biomorphic calcium phosphate bone scaffolds (GreenBone™) featuring osteon-mimicking, hierarchically organized, 3D porous structure and lamellar nano-architecture were implanted in a critical cortical defect in sheep and compared with allograft. Two different types of scaffolds were tested: one made of ion-doped hydroxyapatite/ß-tricalcium-phosphate (GB-1) and other made of undoped hydroxyapatite only (GB-2). X-ray diffraction patterns of GB-1 and GB-2 confirmed that both scaffolds were made of hydroxyapatite, with a minor amount of ß-TCP in GB-1. The chemical composition analysis, obtained by ICP-OES spectrometer, highlighted the carbonation extent and the presence of small amounts of Mg and Sr as doping ions in GB-1. SEM micrographs showed the channel-like wide open porosity of the biomorphic scaffolds and the typical architecture of internal channel walls, characterized by a cell structure mimicking the natural parenchyma of the rattan wood used as a template for the scaffold fabrication. Both GB-1 and GB-2 scaffolds show very similar porosity extent and 3D organization, as also revealed by mercury intrusion porosimetry. Comparing the two scaffolds, GB-1 showed slightly higher fracture strength, as well as improved stability at the stress plateau. In comparison to allograft, at the follow-up time of 6 months, both GB-1 and GB-2 scaffolds showed higher new bone formation and quality of regenerated bone (trabecular thickness, number, and separation). In addition, higher osteoid surface (OS/BS), osteoid thickness (OS.Th), osteoblast surface (Ob.S/BS), vessels/microvessels numbers, as well as substantial osteoclast-mediated implant resorption were observed. The highest values in OS.Th and Ob. S/BS parameters were found in GB-1 scaffold. Finally, Bone Mineralization Index of new bone within scaffolds, as determined by micro-indentation, showed a significantly higher microhardness for GB-1 scaffold in comparison to GB-2. These findings suggested that the biomorphic calcium phosphate scaffolds were able to promote regeneration of load-bearing segmental bone defects in a clinically relevant scenario, which still represents one of the greatest challenges in orthopedics nowadays.

COVID-19 classification of X-ray images using deep neural networks.

OBJECTIVES: In the midst of the coronavirus disease 2019 (COVID-19) outbreak, chest X-ray (CXR) imaging is playing an important role in diagnosis and monitoring of patients with COVID-19. We propose a deep learning model for detection of COVID-19 from CXRs, as well as a tool for retrieving similar patients according to the model's results on their CXRs. For training and evaluating our model, we collected CXRs from inpatients hospitalized in four different hospitals. METHODS: In this retrospective study, 1384 frontal CXRs, of COVID-19 confirmed patients imaged between March and August 2020, and 1024 matching CXRs of non-COVID patients imaged before the pandemic, were collected and used to build a deep learning classifier for detecting patients positive for COVID-19. The classifier consists of an ensemble of pre-trained deep neural networks (DNNS), specifically, ReNet34, ReNet50¸ ReNet152, and vgg16, and is enhanced by data augmentation and lung segmentation. We further implemented a nearest-neighbors algorithm that uses DNN-based image embeddings to retrieve the images most similar to a given image. RESULTS: Our model achieved accuracy of 90.3%, (95% CI: 86.3-93.7%) specificity of 90% (95% CI: 84.3-94%), and sensitivity of 90.5% (95% CI: 85-94%) on a test dataset comprising 15% (350/2326) of the original images. The AUC of the ROC curve is 0.96 (95% CI: 0.93-0.97). CONCLUSION: We provide deep learning models, trained and evaluated on CXRs that can assist medical efforts and reduce medical staff workload in handling COVID-19. KEY POINTS: • A machine learning model was able to detect chest X-ray (CXR) images of patients tested positive for COVID-19 with accuracy and detection rate above 90%. • A tool was created for finding existing CXR images with imaging characteristics most similar to a given CXR, according to the model's image embeddings.

Scaffolds for Knee Chondral and Osteochondral Defects: Indications for Different Clinical Scenarios. A Consensus Statement.

OBJECTIVE: To develop patient-focused consensus guidelines on the indications for the use of scaffolds to address chondral and osteochondral femoral condyle lesions. DESIGN: The RAND/UCLA Appropriateness Method (RAM) was used to develop patient-specific recommendations by combining the best available scientific evidence with the collective judgement of a panel of experts guided by a core panel and multidisciplinary discussers. A list of specific clinical scenarios was produced regarding adult patients with symptomatic lesions without instability, malalignment, or meniscal deficiency. Each scenario underwent discussion and a 2-round vote on a 9-point Likert-type scale (range 1-3 "inappropriate," 4-6 "uncertain," 7-9 "appropriate"). Scores were pooled to generate expert recommendations. RESULTS: Scaffold (chondral vs. osteochondral), patient characteristics (age and sport activity level), and lesion characteristics (etiology, size, and the presence of osteoarthritis [OA]) were considered to define 144 scenarios. The use of scaffold-based procedures was considered appropriate in all cases of chondral or osteochondral lesions when joints are not affected by OA, while OA joints presented more controversial results. The analysis of the evaluated factors showed a different weight in influencing treatment appropriateness: the presence of OA influenced 58.3% of the indications, while etiology, size, and age were discriminating factors in 54.2%, 29.2%, and 16.7% of recommendations, respectively. CONCLUSIONS: The consensus identified indications still requiring investigation, but also the convergence of the experts in several scenarios defined appropriate or inappropriate, which could support decision making in the daily clinical practice, guiding the use of scaffold-based procedures for the treatment of chondral and osteochondral knee defects.

Ultrasound elastography reveals the relation between body posture and soft-tissue stiffness which is relevant to the etiology of sitting-acquired pressure ulcers.

OBJECTIVE: Sitting-acquired pressure ulcers (PUs) are common in wheelchair users. These PUs are often serious and may involve deep tissue injury (DTI). Investigating the mechanical properties of the tissues susceptible to DTI may help in guiding the prevention and early detection of PUs. In this study, shear wave elastography (SWE) was used to measure the normative mechanical properties of the soft tissues of the buttocks, i.e. skeletal muscle and subcutaneous fat, under the ischial tuberosities, in a convenient sample of healthy adults without weight bearing and with weight bearing of different times. APPROACH: We compared the stiffness properties of these soft tissues between the lying prone and sitting postures, to determine whether there are detectable property changes that may be associated with the type of posture. We hypothesized that muscle contractions and 3D tissue configurations associated with the posture may influence the measured tissue stiffnesses. MAIN RESULTS: Our results have shown that indeed, SWE values differed significantly across postures, but not over time in a specific posture or for the right versus left sides of the body. SIGNIFICANCE: We have therefore demonstrated that soft-tissue stiffness increases when sitting with weight bearing and may contribute to increasing the potential PU risk in sitting compared to lying prone, given the stiffer behavior of tissues observed in sitting postures.

Complex Osteochondral Lesions of the Talus Treated With a Novel Bi-Phasic Aragonite-based Implant.

To present initial results of a novel, bi-phasic, porous, biodegrade, and cell-free aragonite-based scaffold for treating complex osteochondral lesions of the talus (OLT). Four subjects (2 males and 2 females; 34-61 years old) were operated on their ankles due to chronic and deep OLT-Hepple grades 4 or 5 (1.8-2.2 cm2). Three subjects had OLT on the medial central trochlea, and 1 had a combined medial and lateral lesions. OLT were exposed through medial malleolus osteotomy, with an additional lateral arthrotomy in the combined lesions. Bi-phasic porous osteochondral scaffolds (single implant or 2 implants) were implanted in a press-fit manner using a designated surgical toolset. Treatment outcome was followed clinically (Foot and Ankle Outcome Score, EQ-5D 3L, Tegner activity scale) and by medical imaging (radiographs, magnetic resonance imaging) from 18 to 32 months. All Foot and Ankle Outcome Score values increased from preoperative to final follow-up values (Symptoms 62 to 71, Pain 53 to 84, ADL 60 to 89, Sport 19 to 65, and QoL 18 to 47). EQ-5D 3L increased from 0.59 to 0.76, and Tegner activity values increased from 1.5 to 3. Kellgren-Lawrence ankle radiographic scores remained stable (2 to 2). Postoperative MR evaluation demonstrated cartilage defect fill of 75% to 100% respect to the native cartilage in 3 subjects (4 OLTs), while 1 lesion was filled 25% to 50%. No graft related serious adverse events or graft failures were reported. The use of a bi-phasic osteochondral biodegradable aragonite-based scaffold in the treatment of complex OLT during the reported period presented positive and promising clinical and radiologic outcome, without serious adverse events or graft failures.

Effects of a novel medial meniscus implant on the knee compartments: imaging and biomechanical aspects.

The altered biomechanical function of the knee following partial meniscectomy results in ongoing articular cartilage overload, which may lead to progressive osteoarthritis (OA). An artificial medial meniscus implant (NUsurface® Meniscus Implant, Active Implants LLC., Memphis, TN, USA) was developed to mimic the native meniscus and may provide an effective long-term solution for OA patients, alleviate pain, and restore joint function. The goal of the current study was to investigate the potential effect of an artificial medial meniscus implant on the function of the lateral compartment of the knee and on the potential alterations in load distribution between the two compartments under static axial loading, using advanced piezo-resistive sensors. We used an integrated in situ/in vivo experimental approach combining contact pressure measurements of cadaveric knees with MRI joint space measurements of 72 mild OA patients. We employed this integrated approach to evaluate the mechanical consequences in both the medial (treated) and lateral knee compartments of two levels of meniscectomy and implantation of an artificial meniscus implant. Partial and subtotal meniscectomies of the medial meniscus resulted in statistically significant decrease in contact areas (p = 0.008 and p < 0.0001, respectively) and increased contact pressures in the medial compartment; however, implantation of the artificial meniscus implant restored the average contact pressure to 93 ± 14% of its pre-meniscectomy, intact value. Additionally, we found that neither the two different grades of medial meniscectomies, nor implantation of the artificial medial meniscus implant affected the lateral compartment of the knee. The MRI data from the patient cohort facilitated the integration of real-life clinical results together with the laboratory measurements from our cadaveric study, as these two approaches complement each other. We conclude that the use of the artificial medial meniscus implant may re-establish normal load distribution across the articulating surfaces of the medial compartment and not increase loading across the lateral knee compartment.

Sacral Soft Tissue Deformations When Using a Prophylactic Multilayer Dressing and Positioning System: MRI Studies.

PURPOSE: The sacrum is the most common location of pressure injuries (PIs) in bedridden patients. The purpose of this study was to measure the effect of specific pressure preventive devices on sacral skeletal muscle, subcutaneous fat, and skin tissue deformations. SUBJECTS AND SETTING: The sample comprised 3 healthy adults residing in a community setting in Tel Aviv, Israel. DESIGN: Descriptive, comparative design. METHODS: Tissue thickness changes of 3 healthy adults were measured using magnetic resonance imaging (MRI) in weight-bearing sacral skin, subcutaneous fat, and muscle. Changes in tissue thickness were compared under the following conditions: (1) lying supine on a rigid surface (unpadded MRI table), (2) lying on a standard foam mattress, (3) lying on a mattress after application of a prophylactic multilayer dressing, and (4) lying on a standard foam mattress with a prophylactic multilayer dressing and a positioning system. One-way analysis of variance and post hoc Tukey-Kramer multiple pairwise comparisons were used to compare outcomes. RESULTS: The mattress, the prophylactic multilayer dressing, and the turning and positioning device when applied together resulted in significantly lower deformation levels of each of the soft tissue layers (ie, skin, subcutaneous fat, and muscle separately) as well as of the total soft tissue bulk, with respect to the rigid MRI table (P < .05). CONCLUSION: Study findings suggest that a combination of preventive interventions may reduce the risk of developing a sacral PI.

Biomechanical Model for Stress Fracture-related Factors in Athletes and Soldiers.

Stress fractures (SF) are one of the most common and potentially serious overuse injuries. PURPOSE: This study aimed to develop a computational biomechanical model of strain in human tibial bone that will facilitate better understanding of the pathophysiology of SF. METHODS: The MRI of a healthy, young male was used for full anatomical segmentation of the calf tissues, which considered hard-soft tissues biomechanical interactions. From the undeformed coronal MR images, the geometry of bones, muscles, connecting ligaments, and fat were reconstructed in three dimensions and meshed to a finite element model. A force that simulated walking was applied on the tibial plateaus. The model was then analyzed for strains in the tibia under various conditions: unloaded walking, walking with a load equivalent to 30% of bodyweight, and walking under conditions of muscular fatigue. In addition, the effect of tibia robustness on strain was analyzed. RESULTS: The model showed that the tibia is mostly loaded by compression, with maximal strains detected in the distal anterior surface: 1241 and 384 microstrain, compressive and tensile, respectively. Load carriage resulted in ~30% increase in maximal effective strains. Muscle fatigue has a complex effect; fatigued calf muscles (soleus) reduced the maximal effective strains up to 9%, but fatigued thigh muscles increased those strains by up to 3%. It had also been shown that a slender tibia is substantially prone to higher maximal effective strains compared with an average (22% higher) or robust tibia (39% higher). CONCLUSIONS: Thigh muscle fatigue, load carriage, and a slender tibia were detected as factors that may contribute to the development of SF. The methodology presented here is a novel tool for investigating the pathophysiology of SF.

A multiscale modeling framework for studying the mechanobiology of sarcopenic obesity.

An inactive sedentary lifestyle is a common risk factor contributing to sarcopenic obesity. At the cell scale, sustained mechanical deformations of the plasma membrane (PM) in adipocytes, characterizing chronic static loading in weight-bearing tissues during prolonged sitting or lying, were found to promote adipogenesis. Taking a mechanobiological perspective, we correlated here the macroscale mechanical deformations of weight-bearing adipose tissues (subcutaneous and intramuscular) with mechanical strains developing in the PMs of differentiating adipocytes. An innovative multiscale modeling framework for adipose tissues was developed for this purpose, where the buttocks, adipose tissues, adipocytes and the subcellular components: intracytoplasmic nucleus and lipid droplets as well as the PMs of the cells, were all represented. We found that a positive feedback loop very likely exists and is involved in the onset and progression of sarcopenic obesity, as follows. Adipogenesis in statically deformed adipocytes results in gaining more macroscopic subcutaneous and intramuscular fat mass, which then increases fat deformations macroscopically and microscopically, and hence triggers additional adipogenesis, and so on. Our present study is highly relevant in research of sarcopenic obesity and other adipose-related diseases such as diabetes, since mechanical distortion of adipocytes promotes adipogenesis and fat gain at the different dimensional scales.

Subchondral insufficiency fracture of the knee: A recognizable associated soft tissue edema pattern and a similar distribution among men and women.

OBJECTIVE: Primary: to describe the presence and pattern of soft tissue edema in subchondral insufficiency fractures of the knee (SIFK). Secondary: to investigate the gender distribution and identify factors associated with disease progression. METHODS: MR images of 74 SIFKs in 74 patients were retrospectively reviewed for soft tissue edema presence and location, meniscal tears and extrusion and synovitis. The clinical records were reviewed for age, gender, and BMI. Follow up examinations were reviewed to assess for progression. Data were analyzed for gender distribution and for association between each imaging finding as a predictor of SIFK location and progression. RESULTS: Soft tissue edema was present in 89% (66/74) of SIFK. It was located around the MCL in 78% (58/74), posterior to and abutting on the posterior distal femur in 68% (50/74), around to the tibia in only 18% (13/74), but when present it strongly predicted the presence of a medial tibial plateau SIFK (p=5.6×10^-12). Edema extended to the vastus medialis fascia in 51% (38/74) and vastus lateralis fascia in 24% (18/74). Gender distribution was 1:1 (males=38, females=36), most common in the 6th decade (29/74, 39%). Lesion progression showed a trend towards being more common in females (8/9, 89%) compared to males (9/16, 56%), and in patients with meniscal extrusion (≥3mm) (13/14, 93%) compared to those with no extrusion (2/7, 29%). CONCLUSION: A recognizable soft tissue edema pattern is seen in SIFK and may have an important role in early diagnosis. Also, SIFK may affect equally males and females in the 6th decade and may progress more in females. Meniscal extrusion may predispose to disease progression.

The Long-Term Outcome After Varus Derotational Osteotomy for Legg-Calvé-Perthes Disease: A Mean Follow-up of 42 Years.

BACKGROUND: Varus derotational osteotomy (VDRO) is one of the most common surgical treatments for Legg-Calvé-Perthes disease, yet its long-term results have not been fully assessed. We aimed to determine the long-term clinical and radiographic outcomes following VDRO. METHODS: Forty patients (43 hips) who underwent VDRO for Legg-Calvé-Perthes disease at our institution from 1959 to 1983, and participated in a follow-up study completed 10 years earlier, were approached for the present study. Clinical examination and radiographs were evaluated. Hip status and well-being were assessed with the Harris hip score and the Short Form-36 (SF-36). RESULTS: Thirty-five patients (37 hips) participated in the study. Information regarding the need for an arthroplasty was gathered on 4 additional hips from the previous study. The mean follow-up was 42.5 years (range, 32.4 to 56.5 years), with a mean patient age of 50.2 years (range, 35.9 to 67.8 years). In total, 7 patients (7 hips; 17% of 41 hips for which information was available, including 1 hip from the original cohort of 40 patients [43 hips]), underwent a total hip arthroplasty for hip pain. Excluding patients who had undergone an arthroplasty, the mean Harris hip and SF-36 scores were 79.8 points (range, 23.1 to 100 points) and 74.8 (range, 15.1 to 100), respectively. Twenty (64.5%) of the 31 hips that had not been replaced achieved a good or excellent Harris hip score (≥80 points). Sixteen (57.1%) of 28 hips with follow-up radiographs had no, or minimal, signs of osteoarthritis. The Stulberg classification was associated with the Harris hip score, the SF-36 score, hip pain, a Trendelenburg sign, coxa magna, and the Tönnis grade. In a multivariate analysis, the Stulberg classification was the only factor associated with fair or poor outcomes (a Harris hip score of <80 points). Patients with a Stulberg class-III or IV hip had significant deterioration with respect to the Harris hip score and Tönnis grade during the 10-year period since the last follow-up. CONCLUSIONS: A long-term follow-up of patients who were operatively treated for Legg-Calvé-Perthes disease revealed that a low proportion underwent total hip arthroplasty and a relatively high proportion maintained good clinical and radiographic outcomes. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The inter-observer variability of breast density scoring between mammography technologists and breast radiologists and its effect on the rate of adjuvant ultrasound.

PURPOSE: This study assesses the inter-observer variability of mammographic breast density scoring (BDS) between technologists and radiologists and evaluates the effect of technologist patient referral on the load of adjuvant ultrasounds. MATERIALS AND METHODS: In this IRB approved study, a retrospective analysis of 503 prospectively acquired, random mammograms was performed between January and March 2014. Each mammogram was evaluated for BDS independently and blindly by both the performing technologist and the interpreting radiologist. Statistical calculation of the Spearman correlation coefficient and weighted kappa were obtained to evaluate the inter-observer variability between technologists and radiologists and to examine whether it relates to the technologist's seniority or women's age. The effect on the load of adjuvant ultrasounds was evaluated. RESULTS: 10 mammography technologists and 7 breast radiologists participated in this study. BDS agreement levels between technologists and radiologists were in the fair to moderate range (kappa values: 0.3-0.45, Spearman coefficient values: 0.59-0.65). The technologists markedly over-graded the density compared to the radiologists in all the subsets evaluated. Comparison between low and high-density groups demonstrated a similar trend of over-grading by technologists, who graded 51% of the women as having dense breasts (scores 3-4) compared to 27% of the women graded as such by the radiologists. This trend of over grading breast density by technologists was unrelated to the women's age or to the technologists' seniority. CONCLUSION: Mammography technologists over-grade breast density. Technologists' referral to an adjuvant ultrasound leads to redundant ultrasound studies, unnecessary breast biopsies, costs and increased patient anxiety.

Bone marrow lesions and subchondral bone pathology of the knee.

Bone marrow lesions (BMLs) around the knee are a common magnetic resonance imaging (MRI) finding. However, despite the growing interest on BMLs in multiple pathological conditions, they remain controversial not only for the still unknown role in the etiopathological processes, but also in terms of clinical impact and treatment. The differential diagnosis includes a wide range of conditions: traumatic contusion and fractures, cyst formation and erosions, hematopoietic and infiltrated marrow, developmental chondroses, disuse and overuse, transient bone marrow oedema syndrome and, lastly, subchondral insufficiency fractures and true osteonecrosis. Regardless the heterogeneous spectrum of these pathologies, a key factor for patient management is the distinction between reversible and irreversible conditions. To this regard, MRI plays a major role, leading to the correct diagnosis based on recognizable typical patterns that have to be considered together with coexistent abnormalities, age, and clinical history. Several treatment options have been proposed, from conservative to surgical approaches. In this manuscript the main lesion patterns and their management have been analysed to provide the most updated evidence for the differential diagnosis and the most effective treatment.

Load distribution in early osteoarthritis.

Total knee replacement is an accepted standard of care for the treatment of advanced knee osteoarthritis with good results in the vast majority of older patients. The use in younger and more active populations, however, remains controversial due to concerns over activity restrictions, implant survival, and patient satisfaction with the procedure. It is in these younger patient populations that alternatives to arthroplasty are increasingly being explored. Historically, osteotomy was utilized to address unicompartmental pain from degeneration and overload, for example, after meniscectomy. Utilization rates of osteotomy have fallen in recent years due to the increasing popularity of partial and total knee arthroplasty. This article explores the indications and outcomes of traditional unloading osteotomy, as well as newer options that are less invasive and offer faster return to function.

The role of meniscal tissue in joint protection in early osteoarthritis.

It is widely accepted that partial meniscectomy leads to early onset of osteoarthritis (OA). A strong correlation exists between the amount and location of the resected meniscus and the development of degenerative changes in the knee. On the other hand, osteoarthritic changes of the joint alter the structural and functional integrity of meniscal tissue. These alterations might additionally compromise the limited healing capacity of the meniscus. In young, active patients without cartilage damage, meniscus therapy including partial meniscectomy, meniscus suture, and meniscus replacement has proven beneficial effects in long-term studies. Even in an early osteoarthritic milieu, there is a relevant regenerative potential of the meniscus and the surrounding cartilage. This potential should be taken into account, and meniscal surgery can be performed with the correct timing and the proper indication even in the presence of early OA.

Aetiology and pathogenesis of bone marrow lesions and osteonecrosis of the knee.

Bone marrow lesions (BML) of the knee are a frequent MRI finding, present in many different pathologies including trauma, post-cartilage surgery, osteoarthritis, transient BML syndromes, spontaneous insufficiency fractures, and true osteonecrosis.Osteonecrosis (ON) is in turn divided into spontaneous osteonecrosis (SONK), which is considered to be correlated to subchondral insufficiency fractures (SIFK), and avascular necrosis (AVN) which is mainly ascribable to ischaemic events.Every condition has a MRI pattern, a different clinical presentation, and specific histological features which are important in the differential diagnosis.The current evidence supports an overall correlation between BML and patient symptoms, although literature findings are variable, and very little is known about the natural history and the progression of these lesions.A full understanding of BML will be mandatory in the future to better address the different pathologies and develop appropriately-targeted treatments. Cite this article: Marcacci M, Andriolo L, Kon E, Shabshin N, Filardo G. Aetiology and pathogenesis of bone marrow lesions and osteonecrosis of the knee. EFORT Open Rev 2016;1:219-224. DOI: 10.1302/2058-5241.1.000044.

The effect of mechanical strains in soft tissues of the shoulder during load carriage.

Soldiers and recreational backpackers are often required to carry heavy loads during military operations or hiking. Shoulder strain appears to be one of the limiting factors of load carriage due to skin and underlying soft tissue deformations, trapped nerves, or obstruction of blood vessels. The present study was aimed to determine relationships between backpack weights and the state of loads in the shoulder׳s inner tissues, with a special focus on the deformations in the brachial plexus. Open-MRI scans were used for developing and then verifying a three-dimensional, non-linear, large deformation, finite element model of the shoulder. Loads were applied at the strap-shoulder contact surfaces of the model by pulling the strap towards the shoulder until the desired load was reached. Increasing the strap tensile forces up to a load that represents 35kg backpack resulted in gradual increase in strains within the underlying soft tissues: the maximal tensile strain in the brachial plexus for a 25kg backpack was 12%, and while carrying 35kg, the maximal tensile strain increased to 16%. The lateral aspect of the brachial plexus was found to be more vulnerable to deformation-inflicted effects than the medial aspect. This is due to the anatomy of the clavicle that poorly shields the plexus from compressive loads applied during load carriage, while the neural tissue in the medial aspect of the shoulder is better protected by the clavicle. The newly developed model can serve as a tool to estimate soft tissue deformations in the brachial plexus for heavy backpack loads, up to 35kg. This method will allow further development of new strap structures and materials for alleviating the strains applied on the shoulder soft tissues.