To present an overview of the current role of imaging in clinical trials of knee osteoarthritis (OA), focusing on radiography and magnetic resonance imaging (MRI) in the context of their role as both inclusion criteria and structural outcome measures. A non-systematic literature search (PubMed) was performed, starting with a list of terms including the title of the current manuscript, followed by multiple search terms. The identified methodologies, findings, concepts, and recommendations were organized into a systematic framework, providing an overview of the current and future role of imaging in OA clinical trials. Conventional radiography is the most commonly used modality for the evaluation of OA in clinical trials of disease-modifying OA drugs (DMOADs). Radiography is used to define the severity of structural disease and to measure joint space width as an inclusionary criterion, and has also been employed as an outcome measure. Limitations include a lack of reproducibility, a lack of sensitivity, specificity, and responsiveness regarding structural progression, and an insufficient ability to depict diagnoses of exclusion. MRI is more sensitive and specific in assessing tissue damage and its progression. Using abbreviated imaging protocols and rapid image assessment, MRI may be applied at screening. Quantitative and semiquantitative approaches have been commonly used as outcome measures, and both have advantages and disadvantages. Reasons for the failure of past DMOAD trials are multifold and include patient selection based on imaging and application of imaging outcome measures that are either not sufficiently sensitive to change or are difficult to reliably reproduce longitudinally.

Nerve growth factor (a-NGF) inhibitors have been developed for pain treatment including symptomatic osteoarthritis (OA) and have proven analgesic efficacy and improvement in functional outcomes in patients with OA. However, despite initial promising data, a-NGF clinical trials focusing on OA treatment had been suspended in 2010. Reasons were based on concerns regarding accelerated OA progression but were resumed in 2015 including detailed safety mitigation based on imaging. In 2021, an FDA advisory committee voted against approving tanezumab (one of the a-NGF compounds being evaluated) and declared that the risk evaluation and mitigation strategy was not sufficient to mitigate potential safety risks. Future clinical trials evaluating the efficacy of a-NGF or comparable molecules will need to define strict eligibility criteria and will have to include strategies to monitor safety closely. While disease-modifying effects are not the focus of a-NGF treatments, imaging plays an important role to evaluate eligibility of potential participants and to monitor safety during the course of these studies. Aim is to identify subjects with on-going safety findings at the time of inclusion, define those potential participants that are at increased risk for accelerated OA progression and to withdraw subjects from on-going studies in a timely fashion that exhibit imaging-confirmed structural safety events such as rapid progressive OA. OA efficacy- and a-NGF studies apply imaging for different purposes. In OA efficacy trials image acquisition and evaluation aims at maximizing sensitivity in order to capture structural effects between treated and non-treated participants in longitudinal fashion. In contrast, the aim of imaging in a-NGF trials is to enable detection of structural tissue alterations that either increase the risk of a negative outcome (eligibility) or may result in termination of treatment (safety).

Running is an increasingly popular sport and form of exercise. Because of the importance of the hip in the biomechanics involved with running, forming the primary connection between the axial and appendicular skeleton of the lower extremities, accurate diagnosis and reporting of hip pathology are vital for appropriate management. This review provides an overview of the most common hip pathologies and injuries encountered in runners. Radiologic studies, primarily conventional radiography and magnetic resonance imaging (MRI) provide useful diagnostic information and should be used in combination with clinical findings to help guide therapeutic management.

Intra-articular masses are not a rare finding in routine imaging. This is particularly true in patients with underlying joint diseases such as degenerative arthritis. Nevertheless, concomitant presentation is rather uncommon in imaging studies. The authors report an unusual concomitant lipoma arborescens and synovial osteochondromatosis (which has not previously been reported in the literature to the best of the authors’ knowledge) in a man in his 60 s with a long-standing history of knee osteoarthritis. In this case presentation, we review the differential diagnosis for noninfectious synovial proliferative disorders presenting as intra-articular masses, their potential association with underlying joint pathology, and discuss the key imaging features and appropriate treatment.

As the largest rotator cuff muscle, the subscapularis plays a major role in stabilizing the glenohumeral joint, in conjunction with surrounding rotator cuff structures. Injury to the subscapularis tendon can be isolated, but more commonly is seen in conjunction with supraspinatus tendon pathology. Injury can be associated with biceps pulley instability, superior labral anterior-posterior (SLAP) tears, humeral head subluxation, and anterosuperior and coracoid impingements. The involvement of the rotator interval can lead to what is called “the hidden lesion,” due to its difficulty to diagnose during arthroscopy. Understanding the anatomical relations of the subscapularis tendon with the rest of the rotator cuff and rotator interval, as well as common patterns of injury that involve the subscapularis tendon, can aid in proper diagnosis of these injuries leading to prompt surgical repair. This review describes the anatomy of the subscapularis muscle and tendon, and the magnetic resonance imaging (MRI) patterns of subscapularis tendon injury.

Objective:Describe the radiograph-based screening program and frequencies of ineligibility in 3 large, international, randomized, double-blind, phase 3 studies of subcutaneous tanezumab in patients with osteoarthritis (OA). Design:Standardized bilateral shoulder, hip, and knee screening radiographs were obtained by trained imaging technologists and centrally read by 1 of 5 musculoskeletal radiology experts trained using a program-specific imaging atlas. Inter-reader consistency was tracked with test cases blindly inserted into the reader queue. Readers attended quarterly calibration meetings. Protocol-specified radiographic exclusion criteria included rapidly progressive OA (RPOA) or risk factors for RPOA (including severe malalignment of the knee, subchondral insufficiency fracture, atrophic OA, and osteonecrosis). Patients reporting disproportionate pain to radiographic evidence of OA in the hip or knee (without other pathology) were ineligible under a nonradiographic exclusion criterion. Results:At >480 international sites, 23,079 patients entered screening and 13,797 were radiographically assessed. Across 6 sets of quarterly testing, pairwise central reader agreement on radiographic eligibility was 72-87% (kappa: 0.41-0.71) and on radiographic OA grading 77-84% (kappa: 0.68-0.75). Among the 5,773/13,797 (41.8%) patients who met exclusionary criteria, 27% had disproportionate pain to radiographic findings (~10% of knee/hip radiographs). RPOA or risk factors for RPOA were each identified in <5% of patients (usually 1 joint) and <3% of knee/hip/shoulders. Conclusions:The phase 3 tanezumab screening program demonstrated the utility of radiographs to screen patients entering NGF inhibitor trials. A high degree of reader concordance was achieved. RPOA and risk factors for RPOA were not commonly observed. NCT02697773, NCT02709486, NCT02528188.

HomeRadiologyVol. 294, No. 3 PreviousNext CommunicationsFree AccessLetters to the EditorSafety of Intra-articular Corticosteroid InjectionMatthew Jiang*,† , Keith Lim*,†, Mandana Nikpour‡Matthew Jiang*,† , Keith Lim*,†, Mandana Nikpour‡Author AffiliationsOsteoarthritis Hip and Knee Service (OAHKS), St Vincent’s Hospital, Melbourne, Australia*Department of Rheumatology, Western Health, 160 Gordon St, Footscray, VIC 3011, Australia†University of Melbourne, St Vincent’s Hospital, Melbourne, Australia‡e-mail: [email protected]Matthew Jiang*,† Keith Lim*,†Mandana Nikpour‡Published Online:Jan 14 2020https://doi.org/10.1148/radiol.2020192552MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Editor:We read with great interest the article by Dr Kompel and colleagues in the December 2019 issue of Radiology (1). The authors investigated adverse events in a retrospective cohort of patients with hip and knee osteoarthritis (OA) who received US-guided intra-articular corticosteroid (IACS) injections. A number of complications were observed, including accelerated OA progression, subchondral insufficiency fractures, and osteonecrosis.We appreciate the work of Kompel et al because it draws attention to potential adverse effects of these procedures; however, there are several issues that led us to interpret these findings with caution.First, there was no assessment of confounding factors that may contribute to the risk of observed complications. For example, weight, age, and sex influence the progression of OA (2,3). Systemic corticosteroids and diabetes contribute to the risk of avascular necrosis, and osteoporosis risk must be considered in patients who develop insufficiency fractures. Second, in the absence of a control group or comparison to general population risk, we cannot reliably interpret the reported risk of these complications.Finally, there is substantial inconsistency in the use of imaging in this cohort. It is not clear what proportion of patients underwent baseline imaging or the chronologic relationship to the IACS. Almost half of the patients (218 of 459) did not undergo follow-up imaging. Given that the most commonly observed complication was rapid progression of OA, the missing radiologic data make it difficult to interpret these quantified risks.In our experience as a multidisciplinary OA service providing rheumatologist and allied health–based care to patients with knee and hip OA (4), IACS injections provide an often-beneficial symptomatic treatment for patients in whom there are limited other effective options for nonsurgical management. Although we acknowledge that these data are presented in an illustrative fashion, the limitations discussed above make it difficult to draw clear conclusions about the association or causative relationship between these complications and the use of IACS injection. Further controlled prospective studies are required to investigate this and define characteristics of patients in whom the benefit-to-risk ratio of IACS injection is favorable, informing more appropriate use.Disclosures of Conflicts of Interest: M.J. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: disclosed no relevant relationships. Other relationships: holds an NHMRC Career Development Fellowship (APP1126370). K.L. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: received money for consultancy from Union Chimique Belge. Other relationships: disclosed no relevant relationships. M.N. disclosed no relevant relationships.References1. Kompel AJ, Roemer FW, Murakami AM, Diaz LE, Crema MD, Guermazi A. Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought? Radiology 2019;293(3):656–663. Link, Google Scholar2. Srikanth VK, Fryer JL, Zhai G, Winzenberg TM, Hosmer D, Jones G. A meta-analysis of sex differences prevalence, incidence and severity of osteoarthritis. Osteoarthritis Cartilage 2005;13(9):769–781. Crossref, Medline, Google Scholar3. Zheng H, Chen C. Body mass index and risk of knee osteoarthritis: systematic review and meta-analysis of prospective studies. BMJ Open 2015;5(12):e007568. Crossref, Medline, Google Scholar4. Dabare C, Le Marshall K, Leung A, Page CJ, Choong PF, Lim KK. Differences in presentation, progression and rates of arthroplasty between hip and knee osteoarthritis: Observations from an osteoarthritis cohort study—a clear role for conservative management. Int J Rheum Dis 2017;20(10):1350–1360. Crossref, Medline, Google ScholarReferences1. Kompel AJ, Roemer FW, Murakami AM, Diaz LE, Crema MD, Guermazi A. Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought? Radiology 2019;293(3):656–663. Link, Google Scholar2. Roemer FW, Hayes CW, Miller CG, Hoover K, Guermazi A. Imaging atlas for eligibility and on-study safety of potential knee adverse events in anti-NGF studies (Part 1). Osteoarthritis Cartilage 2015;23(Suppl 1):S22–S42. Crossref, Medline, Google Scholar3. Roemer FW, Hayes CW, Miller CG, Hoover K, Guermazi A. Imaging atlas for eligibility and on-study safety of potential hip adverse events in anti-NGF studies (Part 2). Osteoarthritis Cartilage 2015;23(Suppl 1):S43–S58. Crossref, Medline, Google Scholar4. McAlindon TE, LaValley MP, Harvey WF, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: A randomized clinical trial. JAMA 2017;317(19):1967–1975. Crossref, Medline, Google ScholarReferences1. Kompel AJ, Roemer FW, Murakami AM, Diaz LE, Crema MD, Guermazi A. Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought? Radiology 2019;293(3):656–663. Link, Google Scholar2. Srikanth VK, Fryer JL, Zhai G, Winzenberg TM, Hosmer D, Jones G. A meta-analysis of sex differences prevalence, incidence and severity of osteoarthritis. Osteoarthritis Cartilage 2005;13(9):769–781. Crossref, Medline, Google Scholar3. Zheng H, Chen C. Body mass index and risk of knee osteoarthritis: systematic review and meta-analysis of prospective studies. BMJ Open 2015;5(12):e007568. Crossref, Medline, Google Scholar4. Dabare C, Le Marshall K, Leung A, Page CJ, Choong PF, Lim KK. Differences in presentation, progression and rates of arthroplasty between hip and knee osteoarthritis: Observations from an osteoarthritis cohort study—a clear role for conservative management. Int J Rheum Dis 2017;20(10):1350–1360. Crossref, Medline, Google ScholarResponseAli Guermazi*,† , Andrew J. Kompel*, Akira M. Murakami*, Luis E. Diaz*,†, Michel D. Crema*,‡, Frank W. Roemer*,§Ali Guermazi*,† , Andrew J. Kompel*, Akira M. Murakami*, Luis E. Diaz*,†, Michel D. Crema*,‡, Frank W. Roemer*,§Author AffiliationsDepartment of Radiology, Boston University School of Medicine, 820 Harrison Ave, FGH Building, 3rd Floor, Boston, MA 02118*Department of Radiology, Veterans Affairs Hospital, Boston, Mass†Institute of Sports Imaging, French National Institute of Sports (INSEP), Paris, France‡Department of Radiology, Friedrich-Alexander University Erlangen-Nürnberg (FAU) and University Hospital Erlangen, Erlangen, Germany§e-mail: [email protected]We read with great interest the concerns related to our article (1). We fully agree that the data presented in our report may be challenging to interpret as we did not present the results of a research study but rather a collection of cases and findings we observed in our daily practice. The purpose of this special report was to draw the attention of the medical community, the stakeholders, and the patients to the possible risks and complications of IACS injection. We focused on potential complications after IACS injections of the hip and knee in 2018 at a single institution. We acknowledge that we did not adjust for any confounding factors, nor did we include a control group. The findings were presented in an illustrative fashion, and we supported our observations with the numbers that were available.We acknowledged that we did not systematically follow up every patient as this was not designed as a prospective study or a randomized clinical trial. Thus, the mentioned substantial inconsistency in the use of imaging in this cohort is inherent to the purely observational nature of this study. On the other hand, all patients reported in the study had baseline images with radiographs of the hip or knee at least and rarely MRI. Almost half of the patients did not have follow-up images available. Most of the patients underwent joint replacement (which may be secondary to IACS injection complications in some cases), and some were lost to follow-up. As such, we think that the reported complications are likely to be underestimated in our report.Dr Jiang and colleagues suggest that, given that the most commonly observed complication was RPOA, the missing radiologic data make it difficult to interpret these quantified risks. The cases we presented as RPOA were defined as either RPOA type 1 or RPOA type 2. For both diagnoses, at least two consecutive radiographs within 1 year are necessary, as was the case in our series. RPOA type 1 is defined as the loss of 2 mm or more of the joint space width within no more than a year (2). RPOA type 2 is defined as rapid articular destruction with accelerated bone loss not typically seen in patients with OA within a previously normally appearing joint—also within a 1-year period or sooner (3).While in individual cases IACS may have a temporary beneficial effect, we refer to the American College of Rheumatology and the Osteoarthritis Research Society guidelines, which conditionally recommend IACS injections in the treatment of patients with OA. The American Academy of Orthopedic Surgeons, conversely, does not currently recommend IACS injections because the benefit is either temporary or nonexistent. In addition, McAlindon et al (4) in their double-blinded randomized clinical trial clearly showed that patients with symptomatic knee OA and intra-articular injection of triamcinolone lost significantly more cartilage volume compared with patients who received intra-articular saline injections. No significant differences in knee pain were observed, leading McAlindon et al to conclude that the findings do not support this treatment for patients with symptomatic knee OA (4).We agree that conclusions on causality cannot be drawn based solely on our data. This is why we have tried to raise awareness of this topic and why we stated that “the radiologic community should actively engage in high-quality research on this topic to better understand potential at-risk conditions prior to intervention and to better understand potential adverse joint events after these procedures to avoid possible complications” (1). Disclosures of Conflicts of Interest: A.G. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: is a paid consultant for TissueGene, MerckSerono, Pfizer, AstraZeneca, Galapagos, and Roche; is a shareholder of Boston Imaging Core Laboratory. Other relationships: disclosed no relevant relationships. A.J.K. disclosed no relevant relationships. A.M.M. disclosed no relevant relationships. L.E.D. disclosed no relevant relationships. M.D.C. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: is a shareholder in Boston Imaging Core Laboratory. Other relationships: disclosed no relevant relationships. F.W.R. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: is a shareholder in Boston Imaging Core Laboratory. Other relationships: disclosed no relevant relationships.References1. Kompel AJ, Roemer FW, Murakami AM, Diaz LE, Crema MD, Guermazi A. Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought? Radiology 2019;293(3):656–663. Link, Google Scholar2. Roemer FW, Hayes CW, Miller CG, Hoover K, Guermazi A. Imaging atlas for eligibility and on-study safety of potential knee adverse events in anti-NGF studies (Part 1). Osteoarthritis Cartilage 2015;23(Suppl 1):S22–S42. Crossref, Medline, Google Scholar3. Roemer FW, Hayes CW, Miller CG, Hoover K, Guermazi A. Imaging atlas for eligibility and on-study safety of potential hip adverse events in anti-NGF studies (Part 2). Osteoarthritis Cartilage 2015;23(Suppl 1):S43–S58. Crossref, Medline, Google Scholar4. McAlindon TE, LaValley MP, Harvey WF, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: A randomized clinical trial. JAMA 2017;317(19):1967–1975. Crossref, Medline, Google ScholarArticle HistoryPublished online: Jan 14 2020Published in print: Mar 2020 FiguresReferencesRelatedDetailsCited ByComparing the Risk of Osteonecrosis of the Femoral Head Following Intra-Articular Corticosteroid and Hyaluronic Acid InjectionsNathan H.Varady, Paul F.Abraham, Michael P.Kucharik, David M.Freccero, Eric L.Smith, Scott D.Martin2022 | Journal of Bone and Joint Surgery, Vol. 104, No. 12Recommended Articles Risks and Benefits of Intra-articular Corticosteroid Injection for Treatment of Osteoarthritis: What Radiologists and Patients Need to KnowRadiology2019Volume: 293Issue: 3pp. 664-665Intra-articular Corticosteroid Injections for the Treatment of Hip and Knee Osteoarthritis-related Pain: Considerations and Controversies with a Focus on Imaging—Radiology Scientific Expert PanelRadiology2020Volume: 297Issue: 3pp. 503-512Intra-articular Corticosteroid Injections in the Hip and Knee: Perhaps Not as Safe as We Thought?Radiology2019Volume: 293Issue: 3pp. 656-663The Safety and Potential Harm of Intraarticular Steroid Injections: The Debate ContinuesRadiology2022Volume: 304Issue: 2pp. 370-371Intraarticular Steroid Injection in Hip and Knee with Fluoroscopic Guidance: Reassessing SafetyRadiology2022Volume: 304Issue: 2pp. 363-369See More RSNA Education Exhibits Musculoskeletal Manifestations of Systemic Lupus Erythematosus: An Imaging OverviewDigital Posters2022Subchondral Stress Injuries: What’s to Blame? 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Osteoarthritis (OA) of the hip and knee is among the most common joint disorders. Intra-articular corticosteroid (IACS) injections are frequently performed to treat OA and other joint-related pain syndromes; however, there is conflicting evidence on their potential benefit. There is a lack of prospective and large retrospective studies evaluating potential joint findings, including increased risk for accelerated OA progression or adverse joint events, after treatment with IACS injection. Four main adverse joint findings have been structurally observed in patients after IACS injections: accelerated OA progression, subchondral insufficiency fracture, complications of osteonecrosis, and rapid joint destruction, including bone loss. Physicians, including radiologists, should be familiar with imaging findings and patient characteristics that may help them identify potential joints at risk for such events. The purpose of this report is to review the existing literature, describe observed adverse joint events after IACS injections, and provide an outlook on how this may affect clinical practice. Additional research endeavors are urgently needed to better understand and identify risk factors prior to intervention and to detect adverse joint events after injection as early as possible to prevent or minimize complications.

Osteoarthritis (OA) of the hip and knee is among the most common joint disorders. Infra-articular corticosteroid (MC'S) injections are frequently performed to treat OA and other joint-related pain syndromes; however, there is conflicting evidence on their potential benefit. There is a lack of prospective and large retrospective studies evaluating potential joint findings, including increased risk for accelerated OA progression or adverse joint events, after treetment with IACS injection. Four main adverse joint findings have been structurally observed in patients after IACS injections: accelerated OA progression, subchondral insufficiency fracture, complications of osteonecrosis, and rapid joint destruction, including bone loss. Physicians, including radiologists, should be familiar with imaging findings and patient characteristics that may help them identify potential joints at risk for such events. The purpose of this re-port is to review the existing literature, describe observed adverse joint events after IACS injections, and provide an outlook on how this may affect clinical practice. Additional research endeavors are urgently needed to better understand and identify risk factors prior to intervention and to detect adverse joint events after injection as early as possible to prevent or minimize complications. (C) RSNA. 2019

Peripatellar fat pads are intracapsular extrasynovial adipose cushions that accommodate the changing shape and volume of articular spaces during movement. Variations in bone geometry, passive and active stabilization mechanisms and/or functional demands may lead to peripatellar fat pad abnormalities. While peripatellar fat pads may be affected a variety of conditions such as synovial inflammation, tumor and fibrosis, a mechanical origin should also be considered. Commonly, the clinical term “impingement” is used synonymously in the radiological literature to refer to three distinct entities of structural peripatellar fat pad abnormalities: superolateral the infrapatellar fat pad (Hoffa fat pad) edema, suprapatellar fat pad edema, and prepatellar fat pad edema, implying a mechanical origin of these conditions. The aim of this pictorial review is to describe the normal anatomy of the extensor mechanism of the knee, and discuss the relation of patellofemoral maltracking to the above-mentioned peripatellar fat pad conditions based on current evidence.

Patellar fractures account for approximately 1% of all skeletal fractures and may result from direct, indirect, or combined trauma. Because of the importance of patellar integrity for knee extension and the risk of associated injury to the extensor mechanism, accurate reporting and description of fracture type is paramount for appropriate management. This pictorial essay aims to review the normal anatomy of the patella, the mechanisms of injury and different types of patellar fractures, with a brief introduction to therapeutic management. Teaching Points • Patellar fractures are classified according to their morphology and degree of displacement.• Direct trauma results in stellate fractures.• Indirect trauma results in transverse fractures.• Displacement should raise suspicion for retinacular injury.

OBJECTIVE:Nerve growth factor antibodies (NGF-ab) have shown promising analgesic efficacy. Aim was to describe reader training efforts and present reliability data focusing on radiographic eligibility in the tanezumab program. METHODS:A multi-step process was used for reader calibration and reliability testing. First, a reference standard set of cases was created and diagnostic performance was evaluated. A second exercise focused on agreement of ordinal assessment (Kellgren-Lawrence grading) of radiographic osteoarthritis. Subsequently, 11 readers were trained and read a test set of 100 cases focused on eligibility assessments. Additional reliability testing and calibration of five core readers assessing eligibility of 30 cases was performed 3 and 6 months after study start. RESULTS:Sensitivity for the reference standard readings ranged from 0.50 to 0.90 and specificity from 0.40 to 0.83. Overall agreement for Kellgren-Lawrence grading ranged from 71.4% to 82.9%. For the 11 reader exercise, in 76% of cases at least 8 of 11 readers agreed on eligibility status. For the reliability testing 3 months after study start, in 80.0% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.43 (95% CI: 0.32-0.54). For the reliability testing after 6 months, in 83.3% of cases at least 4 of 5 readers agreed on eligibility with a κ = 0.52 (95% CI: 0.41-0.63). CONCLUSIONS:After intense efforts spent in the development of an imaging program for an NGF-ab clinical program, the achieved reliability for eligibility assessment is substantial but not perfect. Ongoing efforts of calibration prior to including additional readers to the program and during study conduct between current readers will be needed to ensure agreement on potential adverse events and radiographic disease severity.

Scapholunate advanced collapse (SLAC) is the most common cause of osteoarthritis involving the wrist. Along with clinical investigation, radiological studies play a vital role in the diagnosis of SLAC wrist. Given that the osteoarthritic changes that are seen with SLAC occur in a predictable progressive pattern, it is important to understand the pathological evolution of SLAC to be able to recognise the associated progressive imaging findings seen with this disease process. Focusing on radiological findings, this article provides a pictorial review of the anatomy of the scapholunate interosseous ligament as well as the common terminology and biomechanical alterations seen in the pathway leading to the development of SLAC arthropathy. We will then discuss two additional common causes of SLAC wrist and their imaging findings, namely scaphoid non-union advanced collapse and calcium pyrophosphate dehydrate disease. In addition, we will provide a brief overview of the current treatment options of these pathological entities.

Radiographically occult and subtle fractures are a diagnostic challenge. They may be divided into (1) "high energy trauma fracture," (2) "fatigue fracture" from cyclical and sustained mechanical stress, and (3) "insufficiency fracture" occurring in weakened bone (e.g., in osteoporosis and postradiotherapy). Independently of the cause, the initial radiographic examination can be negative either because the findings seem normal or are too subtle. Early detection of these fractures is crucial to explain the patient's symptoms and prevent further complications. Advanced imaging tools such as computed tomography, magnetic resonance imaging, and scintigraphy are highly valuable in this context. Our aim is to raise the awareness of radiologists and clinicians in these cases by presenting illustrative cases and a discussion of the relevant literature.

Sesamoids and accessory ossicles seen in the foot vary widely in their prevalence and appearance. Occasionally, these bones may be associated with painful syndromes, due to various pathologies, including trauma, infection, inflammation, degeneration and others. However, symptomatic accessory and sesamoid bones are rare, and search for additional pathology should be performed. Although the clinical significance of these osseous structures is probably minor, clinicians very commonly ask about these bones, which may originate an unnecessary work-up. Therefore, knowledge of their presence and morphological variations is important to prevent misinterpreting them as fractures-a common error. Finally, it may be very difficult to distinguish between incidental variants and truly symptomatic ones. Radiological studies provide insight regarding the presence and pathology involving these bones. This review describes an overview of the anatomy of sesamoids and accessory ossicles in the foot, and provides a pictorial review of their pathological conditions, including trauma, sesamoiditis, osteomyelitis, osteoarthritis and pain syndromes. Radiological studies including radiography, ultrasound, scintigraphy, computed tomography (CT) and magnetic resonance imaging (MRI) provide useful information which should be used in concert with clinical findings to guide patient management. Teaching points • Sesamoids and accessory ossicles seen in the foot vary widely in their prevalence and appearance. • Pathology of these bones includes trauma, sesamoiditis, infection, osteoarthritis and pain syndromes. • Radiography, ultrasound, scintigraphy, CT and MRI provide information regarding the pathology of these bones.

Background Appilication of MR imaging to diagnose Adhesive Capsulitis (AC) has previously been described. However, there is insufficient information available for the MRI analysis of AC. This study is to describe and evaluate the pathomorphology of the shoulder in Asian patients with AC compared to healthy volunteers. Methodology/Principal Findings 60 Asian patients with clinically diagnosed AC and 60 healthy volunteers without frozen shoulder underwent MRI of the shoulder joint. All subjects who were age- and sex-matched control ones underwent routine MRI scans of the affected shoulder, including axial, oblique coronal, oblique sagittal T1WI SE and coronal oblique T2WI FSE sequences. Significant abnormal findings were observed on MRI, especially at the rotator cuff interval. The coracohumeral ligament (CHL), articular capsule thickness in the rotator cuff interval as well as the fat space under coracoid process were evaluated. MRI showed that patients with adhesive capsulitis had a significantly thickened coracohumeral ligament and articular capsule in the rotator cuff interval compared to the control subjects (4.2 vs. 2.4 mm, 7.2 vs. 4.4 mm; p<0.05). Partial or complete obliteration of the subcoracoid fat triangle was significantly more frequent in patients with adhesive capsulitis compared with control subjects (73% vs. 13%, 26% vs. 1.6%; p<0.001). Synovitis-like abnormality around the long biceps tendon was significantly more common in patients with adhesive capsulitis than in control subjects. With regards to the inter-observer variability, two MR radiologists had an excellent kappa value of 0.86. Conclusions/Significance MRI can be used to show characteristic findings in diagnosing AC. Thickening of the CHL and the capsule at the rotator cuff interval and complete obliteration of the fat triangle under the coracoid process have been shown to be the most characteristic MR findings seen with AC.

Cystic lesions around the knee are a diverse group of entities, frequently encountered during routine MRI of the knee. These lesions range from benign cysts to complications of underlying diseases such as infection, arthritis, and malignancy. MRI is the technique of choice in characterizing lesions around the knee: to confirm the cystic nature of the lesion, to evaluate the anatomical relationship to the joint and surrounding tissues, and to identify associated intra-articular disorders. We will discuss the etiology, clinical presentation, MRI findings, and differential diagnosis of various cystic lesions around the knee including meniscal and popliteal (Baker's) cysts, intra-articular and extra-articular ganglia, intra-osseous cysts at the insertion of the cruciate ligaments and meniscotibial attachments, proximal tibiofibular joint cysts, degenerative cystic lesions (subchondral cyst), cystic lesions arising from the bursae (pes anserine, prepatellar, superficial and deep infrapatellar, iliotibial, tibial collateral ligament, and suprapatellar), and lesions that may mimic cysts around the knee including normal anatomical recesses. Clinicians must be aware about the MRI features and the differential diagnosis of cystic lesions around the knee to avoid misdiagnosis.