Direct MR arthrography without image guidance: a practical guide, joint-by-joint

Direct MR arthrography (dMRA) is a fundamental technique in diagnosing pathology in major peripheral joints, allowing for precise evaluation of intra-articular structures. Although injection guidance is typically performed using imaging techniques such as ultrasound or fluoroscopy, puncture via anatomical landmarks may be useful in certain circumstances where it has been proven to be a safe and effective procedure. This paper describes the indications and injection technique of dMRA, joint by joint, focusing on the different technical details, from the most common locations, like the shoulder or hip, to those with more restricted clinical indications, such as the wrist, knee, elbow, or ankle. The most relevant anatomical landmarks are detailed for each joint, aiding in the intra-articular introduction of diluted contrast, highlighting the most accessible trajectories and structures to avoid when inserting the needle. Additionally, tips are provided to facilitate proper joint distension. With all this information, this paper aims to serve as a suitable reference guide for performing dMRA without image guidance if needed.

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Magnetic Resonance Imaging of the Shoulder: Interpretation of Common Orthopaedic Injuries

Magnetic resonance imaging (MRI) is frequently obtained to assess for pathology in the setting of shoulder pain and dysfunction. MRI of the shoulder provides diagnostic information that helps optimize patient management and surgical planning. Both general and subspecialized orthopaedic surgeons routinely order and review shoulder MRIs in practice. Therefore, familiarity with the MRI appearance of common shoulder pathologies is important. This document reviews the most common shoulder pathologies using a standardized MRI interpretative approach. Instructional videos demonstrating a musculoskeletal radiologist interpreting normal and abnormal shoulder MRIs are also provided.

ACR Appropriateness Criteria® Chronic Shoulder Pain: 2022 Update

Chronic shoulder pain is an extremely common presenting complaint. Potential pain generators include the rotator cuff tendons, biceps tendon, labrum, glenohumeral articular cartilage, acromioclavicular joint, bones, suprascapular and axillary nerves, and the joint capsule/synovium. Radiographs are typically the initial imaging study obtained in patients with chronic shoulder pain. Further imaging may often be required, with modality chosen based on patient symptoms and physical examination findings, which may lead the clinician to suspect a specific pain generator. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Axillary Anatomy and Pathology: Pearls and "Pitfalls" for Thoracic Imagers

The axilla contains several important structures which exist in a relatively confined anatomic space between the neck, chest wall, and upper extremity. While neoplastic lymphadenopathy may be among the most common axillary conditions, many other processes may be encountered. For example, expanded use of axillary vessels for access routes for endovascular procedures will increase the need for radiologists to access vessel anatomy, patency, and complications that may arise. Knowledge of axillary anatomy and pathology will allow the imager to systematically evaluate the axillae using various imaging modalities.

Humeral Avulsion of the Glenohumeral Ligament: Diagnosis and Management

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The most common type of humeral avulsion of the glenohumeral ligament (HAGL) is a purely ligamentous avulsion involving the anterior inferior glenohumeral ligament (IGHL), but other variants are seen, including posterior lesions and those with an osseous avulsion.

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A central lesion between the intact anterior and posterior bands of the IGHL is gaining recognition as a distinct clinical entity.

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HAGL lesions are most commonly seen in patients with anterior instability without a Bankart tear or in those with persistent symptoms despite having undergone a Bankart repair.

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Magnetic resonance imaging is the most sensitive imaging modality. An arthrogram is helpful with subacute and chronic lesions when the joint is not distended. Arthroscopy is the gold standard for diagnosis.

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While some have reported success with nonoperative management, surgical repair with either arthroscopic or open techniques has provided a high rate of successful outcomes; however, the literature is limited to mostly Level-IV and V evidence.

Anterior Shoulder Instability Part I-Diagnosis, Nonoperative Management, and Bankart Repair-An International Consensus Statement

PURPOSE

The purpose of this study was to establish consensus statements via a modified Delphi process on the diagnosis, nonoperative management, and Bankart repair for anterior shoulder instability.

METHODS

A consensus process on the treatment using a modified Delphi technique was conducted, with 65 shoulder surgeons from 14 countries across 5 continents participating. Experts were assigned to one of 9 working groups defined by specific subtopics of interest within anterior shoulder instability.

RESULTS

The independent factors identified in the 2 statements that reached unanimous agreement in diagnosis and nonoperative management were age, gender, mechanism of injury, number of instability events, whether reduction was required, occupation, sport/position/level played, collision sport, glenoid or humeral bone-loss, and hyperlaxity. Of the 3 total statements reaching unanimous agreement in Bankart repair, additional factors included overhead sport participation, prior shoulder surgery, patient expectations, and ability to comply with postoperative rehabilitation. Additionally, there was unanimous agreement that complications are rare following Bankart repair and that recurrence rates can be diminished by a well-defined rehabilitation protocol, inferior anchor placement (5-8 mm apart), multiple small-anchor fixation points, treatment of concomitant pathologies, careful capsulolabral debridement/reattachment, and appropriate indications/assessment of risk factors.

CONCLUSION

Overall, 77% of statements reached unanimous or strong consensus. The statements that reached unanimous consensus were the aspects of patient history that should be evaluated in those with acute instability, the prognostic factors for nonoperative management, and Bankart repair. Furthermore, there was unanimous consensus on the steps to minimize complications for Bankart repair, and the placement of anchors 5-8 mm apart. Finally, there was no consensus on the optimal position for shoulder immobilization.

LEVEL OF EVIDENCE

Level V, expert opinion.

Glenohumeral Joint Instability: A Review of Anatomy, Clinical Presentation, and Imaging

The glenohumeral joint is intrinsically predisposed to instability because of the bony anatomy but maintained in alignment by many important structures, including the glenoid labrum, glenohumeral ligaments (GHLs), and muscles and tendons. Trauma and overuse can damage these stabilizers, which may then lead to subluxation or dislocation and eventually recurrent instability. This is most common in the anterior direction, which has several recognizable patterns of injury on advanced imaging, including humeral Hill Sachs deformities, bony Bankart lesion of the anteroinferior glenoid, soft tissue Bankart lesions, Bankart variant lesions (Perthes and ALPSA lesions), and HAGL/GAGL lesions. Similar reverse lesions are seen, as well as unique posterior lesions, such as Bennett and Kim's lesions. When symptoms of apprehension and instability in more than one direction are seen, one should consider multidirectional instability, which often presents with a patulous joint capsule. Finally, owing to significant impacts of daily activities and quality of life, surgical correction of labral tears, bony Bankart defects, Hill Sachs defects, and capsular laxity, may be considered.

Contemporary imaging of the pediatric shoulder: pearls and pitfalls

In skeletally immature patients, the presence of growth plates and articular cartilage of the shoulder can create a predisposition for unique injuries not observed in adults. Furthermore, increasing participation in sports by children and adolescents appears to be leading to a corresponding increase in the number of sports-related injuries. The importance of radiologists being familiar with pediatric shoulder imaging and its associated injuries is therefore growing. In this article, we review the normal development and maturation pattern of ossification centers of the shoulder from the early gestational period through adolescence. Brachial plexus birth palsy, physeal injuries, shoulder dislocation, and internal impingement are discussed within the context of the child's age and the mechanism of injury to guide radiologists to a correct diagnosis.

Arthroscopic Bankart Repair With Inferior to Superior Capsular Shift in Lateral Decubitus Position

Traditional Bankart repairs for anterior labral tears of the shoulder use suture anchors to repair the anterior shoulder labrum and capsule to the glenoid. The technique described here involves releasing the anterior capsule of the glenoid and shifting it superiorly along with the labrum before anchoring. The intention of this extra step is to replicate the open technique, where the entire capsule is shifted superiorly on the glenoid.

The broken circle method: a novel technique that enhances detection of Hill-Sachs lesions on internal rotation shoulder radiographs

AIM

To describe and test a new method that increases the conspicuity of a Hill-Sachs lesion on internal rotation (IR) radiographs.

MATERIALS AND METHODS

This study had institutional review board approval. A retrospective search for patients with a prior shoulder dislocation and a Hill-Sachs lesion documented on magnetic resonance imaging (MRI) was performed over a 10-year period identifying 256 test patients. In Part 1, the IR radiographs from test cases were randomised with controls, and three readers scored them independently for the defect. The readers were then taught the Broken Circle (BC) method and re-scored the radiographs. In Part 2, 15 cases of Hill-Sachs lesions that were missed by all readers in Part 1 were randomised with controls, and were shown to 25 radiology residents before (pre-test) and after (post-test) learning the BC method. A paired t-test was used to compare the differences in sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

In Part 1, the sensitivity increased 19.7% (54.1%-73.8%; p<0.05) and NPV increased 10.8% (62.5%-73.3%; p<0.01). In Part 2, post-test sensitivity for residents increased 16.3% (55.2%-71.5%; p<0.0001), accuracy increased 13.4% (64%-77.4%; p<0.0001), and NPV increased 13.3% (40.8%-54.1%; p<0.0001) independent of the level of training. The change in accuracy was also statistically significant for every individual class.

CONCLUSION

The BC method was an effective technique that facilitated detection of a Hill-Sachs lesion at all levels of training, and was useful as a teaching tool.

Anterior Instability: What to Look for

Most first-time anterior glenohumeral dislocations occur as the result of trauma. Many patients suffer recurrent episodes of anterior shoulder instability (ASI). The anatomy and biomechanics of ASI is addressed, as is the pathophysiology of capsulolabral injury. The roles of imaging modalities are described, including computed tomography (CT) and MR imaging with the additional value of arthrography and specialized imaging positions. Advances in 3D CT and MR imaging particularly with respect to the quantification of humeral and glenoid bone loss is discussed. The concepts of engaging and nonengaging lesions as well as on-track and off-track lesions are examined.

Capsular Injury and Inflammation

The capsular and ligamentous structures of the glenohumeral joint are important for stability of the shoulder. These structures are best evaluated by MR imaging. Familiarity with normal and abnormal appearance of the capsular structures of the shoulder is important to ensure that important pathology is not overlooked. Injury to the capsular structures can occur in the setting of trauma and most commonly involves the inferior glenohumeral ligament and axillary pouch. Adhesive capsulitis is a common inflammatory condition with characteristic imaging features that should be considered in the absence of alternative diagnoses.

Psychometric Properties of Performance-Based Functional Tests in Patients With Shoulder Pathologies: A Systematic Review and Meta-analysis

OBJECTIVES

To identify, critically appraise, and synthesize the reported psychometric properties of shoulder performance-based functional tests in patients with shoulder diseases.

DATA SOURCES

MEDLINE, Embase, Scopus, and Cumulative Index to Nursing and Allied Health databases from inception until March 2019 were searched.

STUDY SELECTION

Randomized/prospective studies of patients with shoulder diseases that reported on the psychometric properties (reliability, validity, responsiveness) of performance-based functional tests (Standardized Index of Shoulder Function [FI2S], Functional Impairment Test-Hand and Neck/Shoulder/Arm, Closed Kinetic Chain Upper Extremity Stability Test, Timed Functional Arm and Shoulder Test, Shoulder Function Index [SFInX], and hand to neck, scapula, and opposite scapula).

DATA EXTRACTION

We used the Consensus-Based Standards for the Selection of Health Measurement Instruments 2018 guideline for systematic reviews. We performed a qualitative synthesis in which the results were summarized based on reported measurement properties and study quality.

DATA SYNTHESIS

Eight eligible studies were included with 28 measures (16 reliability; 10 validity; 2 responsiveness). Performance-based functional tests reliability (test-retest, intra- and interrater) measures indicated excellent reliability properties. Intraclass correlation coefficient (ICC) was ≥0.83 and standard error of the mean (SEM) ranged from 0.03-13.3 points. Validity (construct/convergent/concurrent) measures displayed correlations of -0.76 to 0.91 between performance-based functional tests and other patient-reported outcomes (Disabilities of the Arm, Shoulder, and Hand, Constant, Shoulder Pain and Disability Index). Two studies assessed the responsiveness measures performance-based functional tests. Effect sizes of 0.44 and 1.50 and minimal clinically important differences of 10.3 using the anchor-based approach were reported.

CONCLUSIONS

The FI2S and the SFInX are reliable, valid, and responsive in patients with shoulder-related diseases.

Glossary of terms for musculoskeletal radiology

Members of the International Skeletal Society compiled a glossary of terms for musculoskeletal radiology. The authors also represent national radiology or pathology societies in Asia, Australia, Europe, and the USA. We provide brief descriptions of musculoskeletal structures, disease processes, and syndromes and address their imaging features. Given the abundance of musculoskeletal disorders and derangements, we chose to omit most terms relating to neoplasm, spine, intervention, and pediatrics. Consensus agreement was obtained from 19 musculoskeletal radiology societies worldwide.

Understanding the Glenoid Avulsion of the Glenohumeral Ligaments as a Cause of Shoulder Instability: Surgical and Postsurgical Management

In adolescents and young adults, instability is a common shoulder pathology with a myriad of coexisting soft tissue and bony lesions. When evaluating a patient for the cause of instability, care must be given to assess for the infrequent lesions, including glenoid avulsion of the glenohumeral ligaments. This case example illustrates key points in the diagnosis, surgical, and postsurgical management of this less common cause of anterior shoulder instability.

ACR Appropriateness Criteria® Shoulder Pain-Atraumatic

Shoulder pain is one of the most common reasons for musculoskeletal-related physician visits. Imaging plays an important role in identifying the specific cause of atraumatic shoulder pain. This review is divided into two parts. The first part provides a general discussion of various imaging modalities (radiographs, arthrography, nuclear medicine, ultrasound, CT, and MRI) and their usefulness in evaluating atraumatic shoulder pain. The second part focuses on the most appropriate imaging algorithms for specific shoulder conditions including: rotator cuff disorders, labral tear/instability, bursitis, adhesive capsulitis, biceps tendon abnormalities, postoperative rotator cuff tears, and neurogenic pain. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

New concepts of radiologic preoperative evaluation of anterior shoulder instability: on-track and off-track lesions

The shoulder is the most frequently dislocated joint in the body due to a larger range of motion and a small area of articulation between the humeral and glenoid surfaces. Traumatic shoulder dislocations, especially those associated with injury to the labroligamentous or bony stabilizers of the joint, lead to further reduction of articular surface contact with resultant glenohumeral instability and recurrent shoulder dislocations. Imaging plays an increasingly important role in the preoperative evaluation of patients with traumatic shoulder instability by evaluating glenohumeral bone loss (uni- or bipolar), assessing soft tissue injuries and identifying patients at risk of postoperative recurrence. Quantification of bone loss is key to differentiate engaging vs. non-engaging Hill-Sachs lesions, while newer concepts of "on-track" vs. "off-track" lesions are being discussed that can determine the required surgical approaches. In this article, we review the preoperative imaging approaches, traditional treatments, outline the bone loss measurement strategies and review these new tracking concepts with relevant case examples.

Imaging of the Unstable Shoulder

Background:

Unstable shoulder can occur in different clinical scenarios with a broad spectrum of symptoms and presentations: first-time (or recurrent) traumatic acute shoulder anterior dislocation or chronic anterior instability after repeated dislocations.

Imaging in unstable shoulder is fundamental for choosing the right treatment preventing recurrence.

The goal of imaging depends on clinical scenario and patient characteristics.

Method:

Careful selection and evaluation of the imaging procedures is therefore essential to identify, characterize and quantify the lesions. Proper imaging in unstable shoulder cases is critical to the choice of treatment to prevent recurrence, and to plan surgical intervention.

Results:

In acute setting, radiographs have to roughly detect and characterize the bone defects present. At about 7 days, it is recommended to perform a MR to demonstrate lesions to labrum and/or ligaments and bone defects: in acute setting, the MRA is not necessary, because of effusion and hemarthrosis that behave as the contrast medium.

In recurrence, it is fundamental not only to detect lesions but characterize them for planning the treatment. The first study to do is the MRI (with a magnetic field of at least 1.5 Tesla), and if possible MRA, above all in younger patients. Then, on the basis of the pathologic findings as bipolar lesion or severity of bone defects, CT can be performed. PICO method on 2D or 3D CT is helpful if you need to study a glenoid bone loss, with the “en face view” of glenoid, while a 3D CT reconstruction with the humeral head “en face view” is the gold standard to assess an Hill-Sachs lesion.

Conclusion:

The clinical diagnoses of anterior shoulder instability can be different and acknowledgement of imaging findings is essential to guide the treatment choice.

Imaging features are quite different in chronic than in acute scenario. This requires appropriate indications of many different imaging techniques.

Dislocation of the Shoulder Joint - Radiographic Analysis of Osseous Abnormalities

Radiography remains pivotal to the workup of instability lesions of the shoulder, both in the acute as well as the chronic settings. The goal of radiography is to detect osseous abnormalities and locate them in order to determine the direction of instability. In antero-inferior instability, Hill-Sachs lesions are often visible at radiography and should not be confused with various differential diagnoses, which are usually more laterally located. Bankart lesions are more difficult to detect on conventional radiography, but there are less false positives than for Hill-Sachs lesions. The Garth view represents an excellent radiographic view to detect antero-inferior instability impaction fractures at both the humeral and glenoid sides. Accurate quantification of bony abnormalities and detection of lesions to the soft-tissue stabilizers of the shoulder however require advanced cross-sectional imaging techniques.

Advanced Imaging of Glenohumeral Instability: It May Be Less Complicated than It Seems

Glenohumeral joint instability is usually an intimidating topic for most radiologists due to both the complexity of related anatomical and biomechanical considerations and the increasing number of classifications and acronyms reported in the literature in association with this condition. In this short review, we aim to demystify glenohumeral instability by first focusing on the relevant anatomy and pathophysiology. Second, we will review what the important imaging findings are and how to describe them for the clinician in the most relevant yet simple way. The role of the radiologist in assessing glenohumeral instability lesions is to properly describe the stabilizing structures involved (bone, soft-tissue stabilizers, and their periosteal insertion) to localize them and to attempt to characterize them as acute or chronic. Impaction fractures on the glenoid and humeral sides are important to specify, locate, and quantify. In particular, the description of soft-tissue stabilizers should include the status of the periosteal insertion of the capsulo-labro-ligamentous complex. Finally, any associated cartilaginous or rotator cuff tendon lesion should be reported to the clinician.

Glenoid avulsion of the glenohumeral ligament (GAGL): a case report and review of the anatomy

Shoulder dislocations are frequently seen in the general population and can be a cause of instability. Instability can lead to debilitating symptoms and morbidity as a result of progressive damage to the shoulder. Anterior shoulder dislocations are the most frequent type of dislocations and have been studied extensively with MRI. The soft tissue Bankart lesion is the most well-known entity associated with anterior instability; however, additional structural lesions arising from traumatic events have been described in recent literature which also predispose to anterior shoulder instability. One of these lesions, the glenoid avulsion of the glenohumeral ligament (GAGL), involves avulsion of the inferior glenohumeral ligament from the glenoid and involves separation from an intact labrum. In contrast to the Bankart lesion, there has been limited discussion of the GAGL lesion in the literature and very few imaging examples. We report a case of a GAGL diagnosed on MRI and confirmed with arthroscopy. It is discussed in the context of the anatomy of the inferior glenohumeral ligament and the imaging findings.

[Systematics of shoulder instability]

Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to the causative factors as the pathogenesis of instability plays an important role with respect to treatment options. Instabilities are classified into traumatic and atraumatic instabilities as part of a multidirectional instability syndrome and into microtraumatic instabilities.For diagnostics plain radiographs ("trauma series") are performed to document shoulder dislocation and its successful repositioning. Direct magnetic resonance (MR) arthrography is the most important imaging modality for delineation of the different injury patterns of the labral-ligamentous complex and bony structures. Monocontrast computed tomography (CT) arthrography with the use of multidetector CT scanners represents an alternative imaging modality; however, MR imaging should be preferred in the work-up of shoulder instabilities due to the mostly younger age of patients.

Are radiologists superior to orthopaedic surgeons in diagnosing instability-related shoulder lesions on magnetic resonance arthrography? A multicenter reproducibility and accuracy study

BACKGROUND

We compared the diagnostic reproducibility and accuracy of musculoskeletal radiologists with orthopaedic shoulder surgeons in 2 large medical centers in assessing magnetic resonance arthrograms (MRAs) of patients with traumatic anterior shoulder instability.

METHODS

Forty-five surgically confirmed MRAs were assessed by 4 radiologists, 4 orthopaedic surgeons, 2 radiologic teams, and 2 orthopaedic teams. During MRA assessment and surgery, the same 7-lesion scoring form was used. κ Coefficients, sensitivity, specificity, and differences in percentage of agreement or correct diagnosis (P < .05, McNemar test) were calculated per lesion and overall per the 7 lesion types.

RESULTS

The overall κ between the individual radiologists (κ = 0.51, κ = 0.46) and orthopaedic surgeons (κ = 0.46, κ = 0.41) was moderate. Although the overall percentage of agreement between the radiologists was slightly higher than that between the orthopaedic surgeons in both centers (80.0% vs 77.5% and 75.2% vs 73.7%), there was no significant difference. In each medical center, however, the most experienced orthopaedic surgeon was exceedingly more accurate than both radiologists per the 7 lesion types (81.9% vs 72.4%/74.6% and 76.5% vs 67.3%/73.7%). In 3 of 4 cases, this difference was significant. Overall accuracy improvement through consensus assessment was merely established for the weakest member of each team.

CONCLUSION

Experienced orthopaedic surgeons are more accurate than radiologists in assessing traumatic anterior shoulder instability-related lesions on MRA. In case of diagnosis disagreement, these orthopaedic surgeons should base their treatment decision on their own MRA interpretation.

Recurrent anterior glenohumeral instability: the quantification of glenoid bone loss using magnetic resonance imaging

OBJECTIVE

To investigate the accuracy of conventional magnetic resonance imaging (MRI) in determining the severity of glenoid bone loss in patients with anterior shoulder dislocation by comparing the results with arthroscopic measurements.

SUBJECTS AND METHODS

Institutional review board approval and written consent from all patients were obtained. Thirty-six consecutive patients (29 men, seven women; mean age, 34.5 [range, 18-55] years) with recurrent anterior shoulder dislocation (≥3 dislocations; mean, 37.9; range, 3-200) and suspected glenoid bone loss underwent shoulder MRI before arthroscopy (mean interval, 28.5 [range, 9-73] days). Assessments of glenoid bone loss by MRI (using the best-fit circle area method) and arthroscopy were compared. Inter- and intrareader reproducibility of MRI-derived measurements was evaluated using arthroscopy as a comparative standard.

RESULTS

Glenoid bone loss was evident on MRI and during arthroscopy in all patients. Inter- and intrareader correlations of MRI-derived measurements were excellent (intraclass correlation coefficient = 0.80-0.82; r = 0.81-0.86). The first and second observers' measurements showed strong (r = 0.76) and moderate (r = 0.69) interreader correlation, respectively, with arthroscopic measurements.

CONCLUSIONS

Conventional MRI can be used to measure glenoid bone loss, particularly when employed by an experienced musculoskeletal radiologist.