Using abduction and external rotation of the shoulder to increase the sensitivity of MR arthrography in revealing tears of the anterior glenoid labrum

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.

Superior labrum anterior to posterior lesions: Part 1 - Imaging and anatomy with arthroscopic classification

The glenoid labrum deepens the glenoid fossa and allows for the attachment of the long head of the biceps tendon and the glenohumeral ligaments, contributing to the stability of the glenohumeral joint. The superior labrum is a common site of labral injury, especially in athletic activities involving overhead activity. The acronym SLAP (superior labrum anterior to posterior or anteroposterior) lesion was introduced by Snyder and colleagues in 1990 to describe superior labral tears. The article will review the optimal technique to image the glenoid labrum, covering normal labral anatomy with special emphasis on the anatomic variants of the labrum that can be mistaken for SLAP tears by means of colour illustrations, magnetic resonance imaging and correlative arthroscopy images.

Contribution

The illustrated review functions as a crucial radiological guide for both radiologists and orthopaedic surgeons. The combination of illustrations, MR and correlative arthroscopic images enhances the comprehension of normal labral anatomy and its variants. The review underscores the significance of understanding anatomic variations that may be misinterpreted as pathology. This understanding is vital in guiding orthopaedic management for patients, ensuring appropriate treatment strategies.

ABER Position in Direct MR Arthrography of the Shoulder: Useful Adjunct or Waste of Imaging Time?

PURPOSE

The usefulness of direct MR arthrography of the shoulder with additional ABER position (ABER-MRA) has always been discussed. The goals of the following review are to analyze the usefulness of this technique according to the available literature and present recommendations with respect to indications and benefits in diagnostic imaging of shoulder abnormalities in the clinical routine.

METHOD

For this review we assessed the current literature databases of the Cochrane Library, Embase, and PubMed with regard to MRA in the ABER position up to the February 28, 2022. Search terms were "shoulder MRA, ABER", "MRI ABER", "MR ABER", "shoulder, abduction external rotation MRA", "abduction external rotation MRI" and "ABER position". The inclusion criteria were prospective and retrospective studies with surgical and/or arthroscopic correlation within 12 months. Overall, 16 studies with 724 patients fulfilled the inclusion criteria: 10 studies dealing with anterior instabilities, three studies with posterior instabilities and seven studies with suspected rotator cuff pathologies (some studies addressing multiple items).

RESULTS

For anterior instability the use of ABER-MRA in the ABER position led to a significant increase in sensitivity for detecting lesions of the labral ligamentous complex compared with standard 3-plane shoulder MRA (81 % versus 92 %, p = 0.001) while maintaining high specificity (96 %). ABER-MRA demonstrated high sensitivity and specificity (89 % and 100 %, respectively) for SLAP lesions and was able to detect micro-instability in overhead athletes, but case counts are still very small. With regard to rotator cuff tears, no improvement of sensitivity or specificity could be shown with use of ABER-MRA.

CONCLUSION

Based on the currently available literature, ABER-MRA achieves a level of evidence C in the detection of pathologies of the anteroinferior labroligamentous complex. With regard to the evaluation of SLAP lesions and the exact determination of the degree of rotator cuff injury, ABER-MRA can be of additive value, but is still a case-by-case decision.

KEY POINTS

· ABER-MRA is useful in the evaluation of pathologies of the anteroinferior labroligamentous complex. · ABER-MRA does not increase sensitivity or specificity with regard to rotator cuff tears. · ABER-MRA may be helpful for the detection of SLAP lesions and micro-instability in overhead athletes.

CITATION FORMAT

· Altmann S, Jungmann F, Emrich T et al. ABER Position in Direct MR Arthrography of the Shoulder: Useful Adjunct or Waste of Imaging Time?. Fortschr Röntgenstr 2023; 195: 586 - 595.

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.

Advantages of the Use of Axial Traction Magnetic Resonance Imaging (MRI) of the Shoulder in Patients with Suspected Rota-Tor Cuff Tears: An Exploratory Pilot Study

Magnetic Resonance Imaging (MRI) with axial traction is a tool for the assessment of musculoskeletal pathology. Previous reports have demonstrated a better distribution of intra-articular contrast material. No investigations were performed to evaluate glenohumeral joint axial traction MRI in patients with suspected rotator cuff tears. This study aims to assess the morphological changes and the potential advantage of glenohumeral joint axial traction MRI without intra-articular contrast administration in patients with suspected rotator cuff tears. Eleven patients with clinical suspicion of rotator cuff tears underwent a shoulder MRI scan with and without axial traction. PD weighted images with SPAIR fat saturation technique and T1 weighted images with TSE technique were acquired in the oblique coronal, oblique sagittal and axial planes. Axial traction allowed a significant widening of the subacromial space (11.1 ± 1.5 mm vs. 11.3 ± 1.8 mm; p = 0.001) and inferior glenohumeral space (8.6 ± 3.8 mm vs. 8.9 ± 2.8 mm; p = 0.029). With axial traction, there was a significant decrease in measurements of the acromial angle (8.3 ± 10.8° vs. 6.4 ± 9.8°; p < 0.001) and gleno-acromial angle (81 ± 12.8° vs. 80.7 ± 11.5°; p = 0.020). Our investigation demonstrates for the first time significant morphological changes in the shoulder of patients with suspected rotator cuff tears who underwent a glenohumeral joint axial traction MRI.

Diagnostic performance of MRA in abduction and external rotation position in the detection of glenoid labral lesions: a systematic review and meta-analysis

OBJECTIVE

To compare the diagnostic performance of direct magnetic resonance arthrography (MRA) for labral lesions during conventional, abduction and external rotation (ABER), conventional plus abduction, and external rotation (ABER) positioning by using a systematic review and meta-analysis.

MATERIALS AND METHODS

A comprehensive literature search was performed on the two main concepts of magnetic resonance arthrography: extremity position and labral lesions. Inclusion criteria consisted of original studies that assessed the diagnostic accuracy of MR arthrography in ABER and conventional position alone or combined for the diagnosis of labral lesions by using surgical findings as the reference standard. Meta-analyses were performed that compared MR arthrography during conventional positioning, ABER, and conventional plus ABER positioning.

RESULTS

Nine studies met the inclusion and exclusion criteria. A total of 733, 504, and 313 lesions assessed by conventional MRA, ABER MRA, and conventional plus ABER MRA, respectively, were included in our analysis. Pooled sensitivities of MRA in conventional, ABER, and conventional plus ABER position for labral tear diagnosis were 81.5%, 81.6%, and 95.7%, respectively. Pooled specificities of MRA in conventional, ABER, and conventional plus ABER position for labral tear diagnosis were 88.8%, 85.6%, and 94.5%, respectively. Summary receiver operator characteristic (ROC) curve demonstrated improved accuracy of conventional plus ABER MRA compared with conventional MRA or ABER MRA with the area under the curve (AUC) of 0.99, 0.90, and 0.88, respectively.

CONCLUSION

Conventional plus ABER MRA showed increased diagnostic accuracy compared to both ABER MRA and conventional MRA alone in the diagnosis of labral lesions.

Pathology and surgical outcomes of unstable painful shoulders

Background

Boileau et al have reported on the unstable, painful shoulder (UPS), which was defined as painful shoulders without any recognized anteroinferior subluxations or dislocations that were associated with roll-over lesions (ie, instability lesions) on imaging or at arthroscopy. However, they included various pathologies, probably due to the ambiguity in their definitions of UPS. We redefined UPS as follows: (1) shoulder pain during daily or sports activities, (2) traumatic onset, (3) no complaint of shoulder instability, and (4) soft-tissue or bony lesions, such as Bankart or humeral avulsion of glenohumeral ligament lesion, confirmed by arthroscopy. The purpose of this study was to retrospectively investigate pathologies of UPS based on our definitions. We also aimed to assess the outcomes after arthroscopic soft-tissue stabilization for UPS.

Methods

We reviewed patients who were retrospectively diagnosed as UPS based on our definition and underwent arthroscopic stabilization between January 2007 and September 2018. Patients' demographics, physical and radiographic findings, intraoperative findings, clinical outcomes (Rowe scores, Subjective Shoulder Value [SSV], and the visual analog scale [VAS] for pain), and return to play sport (RTPS) were investigated.

Results

This study included 91 shoulders in 91 patients with a mean age of 23 years (range, 15-51). The mean follow-up was 37 months (range, 24-156). Eighty-seven patients were involved in sports activities: collision/contact, 55 patients (60%); overhead, 26 patients (29%). The pain was reproduced during the anterior apprehension test in 86 shoulders (95%). Normal type (49%) predominated in glenoid morphology followed by fragment (bony Bankart) type (37%). Most fragment-type lesions were seen in collision/contact athletes. Intraoperative findings demonstrated that Bankart lesions were found in all patients and Hill-Sachs lesions only in 42%. Magnetic resonance arthrography in the abducted and externally rotated positions showed a Bankart lesion in 76 shoulders (84%). Rowe score, SSV, and pain VAS significantly improved postoperatively (P < .001 for each). Forty-two of 70 athletes (60 %) with > 2-year follow-up returned to the sport at a complete or near-preinjury level. Six (9%) athletes experienced reinjury.

Conclusion

All shoulders that were diagnosed as UPS with our definition had a Bankart lesion. There seemed to be two different types of pathologies: Bankart lesions in lax shoulders and bony Bankart lesions in collision/contact athletes. The pain experienced during the anterior apprehension test may be useful for the diagnosis of UPS. Arthroscopic soft-tissue stabilization yielded good clinical outcomes with a high RTPS rate, but the reinjury rate was relatively high.

The Top 50 Most-Cited Papers in the Diagnosis and Management of SLAP Tears

Purpose

To identify and characterize the top 50 most-cited articles regarding SLAP tears.

Methods

Referencing the methodology of previous citation analyses, varying Boolean searches were performed using the Web of Science database and the search terms yielding the greatest number of results was used. The top 50 most-cited articles were identified and the following data points were gathered from each article: author, institution, country of origin, year of publication, publishing journal, level of evidence, and citation density.

Results

The total number of citations was 7834, with a median of 106 citations. The top 50 list was largely composed of diagnostic level I, II, and III studies (5, 7, and 8 total publications, respectively) and therapeutic level III (6 publications) or level IV (10 publications). Most articles originated from the United States (40). In total, 19 of the top 50 most-cited articles were published in the American Journal of Sports Medicine, followed by Arthroscopy (15) and the Journal of Bone and Joint Surgery (5).

Conclusions

Our analysis demonstrated a correlation with earlier publications being cited more frequently than recent studies. Importantly, the current study found that therapeutic studies in the most cited list were largely level III or level IV evidence. This makes the management of SLAP tears seem anecdotal, with little in the way of high-impact level I or level II therapeutic studies. We must reconsider our current understanding of SLAP tears and their management with more studies that demonstrate a clearer treatment algorithm for these common injuries of the shoulder.

Clinical Relevance

Given the complexity of SLAP tears, this list of the most-cited articles can provide a reference point to better guide practice, resident education, and future areas of orthopaedic research.

Optimization of MRI Protocol for the Musculoskeletal System

자기공명영상(magnetic resonance imaging; 이하 MRI)은 다른 영상 기법에 비해 연부 조직 대조도와 해상력이 높아 근골격계 영역에서 중요한 진단 기기로 이용되고 있다. 최근 MRI 관련 기술이 발달함에 따라 빠른 영상 촬영 및 다양한 영상면 재구성이 가능해짐으로써 입체적인 근골격계 해부학적 구조와 병변을 더욱 잘 평가할 수 있게 되었다. 또한, MRI는 최적화 정도에 따라 영상의 질, 진단 정확도 및 촬영 시간 등이 달라지며, MRI 장치의 효율적 인 운용과도 관련이 있어, 이를 관리하는 것은 영상의학과 의사의 중요한 역할이다. 본 종설에서는 6개 주요 관절에 따른 환자 자세, radiofrequency 코일 선택, 권장 펄스열, 영상면 구성 및 스캔 파라미터에 대한 지침을 제시함으로써 근골격계 MRI의 최적화에 도움이 되고자 한다.

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.

Biomechanics of posterior shoulder instability - current knowledge and literature review

Posterior instability of the shoulder is a rare condition and represents about 10% of shoulder instability. It has become more frequently recognized in the last year, even though it is more difficult to diagnose than anterior shoulder instability. As this form of shoulder pathology is somewhat rare, biomechanical knowledge is limited. The purpose of our study was to perform an extensive literature search, including PubMed and Medline, and to give an overview of the current knowledge on the biomechanics of posterior shoulder instability. The PubMed/Medline databases were utilized, and all articles related to posterior shoulder instability and biomechanics were included to form a comprehensive compilation of current knowledge. A total of 93 articles were deemed relevant according to our inclusion and exclusion criteria. As expected with any newly acknowledged pathology, biomechanical studies on posterior shoulder instability remain limited in the literature. Current biomechanical models are performed in a static manner, which limits their translation for explaining a dynamic pathology. Newer models should incorporate dynamic stabilization of both the rotator cuff and scapulothoracic joint. There is a current lack of knowledge with regards to the pathomechanism of posterior shoulder instability, with no consensus on appropriate treatment regimens. Further investigation is therefore required at both basic science and clinical levels.

Traumatic Instability: Treatment Options and Considerations for Recurrent Posttraumatic Instability

Recurrent traumatic glenohumeral instability is a complex problem with multiple variables to consider, but patient demographics, activities, as well as clinical and radiographic findings provide significant information to help choose the best treatment option. Although nonoperative treatment is a viable option for primary glenohumeral instability and in-season instability, recurrent instability exhibits anatomic factors which render nonsurgical treatment limited in scope. A proper patient history, clinical examination, and standard and advanced imaging are necessary in the assessment of patients with recurrent traumatic instability. Age, activity, hypermobility, tissue quality, glenoid and humeral head bone stock, and any prior surgical treatment are factors that must be considered for surgical planning. Open and arthroscopic Bankart repairs are good surgical options when bone loss is not an issue but increasing glenoid or humeral osseous deficiency in this setting frequently warrants additional procedures which address bony insufficiency. Controversy remains concerning the threshold value for glenoid bony deficiency and combined, bipolar defects, but this critical number may be less than previously suspected. Despite this controversy, successful surgical treatment of recurrent glenohumeral instability is possible when properly assessed and the correct surgery applied.

Diagnosis of glenoid labral tears using 3-tesla MRI vs. 3-tesla MRA: a systematic review and meta-analysis

BACKGROUND

Various protocols exist for magnetic resonance arthrogram (MRA) of the shoulder, including 3D isotropic scanning and positioning in neutral (2D neutral MRA), or abduction-external-rotation (ABER).

HYPOTHESIS

MRA does not improve diagnostic accuracy for labral tears when compared to magnetic resonance imaging (MRI) performed using 3-Tesla (3T) magnets.

METHOD

Systematic review of the Cochrane, MEDLINE, and PubMed databases according to PRISMA guidelines. Included studies compared 3T MRI or 3T MRA (index tests) to arthroscopic findings (reference test). Methodological appraisal performed using QUADAS-2. Pooled sensitivity and specificity were calculated.

RESULTS

Ten studies including 929 patients were included. Index test bias and applicability were a concern in the majority of studies. The use of arthroscopy as the reference test raised concern of verification bias in all studies. For anterior labral lesions, 3T MRI was less sensitive (0.83 vs. 0.87 p = 0.083) than 3T 2D neutral MRA. Compared to 3T 2D neutral MRA, both 3T 3D Isotropic MRA and 3T ABER MRA significantly improved sensitivity (0.87 vs. 0.95 vs. 0.94). For SLAP lesions, 3T 2D neutral MRA was of similar sensitivity to 3T MRI (0.84 vs. 0.83, p = 0.575), but less specific (0.99 vs. 0.92 p < 0.0001). For posterior labral lesions, 3T 2D neutral MRA had greater sensitivity than 3T 3D Isotropic MRA and 3T MRI (0.90 vs. 0.83 vs. 0.83).

CONCLUSIONS

At 3-T, MRA improved sensitivity for diagnosis of anterior and posterior labral lesions, but reduced specificity in diagnosis of SLAP tears. 3T MRA with ABER positioning further improved sensitivity in diagnosis of anterior labral tears.

LEVEL OF EVIDENCE

IV.

Axial traction magnetic resonance imaging (MRI) of the glenohumeral joint in healthy volunteers: initial experience

OBJECTIVE

Evaluate technical feasibility and potential applications of glenohumeral (GH) joint axial traction magnetic resonance imaging (MRI) in healthy volunteers.

MATERIALS AND METHODS

Eleven shoulders were imaged in neutral and with 4kg axial traction at 3T. Quantitative measurements were assessed.

RESULTS

Axial traction was well tolerated. There was statistically significant widening of the superior GH joint space (p=0.002) and acromial angle (p=0.017) with traction. Inter-rater agreement was high.

CONCLUSION

GH joint axial traction MRI is technically feasible and well tolerated in volunteers. Traction of the capsule, widening of the superior GH joint space and acromial angle were observed.

What can the Radiologist do to Help the Surgeon Manage Shoulder Instability?

Imaging of the shoulder forms an important adjunct in clinical decision making in patients with shoulder instability. The typical lesions related with classic anterior and anteroinferior shoulder dislocation are an anteroinferior labral avulsion with or without bony fragment of bone loss – a (bony) Bankart lesion – and a posterolateral humeral head impaction fracture – the Hill-Sachs lesions. These are relatively straightforward to identify on imaging, although normal variants of the inferior labrum and variants of labral damage may cause confusion. Other capsuloligamentous lesions, often associated with less typical types of instability, are much more difficult to identify correctly on imaging, as they occur in the anterosuperior part of the glenohumeral joint with its many normal variants or because they result in more subtle, and therefore easily overlooked, changes in morphology or signal intensity. This paper aims at describing the appearance of the normal and pathologic glenohumeral joint related to shoulder instability. Ample reference will be given as to why identification of abnormalities, whether normal or pathologic, is important to the surgeon facing a treatment decision.

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.

Usefulness of Unenhanced MRI and MR Arthrography of the Shoulder in Detection of Unstable Labral Tears

OBJECTIVE

Shoulder surgeons commonly intervene to repair unstable labral tears (tears that displace with patient movement). Surgeons can detect unstable tears at surgery. It is difficult to be certain if a tear is unstable from a static MR image. This study reports the comparative benefits of using unenhanced MRI and MR arthrography together to detect unstable labral tears.

MATERIALS AND METHODS

One hundred fifty consecutive unenhanced shoulder MRI and MR arthrography examinations performed on the same patients were reviewed retrospectively by consensus reading of two musculoskeletal radiologists. Both unenhanced MRI and MR arthrography were performed on each patient on the same day. Labral tears were assessed. It was also determined if there was any difference in position of the labral tear between unenhanced MR images and MR arthrograms. A change in position of 4 mm or more between unenhanced MR images and MR arthrograms was considered indicative of an unstable tear. All patients proceeded to arthroscopy.

RESULTS

Of these 150 patients, 94 had superior labral anterior-to-posterior (SLAP) tears, 53 had posterior labral tears, and 42 had anterior labral tears on MRI. All lesions described on MRI were described on arthroscopy. Twenty-three SLAP tears, 16 posterior labral tears, and 17 anterior labral tears showed a change in the position of the labral tear when comparing unenhanced MR images versus MR arthrograms of 4 mm or more. All of these labral tears were considered unstable by the surgeon, and all of these patients had surgical tacking performed. The other labral tears showed motion on unenhanced MR images and MR arthrograms of less than 4 mm. All of these tears except for three were considered stable on arthroscopic examination. There were five SLAP tears, three anterior labral tears, and four posterior labral tears seen on arthroscopy that were not seen on unenhanced MRI or MR arthrography. The tears not seen on unenhanced MRI or MR arthrography were considered stable at arthroscopy.

CONCLUSION

In this study, unenhanced MRI and MR arthrography of the shoulder was useful in diagnosing unstable labral tears in 23 patients with SLAP tears, 16 patients with posterior labral tears, and 17 patients with anterior labral tears. This information was useful in surgical planning. Of 133 tears that moved less than 4 mm on unenhanced MR images and MR arthrograms, 130 were considered stable on arthroscopy.

Anteroposterior translation of the glenohumeral joint in various pathologies: differences between shoulder MRI in the adducted neutral rotation and abducted externally rotated positions

PURPOSE

The present study was performed to determine the translation of the glenohumeral joint in patients with and without shoulder lesions by comparing the magnetic resonance images obtained in the conventional adducted neutral rotation position with those obtained in the abducted externally rotated position.

METHODS

Two hundred and eighty-five consecutive shoulders without rotator cuff tears that had been subjected to magnetic resonance imaging (MRI) without arthrography in the abducted externally rotated position were reviewed retrospectively. Among them, 50 shoulders without pathology were selected at random to be compared with three shoulder pathology groups, comprising shoulders with superior labrum, anterior-to-posterior (SLAP) lesions without range of motion (ROM) limitation (group I, 47 shoulders), with massive rotator cuff tears without ROM limitation (group II, 20 shoulders), and with full-thickness subscapularis tendon tears without ROM limitation (group III, 20 shoulders). Glenohumeral translation in the anterior-to-posterior direction relative to the glenoid face was evaluated using a method based on the glenohumeral contact point (CP) and humeral head centre (HHC) in the adducted neutral rotation and abducted externally rotated views, which were measured by three orthopaedic surgeons. For each shoulder, the differences in translation for the glenohumeral CP and HHC between the adducted neutral rotation and abducted externally rotated views were calculated as relative posterior translation in millimetres.

RESULTS

The differences in ΔCP and ΔHHC between group I and the normal control group were not statistically significant. The differences in ΔCP (P = 0.001) and ΔHHC (P = 0.001) between group II and the normal control group were statistically significant. Additionally, the differences in ΔCP and ΔHHC between group III and the normal control group were not statistically significant.

CONCLUSIONS

The MRI in abducted externally rotated view in patients with SLAP lesions or full-thickness subscapularis tendon tears diagnosed by conventional MRI alone showed no significant glenohumeral posterior translation relative to the adducted neutral rotation view in the present study. However, the abducted externally rotated view in patients with massive rotator cuff tears showed significant glenohumeral anterior translation relative to the adducted neutral rotation view.

Approach to the treatment of primary anterior shoulder dislocation: A review

Glenohumeral joint dislocation is common among younger, active patients. Anterior dislocation is the most common direction of instability following a traumatic event. Due to a high rate of recurrence following primary traumatic anterior shoulder dislocation, an evidence-based approach is necessary to determine the best treatment regime for a patient presenting with this problem. A history, physical examination, and radiographic imaging can help guide treatment recommendations by determining the extent of soft tissue damage following dislocation. Controversies in the treatment of the first-time dislocator include the length and position of immobilization following dislocation, and the role of initial surgical stabilization. This article outlines the treatment options for the first-time glenohumeral dislocator, with an emphasis on the available evidence in the literature. Where applicable, the criteria known as the Strength of Recommendation Taxonomy were used to summarize the strength of evidence available for recommendations.

MR arthrography including abduction and external rotation images in the assessment of atraumatic multidirectional instability of the shoulder

OBJECTIVE

To evaluate diagnostic signs and measurements in the assessment of capsular redundancy in atraumatic multidirectional instability (MDI) of the shoulder on MR arthrography (MR-A) including abduction/external rotation (ABER) images.

METHODS

Twenty-one MR-A including ABER position of 20 patients with clinically diagnosed MDI and 17 patients without instability were assessed by three radiologists. On ABER images, presence of a layer of contrast between the humeral head (HH) and the anteroinferior glenohumeral ligament (AIGHL) (crescent sign) and a triangular-shaped space between the HH, AIGHL and glenoid (triangle sign) were evaluated; centring of the HH was measured. Anterosuperior herniation of the rotator interval (RI) capsule and glenoid version were determined on standard imaging planes.

RESULTS

The crescent sign had a sensitivity of 57 %/62 %/48 % (observers 1/2/3) and specificity of 100 %/100 %/94 % in the diagnosis of MDI. The triangle sign had a sensitivity of 48 %/57 %/48 % and specificity of 94 %/94 %/100 %. The combination of both signs had a sensitivity of 86 %/90 %/81 % and specificity of 94 %/94 %/94 %. A positive triangle sign was significantly associated with decentring of the HH. Measurements of RI herniation, RI width and glenoid were not significantly different between both groups.

CONCLUSIONS

Combined assessment of redundancy signs on ABER position MR-A allows for accurate differentiation between patients with atraumatic MDI and patients with clinically stable shoulders; measurements on standard imaging planes appear inappropriate.

KEY POINTS

MR arthrography has the possibility to accurately identify patients with atraumatic MDI. Imaging of the shoulder in abduction and external rotation provides additive information. Capsular enlargement of the shoulder can be diagnosed on MR arthrography.

An overview of shoulder instability and its management

The assessment and management of patients with instability of the shoulder joint can be challenging, due to the varying ways patients present, the array of different classification systems, the confusing terminology used and the differing potential management strategies. This review article aims to provide a clear explanation of the common concepts in shoulder instability and how they relate to the assessment and management of patients.

There are sections covering the mechanisms of shoulder stability, the clinical assessment of patients and imaging techniques. Beyond that there is a discussion on the common classifications systems used and the typical management options.

Some patients fall into reasonably well defined categories of classification and in these cases, the management plan is relatively easy to define. Unfortunately, other patients can elude simple classification and in these instances their management requires very careful consideration. Further research may help to facilitate a better understanding of management of the patients in this latter group.

Sublabral clefts and recesses in the anterior, inferior, and posterior glenoid labrum at MR arthrography

PURPOSE

To determine the prevalence of a normal variant cleft/recess at the labral-chondral junction in the anterior, inferior, and posterior portions of the shoulder joint.

MATERIALS AND METHODS

One hundred and three consecutive patients (106 shoulders) who had a direct MR arthrogram followed by arthroscopic surgery were enrolled in this IRB-approved study. Scans were carried out on a 1.5-T scanner with an eight-channel shoulder coil. The glenoid rim was divided into eight segments and the labrum in all but the superior and anterosuperior segments was evaluated by two radiologists for the presence of contrast between the labrum and articular cartilage. We measured the depth of any cleft/recess and correlated the MR findings with surgical results. Generalized estimating equation models were used to correlate patient age and gender with the presence and depth of a cleft/recess, and Cohen's kappa values were calculated for interobserver variability.

RESULTS

For segments that were normal at surgery, a cleft/recess was present within a segment on MR arthrogram images in as few as 7 % of patients (within the posteroinferior segment by observer 1), and in up to 61 % of patients (within the posterosuperior segment by observer 1). 55-83 % of these were only 1 mm deep. A 2- to 3-mm recess was seen within 0-37 % of the labral segments, most commonly in the anterior, anteroinferior, and posterosuperior segments. Age and gender did not correlate with the presence of a cleft/recess, although there was an association between males and a 2- to 3-mm deep recess (p = 0.03). The interobserver variability for each segment ranged between 0.15 and 0.49, indicating slight to moderate agreement.

CONCLUSION

One-mm labral-chondral clefts are not uncommon throughout the labrum. A 2- to 3-mm deep smooth, medially curved recess in the anterior, anteroinferior or posterosuperior labrum can rarely be seen, typically as a continuation of a superior recess or anterosuperior labral variant.

Accuracy of abduction-external rotation MRA versus standard MRA in the diagnosis of intra-articular shoulder pathology

The goal of this study was to compare the accuracy of abduction-external rotation magnetic resonance arthrography (ABERMRA) with standard MRA in the diagnosis of intra-articular shoulder pathology.One hundred three consecutive patients undergoing preoperative direct MRA and subsequent arthroscopic examination were included in the study. Seventy-eight patients underwent standard MRA and 25 underwent ABERMRA. Specialist-trained musculoskeletal radiologists reported all scans, and attending shoulder surgeons performed all arthroscopies. Arthroscopic assessment revealed 11 partial-thickness rotator cuff tears, 3 full-thickness tears, 64 labral lesions (48 soft tissue and 16 significant bony), and 17 superior labrum anterior-posterior (SLAP) tears. The sensitivity/specificity for standard MRA was 0.56/0.99 for partial-thickness rotator cuff tears, 1.00/1.00 for full-thickness rotator cuff tears, 0.75/0.91 for soft tissue labral tears, 0.58/1.00 for significant bony glenoid lesions, and 0.50/0.91 for SLAP tears. Abduction-external rotation magnetic resonance arthrography increased the sensitivity/specificity to 1.00/0.85 for soft tissue labral tears, 0.75/1.00 for significant bony glenoid lesions, and 1.00/1.00 for SLAP tears, although it missed 2 of 2 partial-thickness rotator cuff tears.This study suggests that standard MRA is a valuable investigation tool for instability, SLAP tears, and rotator cuff tears, although limitations exist. Additional ABERMRA sequences appear to improve the diagnostic accuracy of soft tissue anterior and posterior labral tears, SLAP tears, and significant bony glenoid lesions and should be routinely requested by shoulder surgeons when ordering MRAs to obtain the maximum benefit from this invasive investigation.

Sensitivity of preoperative magnetic resonance imaging and magnetic resonance arthrography in detection of panlabral tears of the glenohumeral joint

PURPOSE

The purpose of this study was to evaluate the sensitivity of preoperative magnetic resonance imaging (MRI) in detecting combined lesions of the glenoid labrum involving tears of the anterior, posterior, and superior labrum.

METHODS

Preoperative MRI findings were available in 46 cases of arthroscopic repair of combined tears of the anterior, posterior, and superior labrum (mean age, 31 years), including 23 noncontrast MRI studies and 24 magnetic resonance (MR) arthrography studies (1 patient had both). MRI findings were compared with the status of the labrum at the time of arthroscopy, and the sensitivity of MRI was determined.

RESULTS

MRI showed evidence of combined lesions of the anterior, posterior, and superior labrum in only 10 of 47 studies (21.3%). Only 2 of 23 (8.7%) tears were detected by noncontrast MRI, compared with 8 of 24 (33.3%) by MR arthrography (P = .07). Non-contrast MRI showed evidence of labral pathology in more than one direction in 10 of 23 studies (43.5%), compared with 20 of 24 MR arthrography studies (83.3%) (P = .006). Noncontrast MRI showed no evidence of a labral tear in 3 of 23 patients (13.0%), whereas no MR arthrogram was completely negative for a labral tear (0%) (P = .11).

CONCLUSIONS

Combined tears of the anterior, posterior, and superior glenoid labrum are infrequent injuries that are typically not completely defined by either noncontrast MRI or MR arthrography.

LEVEL OF EVIDENCE

Level III, diagnostic study.

The added value of ABER position for the detection and classification of anteroinferior labroligamentous lesions in MR arthrography of the shoulder

PURPOSE

The purpose of this study is to compare MR arthrography in abduction and external rotation (ABER) position with conventional MR arthrography in neutral position for the detection and further classification of anteroinferior labroligamentous lesions.

MATERIALS AND METHODS

Two hundred and twenty-nine cases of shoulder MR arthrography with subsequent arthroscopy were retrospectively evaluated. All MR arthrograms in ABER position and neutral position were independently assessed by two radiologists who were blinded to the arthroscopic findings. Sensitivities and specificities of both positions for detection and further categorization of anteroinferior labroligamentous lesions were calculated and compared using paired McNemar test. K values were calculated to quantify the level of interobserver agreement.

RESULTS

At arthroscopy, 24 Bankart lesions, 59 ALPSA lesions, 39 Perthes lesions, 8 GLAD lesions, 4 ALIPSA lesions, 31 nonclassifiable lesions and 60 intact anteroinferior complexes were found. The sensitivity of MR arthrography in ABER position for detecting anteroinferior labroligamentous lesions was significantly higher than that of in neutral position (92.7-94.5% versus 81.8-83%, P<0.05). For the detection rate of the mentioned 6 subtypes of lesions, only the Perthes lesions had significant improvement in ABER position when compared with conventional MR arthrography (observer 1, 61.5-87.2%, P=0.006; observer 2, 69.2-92.3%, P=0.004). MR arthrography in ABER position was more effective in identifying of Perthes lesions (66.7-74.4% versus 35.9-40%, P<0.05) while the conventional MR arthrography was more effective in accurate diagnose of ALPSA lesions (74.6-78.0% versus 54.2-55.9%, P<0.05). No statistically significant difference of the diagnostic accuracy was found between the two positions for Bankart lesions, GLAD lesions, and ALIPSA lesions.

CONCLUSION

MR arthrography in ABER position has more added value on detection of Perthes lesions in evaluation of anteroinferior labroligamentous complex tear.

Throwing injuries of the upper extremity

The overhead throwing motion is a complex sequence of maneuvers that requires coordinated muscle activity in the upper and lower extremities. The shoulder and elbow are subject to multidirectional forces and are particularly vulnerable to injury during specific phases of the overhead throwing motion. Ligamentous, tendinous, neural, and osseous pathology that may occur in the shoulder or elbow of an overhead-throwing athlete will be discussed, with an emphasis on the role of MR imaging and MR arthrography.

Imaging evaluation of the rotator cuff

The rotator cuff is a complex network of interwoven tendons that plays a key role in glenohumeral movement and stability. Cuff abnormality is a common source of shoulder pain, but the clinical presentation is often nonspecific and, as a result, diagnostic imaging, especially magnetic resonance imaging, plays a key role in evaluating these patients. This article reviews imaging modalities available for evaluating the cuff, normal cuff anatomy, and common pathologic conditions that affect it.

Direct MR arthrography of the shoulder under axial traction: feasibility study to evaluate the superior labrum-biceps tendon complex and articular cartilage

PURPOSE

To assess the value of adding axial traction to direct MR arthrography of the shoulder, in terms of subacromial and glenohumeral joint space widths, and coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material.

MATERIALS AND METHODS

Twenty-one patients investigated by direct MR arthrography of the shoulder were prospectively included. Studies were performed with a 3 Tesla (T) unit and included a three-dimensional isotropic fat-suppressed T1-weighted gradient-recalled echo sequence, without and with axial traction (4 kg). Two radiologists independently measured the width of the subacromial, superior, and inferior glenohumeral joint spaces. They subsequently rated the amount of contrast material around the superior labrum-biceps tendon complex and between glenohumeral cartilage surfaces, using a three-point scale: 0 = no, 1 = partial, 2 = full.

RESULTS

Under traction, the subacromial (Δ = 2.0 mm, P = 0.0003), superior (Δ = 0.7 mm, P = 0.0001) and inferior (Δ = 1.4 mm, P = 0.0006) glenohumeral joint space widths were all significantly increased, and both readers noted significantly more contrast material around the superior labrum-biceps tendon complex (P = 0.014), and between the superior (P = 0.001) and inferior (P = 0.025) glenohumeral cartilage surfaces.

CONCLUSION

Direct MR arthrography of the shoulder under axial traction increases subacromial and glenohumeral joint space widths, and prompts better coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material.

A meta-analysis of the diagnostic test accuracy of MRA and MRI for the detection of glenoid labral injury

PURPOSE

Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) have gained increasing favour in the assessment of patients with suspected glenoid labral injuries. The purpose of this study was to determine the diagnostic accuracy of MRI or MRA in the detection of gleniod labral lesions.

MATERIALS AND METHODS

A systematic review was undertaken of the electronic databases Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, AMED and CINAHL, in addition to a search of unpublished literature databases. All studies which compared the ability of MRI or MRA (index test) to assess gleniod labral tears or lesions, when verified with a surgical procedure (arthroscopy or open surgery-reference test) were included. Data extraction and methodological appraisal using the QUADAS tool were both conducted by two reviewers independently. Data were analysed through a summary receiver operator characteristic curve and pooled sensitivity and specificity analysis were calculated with 95% confidence intervals.

RESULTS

Sixty studies including 4,667 shoulders from 4,574 patients were reviewed. There appeared slightly greater diagnostic test accuracy for MRA over MRI for the detection of overall gleniod labral lesions (MRA-sensitivity 88%, specificity 93% vs. MRI sensitivity 76% vs. specificity 87%). Methodologically, studies recruited and identified their samples appropriately and clearly defined the radiological procedures. In general, it was not clearly defined why patients were lost during the study, and studies were poor at recording whether the same clinical data were available to the radiologist interpreting the MRI or MRA as would be available in clinical practice. Most studies did not state whether the surgeon interpreting the arthroscopic procedure was blinded to the results of the MR or MRA imaging.

CONCLUSIONS

Based on the available literature, overall MRA appeared marginally superior to MRI for the detection of glenohumeral labral lesions.

LEVEL OF EVIDENCE

Level 2a.

Anterior shoulder instability: correlation between magnetic resonance arthrography, ultrasound arthrography and intraoperative findings

The purpose of the present study was to determine ultrasound (US) arthrography diagnostic accuracy in patients with recurrent shoulder dislocation by comparing US arthrography and magnetic resonance arthrography (MRA) with intraoperative findings. Fifty-six consecutive patients with diagnosis of chronic anterior instability of the shoulder were evaluated for assessment of bone and soft tissue lesions by three radiologists. Twenty-five cases were confirmed by surgery. Sensitivity, specificity, inter- and intraobserver agreement were calculated. Ultrasound sensitivity ranged from 20% to 100% and specificity from 25% to 90%. MRA sensitivity ranged from 80% to 100% and specificity from 50% to 100%. Interobserver agreement was good for MRA (0.54-0.70) and fair for US arthrography (0.19-0.40). Despite a higher interobserver variability for US arthrography than for MRA, our results indicate that US is capable of demonstrating bone and soft tissue lesions related to chronic instability of the shoulder in the presence of intra-articular fluid.

Magnetic resonance imaging in glenohumeral instability

The glenohumeral joint enables tremendous range of motion at the expense of stability. Functional stability is maintained by the synchronous coordination of complex static and dynamic structures. Symptomatic glenohumeral instability most often results from injury to the inferior labral-ligamentous complex, the primary passive stabilizer of the shoulder. This article reviews the structures important in glenohumeral stabilization and illustrates their normal appearances and the abnormalities associated with anterior, posterior, and multidirectional instability. These lesions are discussed in the context of therapeutic decision making.

Technical update on magnetic resonance imaging of the shoulder

Improvement in both hardware and software has opened up new opportunities in magnetic resonance (MR) imaging of the shoulder. MR imaging at 3-T has become a reality, with the prospect of 7-T imaging on the horizon. The art of MR arthrography continues to improve, aided by the use of novel imaging positions. New techniques for three-dimensional imaging, the reduction of metal artifact, and biochemical imaging of cartilage hold great promise.

Interdisciplinary inter-observer agreement and accuracy of MR imaging of the shoulder with arthroscopic correlation

INTRODUCTION

Differences between radiologists and orthopaedic surgeons in the interpretation of MR images of the shoulder joint are experienced in daily clinical practice. This study set out to evaluate the inter-observer agreement between radiologists and orthopaedic surgeons in assessing pathology on MR imaging of the shoulder joint. Also, we determined the accuracy of the observers with arthroscopy as the standard of reference.

MATERIALS AND METHODS

Two radiologists and one orthopaedic surgeon reviewed 50 MR studies-25 conventional MR examinations and 25 MR arthrographies-of patients with shoulder complaints who had undergone MR imaging and subsequently arthroscopic surgery. The assessment was independent and blinded. All observers evaluated the MR examinations twice. Standard evaluation forms were used to score for pathology of rotator cuff, glenoid labrum, tendon of the long head of the biceps brachii and glenohumeral ligaments. The presence or absence of osteoarthritis, SLAP lesions, Bankart lesions, Hill-Sachs lesions or impingement was also noted. Intra- and inter-observer agreement, the sensitivity and specificity were calculated. Differences in percentages of correctly diagnosed lesions were tested for significance using McNemar's test.

RESULTS

There was a poor inter-observer agreement between the orthopaedic surgeon and the radiologists in assessing Bankart lesions and ligamentous lesions. We found significant differences between the radiologists and the orthopaedic surgeon in the assessment of osteoarthritis, Hill-Sachs lesions and impingement.

CONCLUSION

The orthopaedic surgeon and radiologists differed in their interpretation of what defines a Bankart lesion and what defines a ligamentous lesion. The orthopaedic surgeon was significantly more accurate in assessing impingement.

Current imaging of the rotator cuff

Rotator cuff pathology is a common cause of shoulder pain, and imaging plays a major role in the management of shoulder problems. General radiography may be useful as an initial screening test particularly in trauma and arthritis. Musculoskeletal ultrasound and magnetic resonance imaging are the most suitable modalities for the investigation of the rotator cuff, having high sensitivities and specificities for full-thickness tears. Musculoskeletal ultrasound and magnetic resonance imaging are less accurate in the detection of partial-thickness tears with greater observer variability. This article reviews the normal and pathologic imaging features of the rotator cuff and highlights the potential usefulness and limitations of various imaging modalities in the assessment of the tendon and the potential impact of imaging findings on clinical patient care.

Spectrum of magnetic resonance imaging findings in clinical glenohumeral instability

The glenohumeral joint is the most commonly dislocated joint in the body, and anterior instability is the most common type of shoulder instability. Depending on the etiology and the age of the patient, there may be associated injuries, for example, to the anterior-inferior labro-ligamentous structures (in young individuals with traumatic instability) or to the bony components (commoner in the elderly), which are best visualized using MRI and MR arthrography. Anterior instability is associated with a Bankart lesion and its variants and abnormalities of the anterior band of the inferior glenohumeral ligament (IGHL), whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesions. Cases of multidirectional instability often have no labral pathology on imaging but show specific osseous changes including increased chondrolabral retroversion. This article reviews the relevant anatomy in brief and describes the MRI findings in each type, with the imaging features of the common abnormalities.

Magnetic resonance imaging in glenohumeral instability

The glenohumeral joint is the most commonly dislocated joint of the body and anterior instability is the most common type of shoulder instability. Magnetic resonance (MR) imaging, and more recently, MR arthrography, have become the essential investigation modalities of glenohumeral instability, especially for pre-procedure evaluation before arthroscopic surgery. Injuries associated with glenohumeral instability are variable, and can involve the bones, the labor-ligamentous components, or the rotator cuff. Anterior instability is associated with injuries of the anterior labrum and the anterior band of the inferior glenohumeral ligament, in the form of Bankart lesion and its variants; whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesion. Multidirectional instability often has no labral pathology on imaging but shows specific osseous changes such as increased chondrolabral retroversion. This article reviews the relevant anatomy in brief, the MR imaging technique and the arthrographic technique, and describes the MR findings in each type of instability as well as common imaging pitfalls.

Displaceability of SLAP lesion on shoulder MR arthrography with external rotation position

OBJECTIVE

To investigate the usefulness of the external rotation (ER) position on magnetic resonance (MR) arthrography for the diagnosis of superior labral anterior to posterior (SLAP) lesion.

MATERIALS AND METHODS

Approval of institutional review board was obtained, and informed consent was waived. The MR arthrograms of 210 shoulders that were arthroscopically confirmed as SLAP lesion in 163 shoulders and intact superior labrum in 47 shoulders were retrospectively reviewed in each neutral and ER position for the diagnosis of SLAP lesion, the extent of distraction of the torn labrum, and the external rotation angle. The sensitivity, specificity, and diagnostic accuracy of MR arthrograms for determining SLAP lesion were assessed in each position. For the arthroscopically confirmed group, the diagnosis of SLAP lesion and the extent of distraction about the tear were compared between neutral and ER positions by Fisher's exact test and the paired t-test. The correlation between the external rotation angle and the diagnosis of SLAP lesion, and between the external rotation angle and the differences in the extent of distraction were evaluated in the ER position using the ANOVA test.

RESULTS

Sensitivity and diagnostic accuracy of MR arthrography for SLAP lesion increased from 64.4% and 71.0% in the neutral position to 78.5% and 81.9% in the ER position, respectively, without change of specificity, which was 93.6% in both positions. The diagnosis of SLAP lesion was changed from negative to SLAP lesion in 16.0% of the arthroscopically confirmed group. Mean difference in the extent of distraction about the tear was 0.69 mm (range -1.40 ∼ 6.67 mm), which was statistically significant. There was no relationship between the external rotation angle and the diagnosis of SLAP lesion, and between the external rotation angle and the differences in the extent of distraction.

CONCLUSION

Shoulder MR arthrography with additional ER positioning helps in the diagnosis of SLAP lesion and provides information about the displaceability of the torn labrum.