A comparison of magnetic resonance arthrography and arthroscopic findings in the assessment of anterior shoulder dislocations

MR arthrography of the shoulder; correlation with arthroscopy

Background

Shoulder dislocation is a common injury, particularly in the younger population. Common long-term sequelae include pain, recurrence, and shoulder arthritis. Immediate and correct diagnosis following shoulder dislocation is key to achieving optimum outcomes. Although magnetic resonance arthrography (MRA) is frequently used for diagnosing shoulder instabilities, arthroscopy is still considered the gold standard.

Purpose

This study aims to compare the diagnostic value of arthroscopy and MRA of the shoulder joint.

Materials and methods

This retrospective study estimates the sensitivity and specificity of MRA of the shoulder. Data from patients who had undergone shoulder MRA and subsequent arthroscopy during a 5-year period were retrospectively collected. Sensitivity and specificity were calculated using the arthroscopic findings as the gold standard. Moreover, diagnostic accuracy was estimated using McNemar’s test.

Results

In total, 205 cases were included from which 372 pathological findings were uncovered during the arthroscopic procedures as opposed to 360 findings diagnosed from the MRA images. The glenoid labral tear was the most common finding reported by MRA and arthroscopy. For the detection of glenoid labral tears on MRA, the sensitivity was 0.955 but with eight missed lesions; the specificity was 0.679. Capsular tears, rotator cuff tears, and cartilage lesions proved the most difficult to correctly diagnose using MRA with sensitivities of 0.2, 0.346, and 0.366, respectively.

Conclusions

With a sensitivity of 95%, MRA is a valuable diagnostic tool for assessing shoulder instabilities, particularly when diagnosing labral lesions, including bony and soft-tissue Bankart lesions. Sensitivities and specificities for other glenohumeral lesions are less convincing, however.

Detecting Rotator Cuff Tears: A Network Meta-analysis of 144 Diagnostic Studies

BACKGROUND

Many imaging techniques have been developed for the detection of rotator cuff tears (RCTs). Despite numerous quantitative diagnostic studies, their relative accuracy remains inconclusive.

PURPOSE

To determine which of 3 commonly used imaging modalities is optimal for the diagnosis of RCTs.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Studies evaluating the performance of magnetic resonance imaging (MRI), magnetic resonance arthrography (MRA), and ultrasound (US) used in the detection of RCTs were retrieved from the PubMed/MEDLINE and Embase databases. Diagnostic data were extracted from articles that met the inclusion/exclusion criteria. A network meta-analysis was performed using an arm-based model to pool the absolute sensitivity and specificity, relative sensitivity and specificity, and diagnostic odds ratio as well as the superiority index for ranking the probability of these techniques.

RESULTS

A total of 144 studies involving 14,059 patients (14,212 shoulders) were included in this network meta-analysis. For the detection of full-thickness (FT) tears, partial-thickness (PT) tears, or any tear, MRA had the highest sensitivity, specificity, and superiority index. For the detection of any tear, MRI had better performance than US (sensitivity: 0.84 vs 0.81, specificity: 0.86 vs 0.82, and superiority index: 0.98 vs 0.22, respectively). With regard to FT tears, MRI had a higher sensitivity and superiority index than US (0.91 vs 0.87 and 0.67 vs 0.28, respectively) and a similar specificity (0.88 vs 0.88, respectively). The results for PT tears were similar to the detection of FT tears. A sensitivity analysis was performed by removing studies involving only 1 arm for FT tears, PT tears, or any tear, and the results remained stable.

CONCLUSION

This network meta-analysis of diagnostic tests revealed that high-field MRA had the highest diagnostic value for detecting any tear, followed by low-field MRA, high-field MRI, high-frequency US, low-field MRI, and low-frequency US. These findings can help guide clinicians in deciding on the appropriate imaging modality.

An Ancillary Sign in the Diagnosis of Bankart and Bankart Variants in Patients With Glenohumeral Instability on Nonarthrographic Magnetic Resonance Imaging: Preglenoid Fat Thickness

OBJECTIVE

We investigated whether preglenoid fat thickness can be used as an ancillary sign for preliminary diagnosis of Bankart and its variants on nonarthrographic magnetic resonance imaging.

MATERIALS AND METHODS

Sixty-eight anterior dislocation patients were included in this retrospective study. Forty-eight patients with Bankart and its variants, as detected by arthroscopy and magnetic resonance arthrography, were included in the study group. The study group was divided into osseous Bankart, labral Bankart, Perthes, and anterior labroligamentous periosteal sleeve avulsion subgroups. Twenty patients with no detected labral pathologies by arthroscopy and magnetic resonance arthrography were included in the control group. In these patients, preglenoid fat tissue thickness at the anteroinferior portion was measured at the level of the glenoid tubercle. Thickness of preglenoid fat tissue was compared between groups with different labral pathologies and those with normal labrum.

RESULTS

The preglenoid fat tissue thickness was 2.65 ± 1.05 mm in the control group and 0.90 ± 0.59 mm in the study group (P < 0.0001). Patients with preglenoid fat tissue thinner than 1.6 mm showed a significantly increased likelihood of having Bankart and its variants in receiver operating characteristic analysis (sensitivity of 95.8% and specificity of 85%). There was no significant difference in preglenoid fat tissue thickness between the subgroups of the study group (osseous Bankart, labral Bankart, Perthes, and anterior labroligamentous periosteal sleeve avulsion).

CONCLUSION

Preglenoid fat tissue measurement can be used as an ancillary sign in the diagnosis of Bankart and Bankart variants in glenohumeral instability patients.

Magnetic Resonance Arthrographic Demonstration of Association of Superior Labrum Anterior and Posterior Lesions With Extended Anterior Labral Tears

OBJECTIVE

The objective of this study was to evaluate retrospectively the full extent of anterior labral tear and associated other labral tears on magnetic resonance arthrographic images in patients with anterior shoulder instability.

MATERIALS AND METHODS

One hundred ten magnetic resonance arthrography images with anterior labral tear were retrieved from the database of the Radiology Department. Two skeletal radiologists, one with 15 years of experience and the other with 5 years of experience analyzed the images in random order. Approval for the study was granted by the Ethics Committee. Statistical analyses were performed using SPSS software.

RESULTS

The most common localization of the labral lesions was at the anterior-inferior part of the glenoid labrum (22.7%). The anterior labral tears were commonly associate with superior labrum anterior and posterior (SLAP) lesions (45%). The most common type of SLAP lesion was type V (23.6%). Superior Labrum Anterior and Posterior type V lesion was more often detected in patients with Bankart lesion (27.7%, P = 0.043).

CONCLUSIONS

Isolated anterior labral tears are less than expected. In majority of the cases, a distinct tear at a different site of the labrum accompanies the anterior labral tear. Massive anterior labral tears are mostly seen together with SLAP lesions.

Hidden degloving rotator cuff tears secondary to glenohumeral dislocation

BACKGROUND

A rare form of rotator cuff tear (RCT) is observed secondary to glenohumeral dislocation, followed by immediate repositioning, as well as formation of scar tissue between tendons and tuberosities. Radiographic diagnosis of such "degloving" tears is problematic because they are obscured by scar tissue. We aimed to describe characteristics of degloving tears and report outcomes following their arthroscopic repair.

METHODS

Among 67 patients who underwent arthroscopic repair of RCTs secondary to shoulder dislocation, we identified 8 patients (12%) (7 anterior dislocations and 1 posterior dislocation), aged 54.5 years (range, 38-61 years), with typical characteristics of degloving tears. Preoperative imaging revealed massive 2- or 3-tendon tears in all patients (6 with a ruptured or dislocated long head of the biceps), evaluated preoperatively and at greater than 2 years, using the absolute and age- and gender-adjusted Constant scores, Subjective Shoulder Value, and Simple Shoulder Test score.

RESULTS

The absolute Constant score improved from 27 (range, 17-54) to 89 (range, 62-95). The age- and gender-adjusted Constant score improved from 31 (range, 24-57) to 97 (range, 83-100). The Simple Shoulder Test score improved from 2 (range, 0-4) to 12 (range, 9-12), while the Subjective Shoulder Value improved from 18 (range, 10-30) to 90 (range, 60-100). All patients were very satisfied (63%) or satisfied (37%).

CONCLUSION

We have described a particular form of RCT secondary to glenohumeral dislocation, resulting in degloving of the rotator cuff, followed by repositioning of tendons. The formation of scar tissue can obscure tendon tears on ultrasound, in which case further imaging is recommended to ascertain the diagnosis and avoid therapeutic delays.

Diagnosis of Superior Labrum Anterior-to-Posterior Tears by Using MR Imaging and MR Arthrography: A Systematic Review and Meta-Analysis

Purpose To evaluate the diagnostic accuracies of nonenhanced magnetic resonance (MR) imaging and MR arthrography for diagnosis of superior labrum anterior-to-posterior (SLAP) tears by using a systematic review and meta-analysis. Materials and Methods A comprehensive literature search was performed on the two main concepts of MR imaging (MR imaging, and direct and indirect MR arthrography) and SLAP tears. Inclusion criteria consisted of original studies that assessed the diagnostic accuracy of MR imaging, direct MR arthrography, and/or indirect MR arthrography for the detection of SLAP tears, by using surgical findings as the reference standard. The Quality Assessment of Diagnostic Accuracy Studies 2, or QUADAS-2 Quality Assessment of Diagnostic Accuracy Studies 2 Quality Assessment of Diagnostic Accuracy Studies 2 , tool was used to assess methodologic quality. Meta-analyses were performed that compared MR imaging studies to direct MR arthrography studies and indirect MR arthrography studies, 3-T studies to 1.5-T studies, and low-bias MR imaging studies to low-bias direct MR arthrography studies. Study variation was analyzed by using the Cochran Q test of heterogeneity and the I² statistic. Results Thirty-two studies met inclusion and exclusion criteria, including 3524 imaging examinations: 1963 direct MR arthrography examinations (23 studies), 1402 MR examinations (14 studies), and 159 indirect MR arthrography examinations (three studies). Twelve studies had low risk for bias, two had questionable risk, and 18 had high risk. Mean sensitivities of direct MR arthrography, MR imaging, and indirect MR arthrography for SLAP tear diagnosis were 80.4%, 63.0%, and 74.2%, respectively. Mean specificities of direct MR arthrography, MR imaging, and indirect MR arthrography were 90.7%, 87.2%, and 66.5%, respectively. Summary receiver operator characteristic (ROC) curve demonstrated superior accuracy of direct MR arthrography compared with those of MR imaging and indirect MR arthrography. Similar findings were observed in the low-bias subanalysis. Summary ROC curve demonstrated overall superiority of 3-T imaging, with or without intra-articular contrast material compared with 1.5-T imaging, with or without intra-articular contrast material. Significant variance was observed for MR imaging and direct MR arthrography (P < .001) studies for both mean sensitivity and specificity. Conclusion Direct MR arthrography appears to be more accurate than nonenhanced MR imaging for diagnosis of SLAP tears, whereas 3-T MR imaging with or without intra-articular contrast material appears to improve diagnostic accuracy compared with 1.5-T MR imaging with or without intra-articular contrast material. ^© RSNA, 2017 Online supplemental material is available for this article.

Arthroscopic Findings in Anterior Shoulder Instability

Background:

In the last years, basic research and arthroscopic surgery, have improved our understanding of shoulder anatomy and pathology. It is a fact that arthroscopic treatment of shoulder instability has evolved considerably over the past decades. The aim of this paper is to present the variety of pathologies that should be identified and treated during shoulder arthroscopy when dealing with anterior shoulder instability cases.

Methods:

A review of the current literature regarding arthroscopic shoulder anatomy, anatomic variants, and arthroscopic findings in anterior shoulder instability, is presented. In addition, correlation of arthroscopic findings with physical examination and advanced imaging (CT and MRI) in order to improve our understanding in anterior shoulder instability pathology is discussed.

Results:

Shoulder instability represents a broad spectrum of disease and a thorough understanding of the pathoanatomy is the key for a successful treatment of the unstable shoulder. Patients can have a variety of pathologies concomitant with a traditional Bankart lesion, such as injuries of the glenoid (bony Bankart), injuries of the glenoid labrum, superiorly (SLAP) or anteroinferiorly (e.g. anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), and accompanying osseous-cartilage lesions (Hill-Sachs, glenolabral articular disruption). Shoulder arthroscopy allows for a detailed visualization and a dynamic examination of all anatomic structures, identification of pathologic findings, and treatment of all concomitant lesions.

Conclusion:

Surgeons must be well prepared and understanding the normal anatomy of the glenohumeral joint, including its anatomic variants to seek for the possible pathologic lesions in anterior shoulder instability during shoulder arthroscopy. Patient selection criteria, improved surgical techniques, and implants available have contributed to the enhancement of clinical and functional outcomes to the point that arthroscopic treatment is considered nowadays the standard of care.

MR arthrography evaluation in patients with traumatic anterior shoulder instability

INTRODUCTION

To evaluate retrospectively the diagnostic accuracy of MR arthrography, compared with arthroscopy, in research of the glenoid labrum tear in patients with a first episode of traumatic anterior shoulder instability (TUBS).

MATERIAL AND METHODS

We retrospectively reviewed the MR arthrography shoulder images of 118 patients with a first episode of TUBS, between June 2014 and May 2016.

RESULTS

The overall accuracy of MR arthrography compared with arthroscopy of the glenoid labrum lesions was 94%, sensitivity 93%, and specificity 96%. The sensitivity of MR arthrography for Perthes lesion was 71.4%, and for ALPSA lesion, it was 91%. Slap lesion occurred in 11 out of 77 cases (9.3% of 118 cases). The Hill-Sachs lesion occurred in 48 out of 118 cases (40.7%), while the Hill-Sachs reverse lesion in 4 cases (3.4%).

CONCLUSIONS

The MR arthrography is accurate in detecting labral injuries. However, other studies are needed to assess the less frequent tear, as Perthes lesion. The presence of the Hill-Sachs lesion could provide useful information about the level of the shoulder instability.