Injury, Int. J. Care Injured 44 S3 (2013) S26–S32

Contents lists available at SciVerse ScienceDirect

Injury

journal homepage: www.elsevier.com/locate/injury

Diagnostic value of US, MR and MR arthrography in instability

Roman Pavica,b,*, Petra Margeticb, Mirta Bensicc, Renata Letica Brnadicb aSchool of Medicine, J.J.Strossmayer University, Osijek, Croatia bUniversity Hospital “Sisters of Mercy”, Clinic for Traumatology, Zagreb, Croatia cDepartment of Mathematics ,J.J.Strossmayer University, Osijek, Croatia

KEYWORDS ABSTRACT

Musculoskeletal ultrasound Introduction: The aim of our study was to compare US, conventional MRI and MR arthrography Acute and chronic shoulder instability findings in patients with anterior shoulder instability and with a clinical diagnosis of labral capsular Magnetic resonance arthrography of shoulder ligamentous complex lesion. At the same time we evaluated the accuracy of MR arthrography in the Capsulolabral complex lesion diagnosis of this lesion. Rotator cuff rupture Methods: After approval of the local Ethics Committee, our department’s Trauma Registry from July 2008 up to February 2012 was retrospectively reviewed to identify all eligible patients. Eligibility criteria included: 1) history of acute or chronic shoulder instability (more than three dislocations over a period of more than two months); 2) diagnosis of labroligamentous lesion. All patients were investigated with plain radiographs, Ultrasound Scans (US), Magnetic Resonance Imaging (MRI) and MR arthrography. Finally, all patients underwent an arthroscopy that confirmed the diagnosis. Results: A total of 200 consecutive patients who met the inclusion criteria were included in this study. The mean age was 39 years (range 15 to 83); 147 were male and 133 involved the right shoulder. Chronic instability was documented in 133 patients, whereas acute instability was documented in 67 patients. We detected a statistically significant difference between US and MR arthrography in SLAP (Superior Labrum Anterior to Posterior) lesions (Type II, III and IV), in Bankart lesions, in glenohumeral lesions (superior, middle, anterior-inferior and anterior inferior glenohumeral ligament) in Hill-Sachs lesions, in diagnosing internal subacromial impingement and in normal findings. MR arthrography was superior to the US. A statistically significant difference was evident between MRI and MR arthrography findings in SLAP lesions (III and IV Type lesions), in glenohumeral ligament lesions (anterior inferior and posterior inferior glenohumeral ligament), in partial rotator cuff ruptures and in normal findings. MR arthrography diagnosed this lesion better than MRI without contrast. We also found a statistically significant difference between US and MRI findings in SLAP Type II lesions, in partial rotator cuff ruptures, in Hill-Sachs lesions and in diagnosing internal subacromial impingement. Conclusion: The US scan is a valuable diagnostic technique for rotator cuff complete or incomplete ruptures. For evaluating Hill-Sachs lesions or bony Bankart lesions, MRI is more accurate. In the case of labral capsular ligamentous complex lesions, MR arthrography is superior. © 2013 Elsevier Ltd. All rights reserved.

Introduction instability is defined as the persistent inability of the soft tissues to keep the humeral head congruent into the .1–4 Shoulder instability represents a common condition primarily The stability of the glenohumeral depends on the affecting young active people and especially athletes. It occurs stabilizing musculotendinous structures of the rotator cuff and when the humeral head is forced out of the glenoid fossa. This most of the muscles of the shoulder girdle. The glenoid labrum can be the result of a sudden injury or from overuse activities also plays an important role in shoulder stability by providing of the . Once the soft tissues (, tendons, the fibrous attachment of the glenohumeral ligaments and and muscles) supporting the shoulder become loose or torn, the capsule to the glenoid rim.5 shoulder joint becomes prone to dislocations. Chronic shoulder According to the injured anatomical structures, several distinct pathological conditions have been described. Because of the complexity of the anatomy of the shoulder joint, the diagnosis and management of these conditions can be challenging. * Corresponding author at: Clinic of Traumatology Zagreb, Draskoviceva 19, 10 000 Zagreb, Croatia. Tel. 00385 98 9330 746 SLAP lesion represents an injury of the superior labrum, at E-mail address: [email protected] (R. Pavic). the point where the tendon of the biceps muscle inserts on the

0020-1383/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. R. Pavic et al. / Injury, Int. J. Care Injured 44 S3 (2013) S26–S32 S27

Fig. 1. MR arthrography, left shoulder, coronal plane, fibrous with Fig. 2. MR arthrography, left shoulder, transversal plane, intact scapular is loose intraarticular chondral body. stripped medially resulting in incomplete avulsion of the labrum from the glenoid margin - Perthes lesion. labrum and extends anteriorly and posteriorly. It is diagnosed when contrast media interposed between superior and anterior glenoid labrum oriented laterally towards the biceps brachii tendon insertion.4 Type I is characterized by marked fraying of the free edge of the superior labrum. Type II occurs when the labral-bicipital complex is avulsed from the glenoid. Type III is a displaced bucket handle tear of the superior labrum with an intact biceps anchor and Type IV is a bucket handle tear of the superior labrum, with extension into the fibers of the biceps tendon. The classic Bankart lesion is defined as a defect of the capsulolabral complex at the site of the inferior glenohumeral ligament (Figure 1). Its variants include: Perthes lesion (Figure 2), anterior labral periosteal sleeve avulsion (ALPSA) (Figure 3), humeral avulsion of the glenohumeral ligament (GLAD) (Figure 4), bony humeral avulsion of the glenohumeral ligament and the floating anteroinferior glenohumeral ligament (HAGL). Any of these lesions can be associated with glenolabral articular disruption.6 In Perthes lesions, the scapular periosteum remains intact but is stripped medially resulting in incomplete avulsion of the labrum from the glenoid margin, whereas in Bankart lesions, the scapular periosteum is torn. In ALPSA lesions, the labrum, Fig. 3. MR arthrography, left shoulder, transversal plane, ALPSA lesion where capsule and ligaments are medially displaced, inferiorly rotated labrum, capsule and ligaments are medially displaced, Hill-Sachs lesion. and fibrosed. In GLAD lesions the anterior glenoid labrum is partially torn with an adjacent articular cartilage chondral defect in clinically stable patient. Hill-Sachs lesion is an impacted after intra-articular injection of contrast media and subsequent fracture of dorsolateral aspect of the humeral head with/without distension of capsule.10–16 changes in intensity of adjacent bone (Figure 5). The criteria The aim of our study was to compare US, conventional MRI for defining a ligamentous lesion are: rupture, thickness and and MR arthrography findings in patients with anterior shoulder changing of intensity of the ligament. instability and with a clinical diagnosis of labral capsular Many methods have been described in the literature ligamentous complex lesion. At the same time we evaluated the for diagnosing shoulder pathology. These include standard accuracy of MR arthrography in the diagnosis of this lesion. radiograms, conventional arthrotomography, ultrasound, CT arthrography and MR imaging.7 Materials and methods For the evaluation of rotator cuff injuries, ultrasound (US) and magnetic resonance imaging (MRI) are considered to be the most After approval of the local Ethics Committee, our department’s accurate. MRI however, is more universally accepted although it Trauma Registry from July 2008 up to February 2012 was can be limited in evaluating partial tears of the rotator cuff.8,9 retrospectively reviewed to identify all eligible patients. On the other hand, labral capsular ligamentous complex lesions Eligibility criteria included: 1) history of acute or chronic can be diagnosed by MRI but subtle lesions are better visualised shoulder instability (more than three dislocations over a period S28 R. Pavic et al. / Injury, Int. J. Care Injured 44 S3 (2013) S26–S32

Fig. 4. MR arthrography, left shoulder, tranversal plane, humeral avulsion of the glenohumeral ligament - GLAD lesion. Fig. 5. MR arthrography, left shoulder, transversal plane, impacted fracture of dorsolateral aspect of the humeral head without changes in intensity of adjacent of more than two months); 2) diagnosis of labroligamentous bone - Hill-Sachs lesion. lesion. Details including patient age, gender, mechanism of injury, clinical examination, finding of imaging modalities (standard radiograms, US, conventional MRI and MR arthrography), were recorded and analysed.

Imaging

US were performed on a SHIMADZU 2200 using a 7-15 MHz linear probe. Patients were examined according to the accepted standard Musculoskeletal Ultrasound Technical Guidelines published by the European Society of Musculoskeletal Radiology.17 Conventional MRI and MR arthrography were performed by a 1.0-T system (Magnetom Expert; Siemens, Erlangen, Germany) and a dedicated phased-array shoulder coil (Siemens). Patients underwent imaging with the in neutral position. Conventional MRI was done using a dedicated shoulder coil, 3 mm slice thickness, 12-16 cm FOV and 512 x 512 matrix; the following sequences were used: oblique coronal proton density, axial proton density, oblique coronal T2 with fat saturation and oblique sagittal T2 with fat saturation. Injection of contrast media for MR arthrography was performed with a posterior Fig. 6. MR arthrography, right shoulder, coronal plane, SLAP lesion Type III - approach by radiologists with at least 2 years of experience in displaced bucket handle tear of the superior labrum with an intact biceps anchor. arthrography. Intra-articular positioning of the needle (22-gauge Partial rotator cuff rupture. needle) was confirmed by means of injection of 5 ml of iodinated contrast media (iopromide, Ultravist 300; Schering Berlin, Germany). Once the needle is in position 0.1 ml of gadopentetate A shoulder arthroscopy was finally performed to all patients, dimeglumine (Magnevist; Schering) diluted with 20 ml saline where the definitive diagnosis was made. was injected. After injection of contrast material, the patient was escorted to the MR imaging room. MR imaging was performed Statistical Analysis within 45 minutes after contrast agent injection. Coronal oblique, sagittal oblique and transverse T1-weighted, spin-echo To test for marginal homogeneity, the exact McNemar test sequences and a coronal oblique T2-weighted fast spin-echo was used (small sample size). A p-value of less than 0.05 was pulse sequence were performed. For the image analysis of the MR considered as statistically significant. arthrograms and the classification of labroligamentous lesions, pre-established criteria were applied (Figures 6 and 7).18–21 Results All patients were consented before undergoing the procedure and all images were evaluated by a single experienced A total of 200 consecutive patients who met the inclusion musculoskeletal radiologist (>12 years’ experience in criteria were included in our study. The mean age was 39 years musculoskeletal radiology). (range 15 to 83 years); 147 were male and 133 involved the right R. Pavic et al. / Injury, Int. J. Care Injured 44 S3 (2013) S26–S32 S29

shoulder. Chronic instability was documented in 133 patients, whereas acute instability was documented in 67 patients. All patients had plain radiographs, US scans and conventional MRIs. Plain radiographs were reported as normal in all patients, whereas the US scans revealed rotator cuff ruptures in 80 patients (complete in 27 patients and partial in 54 patients) (Table 1). MRI scans identified 20 patients with SLAP lesions (Type II: 16 patients; Type II: 4 patients), while for 67 patients the report was unremarkable. The MR arthrograms revealed a labroligamentous lesion in 159 patients and an isolated Hill- Sachs lesion in 4 patients (Table 2). We then compared each the treatment modalities using the exact McNemar test (Tables 3, 4 and 5).

Discussion

For the evaluation of the rotator cuff tears, both MRI and ultrasound are regularly used in clinical practice. Kelly et al. reported that US and MRI are both useful in diagnosis of rotator cuff tears, although no method was considered superior.22 In our study we didn’t find any statistically significant difference between these techniques in diagnosing incomplete rotator cuff rupture; however, there was a statistically significant difference Fig. 7. MR arthrography, right shoulder, transversal plane, SLAP lesion Type IV - with regards to partial rotator cuff rupture. When we analysed bucket handle tear of the superior labrum, with extension into the fibers of the the detection of labrum and ligamentous defects (SLAP Type biceps tendon. II lesion and in Hill-Sachs lesion), we found a statistically significant difference between the two techniques (Table 5). Shahabpour et al. compared the different diagnostic imaging Table 1 methods for assessing the soft tissues and articular pathology Results of ultrasound findings of the shoulder23. He concluded that all the imaging modalities Diagnosis Ultrasound (number of participants) were less accurate for partial-thickness tears. Nevertheless, Complete rotator cuff rupture 27 when comparing them he found that MR arthrography and US Partial rotator cuff rupture 54 are more accurate in detecting these defects, compared to MRI. Hill-Sachs lesion 17 Conversely, for SLAP lesions (Type II, III and IV), Bankart lesions, Osseous Bankart lesion 1 glenohumeral ligament lesions (superior, middle, anterior- Degenerative changes 36 Negative 65 inferior and posterior-inferior glenohumeral ligaments) and Hill- Total 200 Sachs lesions, the MR arthrography was superior to US (Table 3). MRI represents a more universally accepted imaging modality, Bankart lesion: injury of the anterior (inferior) glenoid labrum of the shoulder due to repeated (anterior) shoulder dislocation; Hill-Sachs lesion: cortical because it is easier to perform and can be evaluated by more depression in the posterolateral head of the humerus bone. than one radiologist. On the other hand, US is more challenging

Table 2 Results of conventional MR and MR arthrography findings

Diagnosis Conventional MR (number of participants) MR arthrography (number of participants)

SLAP lesion 16 - Type II 2 - Type I 4 - Type III 21- Type II 45 - Type III 43 - Type IV ALPSA lesion 1 4 GLAD lesion 0 1 Bankart lesion 5 -bony lesion 15 - fibrous lesion Perthes lesion 0 6 Glenohumeral lesion (GHL) 1 - superior GHL 11 - superior GHL 2 - middle GHL 13 - middle GHL 5 - anterior inferior GH 40 - anterior inferior GHL 2 - posterior inferior GHL 21 - posterior inferior GHL Rotator cuff rupture 27 - complete rupture 27 - complete rupture 58 - partial rupture 61 - partial rupture Hill-Sachs lesion 40 4 Degenerative changes 85 86 Negative findings 67 5

ALPSA: anterior labral periosteal sleeve avulsion; Bankart lesion: injury of the anterior (inferior) glenoid labrum of the shoulder due to repeated (anterior) shoulder dislocation; GLAD: anterior-inferior labral tear associated with an injury to the glenoid articular cartilage; Hill-Sachs lesion: cortical depression in the posterolateral head of the humerus bone; MR, magnetic resonance; Perthes lesion: anterior glenohumeral injury in which the anterior labrum is lifted from the edge of the glenoid along with a sleeve periosteum which is displaced medially, off the underlying bone; SLAP: superior, anterior-posterior labral lesion. S30 R. Pavic et al. / Injury, Int. J. Care Injured 44 S3 (2013) S26–S32

Table 3 Comparison of US and MR arthrography findings in 200 patients

US findings

Yes, US found No, US found Type of lesion MR arthrography findings lesion no lesion McNemar exact test p-value

SLAP Type II (n) Yes, MRA found lesion 0 21 <0.001 No, MRA found no lesion 0 179 SLAP type III (n) Yes, MRA found lesion 0 45 <0.001 No, MRA found no lesion 0 155 SLAP type IV (n) Yes, MRA found lesion 0 43 <0.001 No, MRA found no lesion 0 157 Bankart lesion (n) Yes, MRA found lesion 0 20 <0.001 No, MRA found no lesion 0 180 Superior glenohumeral ligament lesion (n) Yes, MRA found lesion 0 11 <0.001 No, MRA found no lesion 0 189 Middle glenohumeral ligament lesion (n) Yes, MRA found lesion 0 13 <0.001 No, MRA found no lesion 0 187 Anterior inferior glenohumeral ligament lesion (n) Yes, MRA found lesion 0 40 <0.001 No, MRA found no lesion 0 160 Posterior inferior glenohumeral ligament lesion (n) Yes, MRA found lesion 0 21 <0.001 No, MRA found no lesion 0 189 Number of participants 200

Bankart lesion: injury of the anterior (inferior) glenoid labrum of the shoulder due to repeated (anterior) shoulder dislocation; MR, magnetic resonance; n, number of participants; SLAP: superior, anterior-posterior labral lesion; US, ultrasonography.

Table 4 Comparison of MR and MR arthrography findings in 200 patients

US findings

Yes, US found No, US found Type of lesion MR arthrography findings lesion no lesion McNemar exact test p-value

SLAP type III (n) Yes, MRA found lesion 4 21 <0.001 No, MRA found no lesion 0 179 SLAP type IV (n) Yes, MRA found lesion 0 45 <0.001 No, MRA found no lesion 0 155 Anterior inferior glenohumeral ligament lesion (n) Yes, MRA found lesion 5 35 <0.001 No, MRA found no lesion 0 160 Posterior inferior glenohumeral ligament lesion (n) Yes, MRA found lesion 2 19 <0.001 No, MRA found no lesion 0 179 Partial rotator cuff rupture (n) Yes, MRA found lesion 58 13 <0.001 No, MRA found no lesion 0 129 Number of participants 200

MR, magnetic resonance; n, number of participants; SLAP: superior, anterior-posterior labral lesion; US, ultrasonography.

Table 5 Comparison of US and MR findings in 200 patients

US findings

Yes, US found No, US found Type of lesion MR arthrography findings lesion no lesion McNemar exact test p-value

SLAP type II (n) Yes, MR found lesion 0 16 <0.001 No, MR found no lesion 0 184 Partial rotator cuff rupture (n) Yes, MR found lesion 54 4 <0.001 No, MR found no lesion 0 142 Hill-Sachs lesion (n) Yes, MR found lesion 17 23 <0.001 No, MR found no lesion 0 160 Number of participants 200

Hill-Sachs lesion: cortical depression in the posterolateral head of the humerus bone; MR, magnetic resonance; n, number of participants; SLAP: superior, anterior-posterior labral lesion; US, ultrasonography. to perform and is operator dependent. For assessing the glenoid intensity on axial images was a helpful finding in diagnosing labrum, the origin and course of glenohumeral ligaments, tears type II SLAP lesions. This confirms our findings, where all of the of the glenoid labrum, the relationship of the labrum with the 21 patients with SLAP lesions had an AP extension of high signal bicipital tendon and glenohumeral ligaments, MR arthrography intensity on axial images (Table 6). is superior to conventional MR imaging. Waldt et al. evaluated the accuracy of MR arthrography in Jin et al. described the findings of Type II SLAP lesions in MR classifying the anteroinferior labroligamentous injuries.6 He arthrography.24 They assessed 57 patients, of which 34 patients reported that MR arthrography was accurate both for acute had SLAP Type II lesions and 23 patients had a sub-labral recess. and chronic anteroinferior labroligamentous injuries, a finding They concluded that anteroposterior (AP) extension of high signal similar to ours (Table 6). R. Pavic et al. / Injury, Int. J. Care Injured 44 S3 (2013) S26–S32 S31

Table 6 Comparison of MR arthrography findings in various studies

MR arthrography findings US findings

SLAP GLAD ALPSA Bankart Perthes rotator cuff Hill-Sachs Author lesion lesion lesion lesion lesion rupture lesion Other findings

Bencardino, 200035 19 3 B 1 3 inferior gleno-humeral 52 participants T I - 16 ligament lesion – 8 T II - 9 chondral lesion – 5 T III -1 posterior labral tear -1 T IV - 3 normal findings - 12 Jin, 200533 T II - 34 superior labral recesus - 23 57 participants Waldt, 200534 3 22 44 F 12 Non-classifiable. lesions 104 participants (injuries could not be assigned to any categories) - 23 Amin, 201236 22 1 F 1 normal findings – 10 34 participants Li, 201237 8 32 39 F 7 67 78 participants Jana, 201238 T I - 1 29 F 30 participants Pavic, 2012 111 1415 F6 27 - complete 41 27 complete and 200 participants T I – 2 5 B 71- partial 54 partial T II – 21 rotator cuff rupture T III – 45 17 Hill-Sachs lesion T IV – 43 1 bony Bankart lesion

ALPSA: anterior labral periosteal sleeve avulsion; Bankart lesion: injury of the anterior (inferior) glenoid labrum of the shoulder due to repeated (anterior) shoulder dislocation; Bony Bankart: Bankart lesion that includes a fracture of the anterior-inferior glenoid cavity of the scapula bone; B: bony lesion; F: fibrous lesion; GLAD: anterior-inferior labral tear associated with an injury to the glenoid articular cartilage; Hill-Sachs lesion: cortical depression in the posterolateral head of the humerus bone; Perthes lesion: anterior glenohumeral injury in which the anterior labrum is lifted from the edge of the glenoid along with a sleeve periosteum which is displaced medially, off the underlying bone; MR, magntic resonance; SLAP: superior, anterior-posterior labral lesion; T I: Type I; T II:Type II; T III: Type III; T IV: Type IV; US, ultrasonography.

Bencardino et al. concluded in their study that MR arthro- his experience.11 Generally, ample experience is required to graphy is a useful and accurate technique in the diagnosis of SLAP distinguish between a labral lesion and a normal anatomical lesions of the shoulder. More specifically, it provided pertinent variant, small partial rupture of rotator cuff or ligamentus lesion. pre-operative information with regards to the exact location In our case series, a single experienced radiologist reported all of tears and grade of involvement of the biceps tendon.25 Out the MRIs. of 52 patients involved in their, 19 SLAP lesions were reported. US scans were performed in all of our patients. Our results Our study agrees with their results with regards to the accuracy correspond to results in literature.6,7 The topography and extend of the MR arthrography, whereas out of 200 patients, 111 were of the lesion could be clearly visualised as well, which represents diagnosed with a SLAP lesion. critical information in planning the arthroscopic treatment. In Amin et al. investigated the MR arthrography sensitivity and detail, detail pre-operative assessment of the extension of the concluded that it is a sensitive, minimally invasive technique labral tear assists with planning the suture anchor placements that can be utilised for the diagnosis and grading of SLAP lesions, and saves time during arthroscopy. ALPSA lesions are also reducing the need for diagnostic arthroscopy.26 Out of 59 patients important to be diagnosed on arthrograms since they can be included in their study, 22 were diagnosed with a SLAP lesion missed during arthroscopy, particularly after chronic injuries.8 and 1 with a Bankart lesion. In our study, out of 200 patients ALPSA is indicative of a more severe trauma and recurrent included, 111 were diagnosed with a SLAP lesion and 15 with dislocation, which causes displacement of the labrocapsular Bankart lesions (Table 6). complex medially along the scapular . Li et al. suggested that MR arthrography has a higher Our study has some limitations. Because our cases were sensitivity, specificity and accuracy when compared to MRI, collected from a non-selected patient population with a history for the detection of anterior labrum lesions27, a finding similar of chronic shoulder pain and instability, no specific images were to our results. However, we detected no statistically significant obtained. In only 35 cases arthroscopy followed MR arthrography difference in diagnosing SLAP Type I and Type II with MRI, with or and confirmed MRI findings. In other cases patients went on without contrast media. Moreover, MR arthrography was found rehabilitation or they are still waiting for arthroscopy. Also, inter to be more accurate in diagnosing SLAP Type II and III lesions. observer variation was not assessed in our study because all MR Jana et al. analysed 52 patients with acute shoulder instability images were evaluated by only one musculoskeletal radiologist. and detected 30 labroligamentous lesions.28 They reported that MR arthrography yields a good correlation with arthroscopy. In Conclusion our study only 35 patients underwent arthroscopy, but there still was a good correlation with MR arthrography findings (Table 6). The US scan is a valuable diagnostic technique for rotator MRI represents a sensitive method for the prompt assessment cuff complete or incomplete ruptures. For evaluating Hill-Sachs of both bony and ligamentous injuries of the shoulder joint lesions or bony Bankart lesions, MRI is more accurate. In the case when the initial radiographs are normal. The interpretation of of labral capsular ligamentous complex lesions, MR arthrography the results however depends on the reporting radiologist and is superior. S32 R. Pavic et al. / Injury, Int. J. Care Injured 44 S3 (2013) S26–S32

Conflict of interest 15. SJ S. Labral lesions (non-instability) and SLAP lesions. New York: NY: McGraw-Hill; 1994. All authors declare they have no conflicts of interest. 16. Snyder SJ, Karzel RP, Del Pizzo W, Ferkel RD, Friedman MJ. SLAP lesions of the shoulder. Arthroscopy 1990;6:274-279. 17. Martinoli C. Musculoskeletal ultrasound: technical guidelines. Insights References Imaging. 2010;1:99-141. 18. DA; D, LL J. Arthroscopic shoulder anatomy: pathologic and surgical 1. Levine WN, Flatow EL. The pathophysiology of shoulder instability. Am J implications. New Jersey: NJ: Slack 1986. Sports Med 2000;28:910-917. 19. Kwak SM, Brown RR, Resnick D, Trudell D, Applegate GR, Haghighi P. 2. O’Connell PW, Nuber GW, Mileski RA, Lautenschlager E. The contribution of Anatomy, anatomic variations, and pathology of the 11- to 3-o’clock position the glenohumeral ligaments to anterior stability of the shoulder joint. Am J of the glenoid labrum: findings on MR arthrography and anatomic sections. Sports Med 1990;18:579-584. AJR Am J Roentgenol 1998;171:235-238. 3. Ovesen J, Nielsen S. Stability of the shoulder joint. Cadaver study of 20. Massengill AD, Seeger LL, Yao L, Gentili A, Shnier RC, Shapiro MS, et al. stabilizing structures. Acta Orthop Scand 1985;56:149-151. Labrocapsular ligamentous complex of the shoulder: normal anatomy, 4. Turkel SJ, Panio MW, Marshall JL, Girgis FG. Stabilizing mechanisms anatomic variation, and pitfalls of MR imaging and MR arthrography. preventing anterior dislocation of the glenohumeral joint. The Journal of bone Radiographics 1994;14:1211-1223. and joint surgery American volume. 1981;63:1208-1217. 21. Palmer WE, Brown JH, Rosenthal DI. Labral-ligamentous complex of the 5. Bankart AS. The pathology and treatment of recurrent dislocation of the shoulder: evaluation with MR arthrography. Radiology 1994;190:645-651. shoulder-joint. Br J Surg 1938;26:23-29. 22. Kelly AM, Fessell D. Ultrasound compared with magnetic resonance imaging 6. Waldt S, Burkart A, Imhoff AB, Bruegel M, Rummeny EJ, Woertler K. Anterior for the diagnosis of rotator cuff tears: a critically appraised topic. Semin shoulder instability: accuracy of MR arthrography in the classification of Roentgenol 2009;44:196-200. anteroinferior labroligamentous injuries. Radiology. 2005;237:578-583. 23. Shahabpour M, Kichouh M, Laridon E, Gielen JL, De Mey J. The effectiveness 7. Park YH, Lee JY, Moon SH, Mo JH, Yang BK, Hahn SH, et al. MR arthrography of of diagnostic imaging methods for the assessment of and articular the labral capsular ligamentous complex in the shoulder: imaging variations disorders of the shoulder and . Eur J Radiol 2008;65:194-200. and pitfalls. AJR Am J Roentgenol 2000;175:667-672. 24. Jin W, Ryu KN, Kwon SH, Rhee YG, Yang DM. MR arthrography in the 8. Margetic P, Pavic R. Comparative assessment of the acute injury by differential diagnosis of type II superior labral anteroposterior lesion and ultrasound and magnetic resonance. Coll Antropol 2012;36:605-610. sublabral recess. AJR Am J Roentgenol 2006;187:887-893. 9. Pavic R. Major defect to the brachial artery following blunt trauma - a five 25. Bencardino JT, Beltran J, Rosenberg ZS, Rokito A, Schmahmann S, Mota J, et al. year follow-up. Coll Antropol 2011;35:203-205. Superior labrum anterior-posterior lesions: diagnosis with MR arthrography 10. G P. [Lieber operationen bei habitueller Schulterluxationen]. Deutsch Z Chir. of the shoulder. Radiology 2000;214:267-271. 1906:199-227. 26. Amin MF, Youssef AO. The diagnostic value of magnetic resonance 11. Howell SM, Galinat BJ. The glenoid-labral socket. A constrained articular arthrography of the shoulder in detection and grading of SLAP lesions: surface. Clin Orthop Relat Res 1989:122-125. comparison with arthroscopic findings. Eur J Radiol 2012;81:2343-2347. 12. Maffet MW, Gartsman GM, Moseley B. Superior labrum-biceps tendon 27. Li HF, Liu YJ, Cheng LQ, Li ZL, Wang JL, Qi W, et al. [Diagnostic value of MRI complex lesions of the shoulder. Am J Sports Med 1995;23:93-98. and MR arthrography in the detection of injuries of anterior labrum in 13. Neviaser TJ. The anterior labroligamentous periosteal sleeve avulsion lesion: shoulder]. Zhongguo Gu Shang 2012;25:413-417. a cause of anterior instability of the shoulder. Arthoscopy 1993;9:17-21. 28. Jana M, Srivastava DN, Sharma R, Gamanagatti S, Nag HL, Mittal R, et al. 14. Neviaser TJ. The GLAD lesion: another cause of anterior shoulder pain. Magnetic resonance arthrography for assessing severity of glenohumeral Arthroscopy 1993;9:22-23. labroligamentous lesions. J Orthop Surg (Hong Kong) 2012;20:230-235.