Computed tomography (CT) arthrography of shoulder instabilities in athletes

Sixty professional and recreational athletes underwent CT arthrography of the shoulder for evaluation of suspected shoulder joint derangement. These athletes, 46 males and 14 females ranging in age from 15 to 60 years (mean, 32 years), all had persistent pain that interfered with their sports activity and was resistant to conservative treatment. Seventeen patients had shoulder instability based on clinical manifestations and CT arthrographic findings. An additional five patients, also based on clinical manifestations and CT arthrographic findings, were considered to have an unobtrusive degree of anterior joint laxity. Patients with anterior instability (20 cases) all had an anteroinferior tear or detachment of the glenoid labrum, as well as some violation of the insertion of the joint capsule onto the scapula. Those with posterior instability (two cases) had a combination of labral and capsular tears. Two other major patterns of labral tears, both unaffiliated with shoulder instability, were identified. These included total or partial detachment of superior segments of the labrum, and anterior labral tears at the midglenoid level. Moreover, various degrees of labral attenuation (or, less often, enlargement), osteophyte formation, and alterations in articular cartilage were observed. Surgical correlation was obtained in 25 patients, with 95% accuracy of CT arthrographic findings. CT arthrography is a minimally invasive and highly accurate technique for investigation of glenohumeral derangement. Specifically, the extent of pathologic changes associated with instability can be determined and differentiated from other intraarticular causes of incapacity, such as labral tears caused by throwing, or degenerative changes.     

肩盂肱关节不稳的CT关节造影表现

目的　总结分析盂肱关节不稳在CT关节造影上的表现。方法　 16例经关节镜手术检查证实病例 ,对盂唇撕裂 ,关节囊撕脱 ,关节盂骨折等在CT关节造影上表现特点进行总结分析。结果　关节内损伤包括盂唇撕裂 ,见盂唇内有造影剂充盈 ;关节盂唇软骨剥脱 ,正常关节软骨三角形结构消失 ,骨性关节盂裸露于关节囊内 ;关节囊撕脱 ,表现有关节囊腔扩大 ,关节囊附着点位置改变等 ;以及骨性关节盂缘骨折 ,肱骨外上方压缩骨折等。结论　肩盂肱关节CT造影对比性好 ,断层图像无重叠 ,可清晰显示出关节内损伤 ,是肩盂肱关节不稳的一种有效准确的检查方法     

Capsulo-labro-ligamentous lesions of the shoulder: evaluation with MR arthrography

PURPOSE: The aim of the study was to analyse the accuracy of MR arthrography in the evaluation of capsulo-labro-ligamentous lesions of the shoulder in patients with glenohumeral joint instability. MATERIALS AND METHODS: From 1999 to 2001 fifty-eight patients with glenohumeral joint instability were studied by MR arthrography. Twenty-seven patients underwent surgical repair: 11 by arthroscopic and 16 by arthrotomic approach. All shoulder evaluations were performed with T1 and T2 weighted axial, coronal and sagittal oblique images, before and after intra-articular injection of gadolinium contrast. RESULTS: Forty capsulo-ligamentous lesions (including 14 capsular ruptures with extravasation of the contrast medium) were detected by MR arthrography. Fifty-two labral tears (36 of the anterior, 13 of the superior and 3 of the posterior glenoid labrum) were identified: 11 out of 52 were not recognized before gadolinium contrast injection. Five rotator cuff tears were identified, one of which was not shown in the pre-injection examination. Surgical results confirmed the MR arthrographic findings in 25/27 patients. In one case MR arthrography did not recognize a SLAP lesion; in another case it identified a tear of the capsule but not of the glenoid labrum. CONCLUSIONS: In many cases of subacute glenohumeral joint lesions with intracapsular fluid, MR may accurately evaluate capsulo-labral-ligamentous lesions. Indeed, the examination of lesions is limited by the absence of the natural contrast determined by fluid; in such cases, intra-articular injection of gadolinium contrast is necessary. MR arthrography evaluates the degree of capsulo-labro-ligamentous tears and may guide the surgical approach.     

Shoulder MR arthrography: which patient group benefits most?

OBJECTIVE: We sought to compare the diagnostic accuracy of conventional MRI versus MR arthrography of the shoulder in the assessment of high-performance athletes (professional baseball players) and to compare our findings in these patients with the conventional MRI and MR arthrographic findings in an age-matched control group of nonprofessional athletes. MATERIALS AND METHODS: Conventional MRI and MR arthrographic examinations of the shoulder in 20 consecutive professional baseball players with shoulder pain were reviewed retrospectively by two musculoskeletal radiologists in consensus. These interpretations were compared with retrospective consensus interpretations of conventional MRI and MR arthrographic examinations of the shoulder obtained in a control group of 50 consecutive nonprofessional athletes with shoulder pain. MR images were assessed for full- or partial-thickness supraspinatus tendon tears, superior labral anteroposterior (SLAP) tears, and anterior or posterior labral tears. RESULTS: In the 20 consecutive professional athlete patients, two full-thickness and six partial-thickness undersurface supraspinatus tendon tears were seen on MR arthrography but not seen on conventional MRI as well as six SLAP tears, two anterior labral tears, and one posterior labral tear. Three patients had both SLAP tears and full- or partial-thickness supraspinatus tendon tears. Of 14 patients with findings on MR arthrography that were not seen on MRI, 11 had arthroscopic correlation. In all 11, arthroscopic findings confirmed findings on MR arthrography. In the group of 50 nonprofessional athlete patients, five had additional findings on MR arthrography not seen on conventional MRI: two anterior labral tears, two partial-thickness supraspinatus tendon tears, and two SLAP tears. One patient had both a partial-thickness supraspinatus tendon tear and a SLAP tear seen on MR arthrography. The five patients with additional findings on MR arthrography had arthroscopy. In all five, arthroscopic findings confirmed the findings on MR arthrography. CONCLUSION: MR arthrography is considerably more sensitive for detection of partial-thickness supraspinatus tears and labral tears than conventional MRI. MR arthrography showed injuries in addition to those seen on conventional MRI in 14 of 20 patients in the high-performance athlete group. These results suggest high-performance athletes may be a subgroup of patients for whom MR arthrography yields considerably more diagnostic information than conventional MRI.     

CT空气—碘水双对比造影对肩关节不稳定诊断的意义

目的：探讨ＣＴ空气－碘水双对比造影对诊断肩关节不稳定的临床意义。材料与方法：８例患者做肩前穿刺，分别注入７６％泛影葡胺４ｍｌ和过滤空气１０ｍｌ，在全身ＣＴ机上行肩关节扫描。结果：所有患者气－碘双对比造影ＣＴ表现均与术中所见一致。主要特征为：（１）盂唇前部变钝、撕脱、游离；（２）关节囊前部撕脱或者关节囊破裂；（３）关节囊松弛、囊腔扩大。结论：ＣＴ气－碘双对比造影可以明确诊断肩关节不稳定，并为肩关节不稳定的解剖修复提供重要的影像学信息。     

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.     

Imaging techniques for the evaluation of glenohumeral instability

The ability to image lesions associated with glenohumeral instability has evolved significantly over the past 2 decades. In the past, several imaging techniques ranging from conventional radiography to computerized axial arthrography and, most recently, to magnetic resonance imaging have been used to depict various labral abnormalities. In most instances, conventional radiography remains the initial imaging study for evaluating the patient with persistent shoulder pain and instability. Recently, however, magnetic resonance arthrography has been firmly established as the imaging modality of choice for demonstrating specific soft tissue abnormalities associated with glenohumeral instability. This article will review the role of various imaging modalities including conventional radiography, conventional arthrography, computerized axial arthrography, magnetic resonance imaging, and magnetic resonance arthrography. Emphasis will be placed on the role of magnetic resonance arthrography as it pertains to the lesions associated with glenohumeral instability. A thorough discussion of the appearance of normal anatomic structures, anatomic variations that mimic abnormality, and the various lesions associated with glenohumeral instability will be provided.     

Schultergelenkinstabilität

Shoulder instability is a common clinical feature leading to recurrent pain and limited range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation.Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex.The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions.The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging.     

A prospective comparison study of double contrast computed tomography (CT) arthrography and arthroscopy of the shoulder

Thirty consecutive patients who underwent double contrast CT arthrography prior to shoulder arthroscopy were prospectively studied. Results from both studies were recorded with the radiologist blinded to the arthroscopic findings when making the final CT reading. The sensitivity, specificity, and accuracy, respectively, of CT arthrography findings compared to arthroscopy were 50%, 100%, 96% for rotator cuff; 66%, 100% 96% for bicipital labral complex; 100%, 100%, 100% for loose bodies; 50%, 100% 93% for Hill-Sachs lesions; 90%, 73%, 83% for anterior labral defects; and 100%, 100%, 100% for posterior labral defects. We conclude that shoulder arthroscopy accurately delineates abnormalities of the anterior and posterior labrum, bicipital labral complex, rotator cuff, joint synovium, and humeral head. CT arthrography accurately delineates capsular redundancy, loose bodies, hardware around joints, and bony glenoid rim abnormalities.     

SLAP lesions of the glenoid labrum: CT arthrographic and arthroscopic correlation.

Tears in the superior part of the glenoid labrum in the anterior and posterior directions (SLAP, superior labrum anterior, posterior) result from injuries that place excessive stress on the tendon of the long head of the biceps brachii muscle. The intimate relationship of the tendon and the superior glenoid labrum promotes injury to the latter structure. Four types of SLAP lesions are seen at arthroscopy. Images from 17 patients with surgically proved SLAP lesions who had undergone preoperative computed tomographic (CT) arthrography were retrospectively reviewed to evaluate the value of CT arthrography in the detection and accurate depiction of these labral injuries. The authors compared the findings at videotaped arthroscopic surgery with those from CT arthrography and found that abnormalities of the labral-capsular apparatus could be detected with CT arthrography in 16 of the 17 patients. Furthermore, the CT arthrographic criteria developed during this review helped determine the type of tear in 15 of the 17 patients. CT arthrography appears to be useful in the evaluation of patients with suspected SLAP lesions.     

Interobserver variation in reporting CT arthrograms of the shoulder

Computed tomography (CT) arthrography of the shoulder is an imaging modality of great diagnostic accuracy with regard to glenohumeral instability and in particular labral lesions. Interpretation of the scans is made difficult by the frequent occurrence of normal anatomic variants and the complexity of injuries to the bone and soft tissues. We selected a continuous sample of 50 CT arthrograms of the shoulder and they were reported by two consultant musculoskeletal radiologists. The results were collated and analysed for the level of agreement. Hill-Sachs showed Kappa (K) statistic to be 0.37 (fair agreement), soft tissue Bankart 0.32 (fair agreement), bony Bankart 0.61 (substantial agreement), anterior capsular laxity 0.41 (moderate agreement) and glenohumeral osteoarthritis 0.20 (slight agreement). All the results were significant with a p value of <0.05. Nine (18%) of the 50 scans were in complete agreement. The results demonstrate that there can be considerable interobserver variation (IOV) in the reports of a CT arthrogram of a shoulder. They highlight the potential difficulties in reporting such images and suggests ways in which the report could be more focussed to provide a clinically reliable report and one which matches the surgical findings accurately.     

MR arthrography of the labral capsular ligamentous complex in the shoulder: imaging variations and pitfalls

OBJECTIVE: Using MR arthrography, we examined normal anatomy, anatomic variations, and pitfalls of imaging the labral capsular ligamentous complex in the asymptomatic shoulder. SUBJECTS AND METHODS: We obtained 108 MR arthrograms of the glenohumeral joint in 95 asymptomatic volunteers with axial (108 shoulders) and oblique coronal (56 shoulders) images. We examined labral shape, patterns of capsular insertion, presence or absence of glenohumeral ligaments, and pitfalls of imaging. Our patients were men (auxiliary policemen) between 19 and 24 years old (mean age, 21 years). RESULTS: The shapes of labra were triangular (anterior part, 64%; posterior part, 47%), round (17%; 33%), flat (2%; 17%), cleaved (11%; 1%), notched (3%; 0%), or absent (2%; 2%). Using the system of Mosely and Overgaard, the anterior capsular insertion was type 1 in 63% of shoulders, type 2 in 20%, and type 3 in 17%; the posterior capsular insertion was type 1 in 60% of shoulders, type 2 in 31%, and type 3 in 9%. The superior and inferior glenohumeral ligaments were present in 99% of shoulders, but the middle glenohumeral ligament was present in only 79%. We also detected many pitfalls of MR imaging in identifying findings such as the undercutting of the labrum by cartilage (32% of shoulders), prominent axillary folds (46%), sublabral holes (7%) or recesses (33%), Buford complexes (2%), and sulci between the biceps tendon and superior labrum (30%). CONCLUSION: Knowledge of normal anatomy and anatomic variations of the labral complex is important for the examination of the shoulder with MR arthrography.     

Multimodality imaging of the postoperative shoulder

Multimodality imaging of the postoperative shoulder includes radiography, magnetic resonance (MR) imaging, MR arthrography, computed tomography (CT), CT arthrography, and ultrasound. Target-oriented evaluation of the postoperative shoulder necessitates familiarity with surgical techniques, their typical complications and sources of failure, knowledge of normal and abnormal postoperative findings, awareness of the advantages and weaknesses with the different radiologic techniques, and clinical information on current symptoms and function. This article reviews the most commonly used surgical procedures for treatment of anterior glenohumeral instability, lesions of the labral-bicipital complex, subacromial impingement, and rotator cuff lesions and highlights the significance of imaging findings with a view to detection of recurrent lesions and postoperative complications in a multimodality approach.     

Sports-related injuries of the shoulder: instability

With current technology a properly conceived imaging strategy can demonstrate instability lesions in the athlete. Plain radiographs can diagnose acute dislocations and assess successful reductions. In addition, plain radiographs can demonstrate Hill-Sachs and, more importantly for instability, osseous Bankart lesions. In the acute setting, conventional MRI nicely demonstrates labral Bankart, ligamentous. and tendonous injuries that result from dislocations and can lead to instability. In the setting of chronic instability, MR arthrography best evaluates these lesions. In the postoperative shoulder, muitislice CT arthrography may be the modality of choice, but further investigation is needed. If large series validate multislice CT arthrography for the evaluation of postoperative instability lesions, this technique may become widely used in athletes and in other populations where recurrent instability is a problem. Other imaging strategies may also find an increasing central role in evaluating shoulder instability lesions. Indirect MR arthrography, for example, may have a role in assessing these lesions in athletes . Another intriguing technology for this application is the development of high field (0.5 Tesla or greater) open magnets. In such a setting, physiological relationships in the shoulder with motion and stress may be evaluated. Such imaging may farther illuminate our understanding of the stable and unstable shoulder. Unfortunately, with all imaging modalities, whether widely used or experimental, outcomes data is Lacking. How do the various imaging modalities and strategies affect patient outcome? The answer is unknown and needs to be answered before a definitive patient work-up for shoulder instability can be established.     

Low-field MR arthrography of the shoulder joint: technique,indications, and clinical results

In the age of cost containment and urgent reductions in health care expenditures, new options have to be explored to satisfy both diagnostic requirements and economic limitations. The introduction of low-field MR systems for assessment of joint disorders seemed to be an option for lower costs. The purpose of this article is to summarize available experiences with low-field MR arthrography of the glenohumeral joint with respect to image quality and diagnostic accuracy in detecting labral and rotator cuff lesions. Up to now, there has been only a limited number of studies available dealing with low-field MR arthrography of the glenohumeral joint. They reveal that, despite a minor image quality in comparison with high-field imaging, low-field MR arthrography of the shoulder allows for sufficient evaluation of intra- and extra-articular structures in the detection of major abnormalities such as glenohumeral instability or rotator cuff disease. Furthermore, open-configured MR scanners enable kinematic studies: Besides the analysis of normal motion, pathological findings in patients with instabilities and impingement syndrome can be delineated. They further offer the possibility for performing MR imaging-guided arthrography of the shoulder. This was first described using an open C-arm scanner with a vertically oriented magnetic field so that MR arthrography may be performed in one setting. Electronic Publication     

Shoulder arthroscopy: its role in evaluating shoulder disorders in the athlete

We retrospectively reviewed 100 initial shoulder arthroscopies from a general sports medicine orthopaedic practice to determine if arthroscopy is helpful diagnostically and to see if specific lesions correlate well with specific diagnoses. Seventy-two percent of the patients in the review had glenoid labral tears. Ninety-two percent of patients who had a diagnosis of either recurrent anterior dislocation or recurrent anterior subluxation demonstrated a tear of the anterior inferior margin of the glenoid labrum. Sixty-eight percent of patients with a diagnosis of impingement demonstrated tears at the superior margin of the labrum. There was a significant difference between throwing and nonthrowing athletes. Partial rotator cuff tears were noted in 18 patients, the majority occurring in throwing athletes. Other abnormalities, such as degenerative joint changes and biceps tendon lesions, were also noted at the time of arthroscopy. A large number of glenoid labral tears found at the time of arthroscopy appeared to be associated with conditions other than instability, which may or may not affect the throwing athlete. There also appeared to be a high correlation between tears in the anterior inferior glenoid labrum and anterior instability. Arthroscopy enabled us to identify other significant information about the status of the biceps tendon or the undersurface of the rotator cuff. These are areas in which problems might otherwise have been missed. Degenerative changes of the articular surface, not apparent on plain radiographs, may also be better evaluated arthroscopically.     

MR shoulder arthrography in patients younger than 40 years of age: frequency of rotator cuff tear versus labroligamentous pathology

The purpose of this study was to compare the frequency of rotator cuff pathology versus labroligamentous pathology in patients younger than 40 years and to determine whether routine MR arthrography is justified in all patients in this age group, regardless of the clinical symptoms. The MR arthrography was carried out on 332 patients 40 years of age and younger. Two hundred and forty-three patients had clinical history of instability and possible labroligamentous pathology. Eighty-nine patients had no history or physical signs of instability and were referred for reasons other than instability, such as assessment for rotator cuff tear. In the 243 patients younger than 40 years with clinical history of potential labral pathology, 39% (95/243) showed a labral tear and 2.1% (5/243) had a full-thickness rotator cuff tendon tear. In the 89 patients with no history suggesting labral pathology, 19% (17/89) showed an unsuspected labral tear and 4.5% (4/89) had a full-thickness rotator cuff tear. These findings suggest that, regardless of the clinical indication for referral, patients aged 40 and less referred for shoulder MRI should be imaged using MR arthrography because of the significant risk that symptoms are related to unsuspected labral pathology.     

CT arthrographic patterns in recurrent glenohumeral instability

CT double-contrast arthrograms were performed on 54 shoulders in 53 patients with recurrent dislocation or subluxation to detect responsible underlying bony or soft-tissue abnormalities. Lesions of the anterior labrum in 52 (96%) of 54 cases and of the capsuloligamentous complex in 42 (78%) of 54 cases were the two most common abnormalities. There was no difference in the degree or number of labral lesions between subluxations and dislocations. However, more severe capsular lesions, subscapularis tendon tears, and widened subscapularis bursae were consistently found among patients with dislocations. Subsequent clinical, arthroscopic, and surgical findings showed that the use of CT double-contrast arthrograms resulted in improved definition of the multiple lesions associated with glenohumeral dysfunction.     

MRI of shoulder instability

The most unstable joint in the body, the glenohumeral joint is subject to many insults including microinstability, subluxation and dislocation. During the last two decades, MRI has allowed for direct visualization of many of the lesions related to instability, aiding in diagnosis as well as therapeutic planning and follow-up. This article reviews the use of MRI for shoulder instability and describes the different types of lesions associated with this disorder. Topics include technical considerations, the use of MR arthrography, normal anatomy and variants, labral and glenohumeral ligament pathology, and osseous lesions related to instability.     

The effect of isolated labrum resection on shoulder stability

The present study was initiated to determine whether glenohumeral instability and dislocation can result from isolated lesions of the glenoid labrum in an arthroscopic cadaver model. Adjacent combinations of four zones of the labrum (superior, anterosuperior, anteroinferior and inferior) were sequentially removed with a motorised shaver, taking great care to leave the capsule intact in 24 cadaver shoulders. Stability was tested before and after inserting the scope and after each resection step. Inferior stability was examined by performing an inferior drawer test. Anterior stability was evaluated with an anteroposterior drawer test in 0° of abduction and with a load-and-shift test in external rotation and 90° abduction. Labral resection of all four zones maximally resulted in a grade 1 inferior instability (<10 mm inferior translation). When two adjacent labral zones were resected, a grade 2 anterior drawer (>10 mm anterior but no medial translation) was seen in 17% of the specimens. This was seen in one more specimen after the addition of a third zone. There were no differences in the stability of the load-and-shift test after any amount of labral resection. Total labral debridement increased inferior and anterior translation, but did not allow the humeral head to dislocate. The degree of stability in the cocked-arm position, which is the most prone to dislocation, is not altered. In patients, isolated labral tears, that is, without evidence of capsuloligamentous damage, can probably be safely debrided without risking glenohumeral instability to the point of dislocation. Nevertheless, anterior translation may significantly increase when two or more zones are resected.