Arthroscopic assessment of the unstable shoulder

The purpose of this study was to evaluate prospectively the findings during shoulder arthroscopy in patients with recurrent anterior instability of the gleno-humeral joint. One hundred and seventy-eight patietns who fulfilled the criteria of having had at least one documented shoulder dislocation were included in the study. The pathological findings most frequently noted at arthroscopy were: anterior glenoid labral tears (85%), ventral capsule insufficiency (80%), Hill-Sachs compression fractures (67%), glenohumeral ligament insufficiency (55%), rotator cuff tears (20%), posterior glenoid labral tears (8%), and SLAP lesions (5%). Abnormalities were noted more frequently than expected, and there were significant differences between preoperative and postoperative diagnoses. Our study has taught us that a mulitplicity of morphological changes are associated with instability of the glenohumeral joint, and that there is no single cause. The labrum and rim of the anterior inferior glenoid, for instance, showed typical abnormalities corresponding to different entities of anterior instability. In practice, this is very important, as the abnormalities visualized by imaging methods determine the surgical treatment.     

MR arthrography of the posterior labrocapsular complex: relationship with glenohumeral joint alignment and clinical posterior instability

OBJECTIVE: The purpose of our study was to investigate the relationship between tears of the posterior labrocapsular complex and glenohumeral alignment on MR arthrography and the presence and extent of posterior labrocapsular tears in patients with posterior instability. MATERIALS AND METHODS: Posterior labrocapsular tears identified on 24 MR arthrograms and surgically confirmed were evaluated for length of tear and labrocapsular avulsion. These examinations and a comparison cohort of 70 normal MR arthrograms with normal findings were also evaluated for humeral head position relative to the glenoid fossa. Medical records were reviewed for clinical diagnosis of posterior instability and history of shoulder trauma. RESULTS: The position of the humeral head relative to the glenoid was significantly more posterior in patients with posterior labral tear than in patients with a normal posterior labrum (4.9 mm versus 0.7 mm; p < 0.0001). The mean length (+/- SD) of posterior labral tear was 15.9 +/- 1.7 mm, and a direct correlation was found between tear length and posterior humeral translation (r = -0.65; p = 0.002). Posterior labral tears were significantly longer (18.6 vs 13.1 mm; p = 0.04), and posterior humeral translation was greater (6.4 vs 3.4 mm; p = 0.006) in patients with labrocapsular avulsion than in those without avulsion. Twelve (50%) of the patients with posterior labrocapsular tear had posterior instability, and 10 (83%) had a history of macrotrauma. On MR arthrography, the mean posterior humeral translation was greater (6.2 mm +/- 0.08; p = 0.019), posterior labral tears were longer (19.4 mm +/- 1.7; p = 0.0008), and labrocapsular avulsion was more common (83%; p = 0.0001) in patients with posterior instability than in patients who had a posterior labral tear but a clinically stable shoulder. CONCLUSION: Clinical posterior instability is associated with excessive posterior humeral translation, long posterior labral tears, and posterior labrocapsular avulsion.     

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。     

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.     

Biomechanics of the Bankart repair: the relationship between glenohumeral translation and labral fixation site.

The specific aim of this study was to quantify glenohumeral translations in cadaveric shoulders after repair of the superior and middle regions of a surgically created Bankart lesion and after repair of the superior, middle, and inferior regions of the same lesion. Anterior-posterior, superior-inferior, and medial-lateral translations in nine cadaveric specimens were tested with shoulders in 0 degree, 45 degrees, and 90 degrees of humeral abduction and varying degrees of humeral rotation. There was statistically significantly less anterior and inferior translation after three-site labral repair compared with after two-site labral repair, and this effect was greatest at 90 degrees of glenohumeral abduction. The decreased translations demonstrated with three-site repair emphasized the importance of careful repair of the labrum to the inferior glenoid rim during a Bankart reconstruction and suggested that failure to do so may be a contributing factor to recurrent instability after anterior shoulder reconstruction.     

The crank test,the O'Brien test,and routine magnetic resonance imaging scans in the diagnosis of labral tears

BACKGROUND: Tears of the superior labrum of the shoulder, anterior to posterior, are difficult to diagnose clinically. PURPOSE: We examined whether the crank or O'Brien tests were reliable tools for detecting glenoid labral tears. STUDY DESIGN: Nonrandomized prospective study. METHODS: Results of diagnostic shoulder arthroscopy were compared with those of the preoperative tests and magnetic resonance imaging for 65 patients who had symptoms of shoulder pain. RESULTS: The crank test result was positive in 29 patients (45%), and the O'Brien test was positive in 41 patients (63%). The crank test had a positive predictive value of 41%, was 56% specific, 46% sensitive, and had a negative predictive value of 61%. The O'Brien test had a positive predictive value of 34%, was 31% specific, 54% sensitive, and had a negative predictive value of 50%. Magnetic resonance imaging had a positive predictive value of 63%, was 92% specific, 42% sensitive, and had a negative predictive value of 83%. CONCLUSIONS: The O'Brien and crank tests were not sensitive clinical indicators for detecting glenoid labral tears and other tears of the anterior and posterior labrum. Results were often falsely positive for patients with other shoulder conditions, including impingement or rotator cuff tears.     

Arthroscopic treatment of posterior and multidirectional instability

The author can answer the three fundamental questions which were posed in the beginning of this chapter as follows: Atraumatic posterior and multidirectional laxity is attributable to capsular ligamentous laxity and can be asymptomatic initially. Over the time, repetitive subluxation of the humeral head exerts excessive rim-loading on the posteroinferior glenoid labrum which can develop into retroversion of the glenoid labrum and eventually leading to labral tears. In this stage, a patient develops shoulder pain during daily and sports activities. Besides increased translation, the diagnosis should be based on the symptoms reproduced by the jerk and Kim tests. The jerk test is a hallmark for predicting the prognosis of nonoperative treatment in posteroinferior instability. Shoulders with a painful jerk test have posteroinferior labral lesion and are unresponsive to nonoperative treatment. In these patients, early surgery may be indicated. Any successful surgical procedure should correct both the capsular laxity and the retroversion of the posteroinferior glenoid labrum. Simple capsular plication or an inferior capsular shift is insufficient for correcting the two major pathologies. Arthroscopic capsulolabroplasty restores capsular tension as well as labral height.     

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.     

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.     

Combined lesions of the glenoid labrum

Advances in shoulder arthroscopy and improved understanding of the pathoanatomy following shoulder instability have led to increased recognition of combined lesions of the glenoid labrum. Although the diagnosis of combined labral tears is often made with physical examination and magnetic resonance imaging, combined tears can be discovered intraoperatively. A high index of suspicion is necessary, especially in the setting of chronic recurrent shoulder instability or previous failed labral repair. Over a 6-year period at a military institution, combined labral repairs comprised 37% of all patients undergoing any labral repair. With accurate identification of all labral pathology and a systematic approach to labral repair, successful outcomes can be achieved.     

Comparison between Conventional MR Arthrograhphy and Abduction and External Rotation MR Arthrography in Revealing Tears of the Antero-Inferior Glenoid Labrum

Objective

To compare, in terms of their demonstration of tears of the anterior glenoid labrum, oblique axial MR arthrography obtained with the patient''s shoulder in the abduction and external rotation (ABER) position, with conventional axial MR arthrography obtained with the patient''s arm in the neutral position.

Materials and Methods

MR arthrography of the shoulder, including additional oblique axial sequences with the patient in the ABER position, was performed in 30 patients with a clinical history of recurrent anterior shoulder dislocation. The degree of anterior glenoid labral tear or defect was evaluated in both the conventional axial and the ABER position by two radiologists. Decisions were reached by consensus, and a three-point scale was used: grade 1=normal; grade 2=probable tear, diagnosed when subtle increased signal intensity in the labrum was apparent; grade 3=definite tear/defect, when a contrast material-filled gap between the labrum and the glenoid rim or deficient labrum was present. The scores for each imaging sequence were averaged and to compare conventional axial and ABER position scans, Student''s t test was performed.

Results

In 21 (70%) of 30 patients, the same degree of anterior instability was revealed by both imaging sequences. Eight (27%) had a lower grade in the axial position than in the ABER position, while one (3%) had a higher grade in the axial position. Three whose axial scan was grade 1 showed only equivocal evidence of tearing, but their ABER-position scan, in which a contrast material-filled gap between the labrum and the glenoid rim was present, was grade 3. The average grade was 2.5 (SD=0.73) for axial scans and 2.8 (SD=0.46) for the ABER position. The difference between axial and ABER-position scans was statistically significant (p<0.05).

Conclusion

MR arthrography with the patient''s shoulder in the ABER position is more efficient than conventional axial scanning in revealing the degree of tear or defect of the anterior glenoid labrum. When equivocal features are seen at conventional axial MR arthrography, oblique axial imaging in the ABER position is helpful.     

MRI of internal impingement of the shoulder

OBJECTIVE: Internal impingement is a condition that occurs in athletes in which the shoulder is put in extreme abduction and external rotation during overhead movements. During this motion, the posterior fibers of the supraspinatus tendon, anterior fibers of the infraspinatus tendon, or both can get impinged between the humeral head and the posterior glenoid. The purpose of this study was to evaluate the ability of MRI to show the findings of internal impingement of the shoulder. CONCLUSION: As opposed to our six patients with clinically and surgically diagnosed internal impingement, the control patients had isolated pathology in the rotator cuff, labrum, or humeral head. We found that the constellation of findings of undersurface tears of the supraspinatus or infraspinatus tendon and cystic changes in the posterior aspect of the humeral head associated with posterosuperior labral pathology is a consistent finding diagnostic of internal impingement.     

Normal and abnormal glenoid labrum: assessment with multiplanar gradient-echo MR imaging.

A retrospective study of magnetic resonance (MR) imaging of the glenoid labrum performed with multiplanar gradient-echo (MPGR) sequences was done to ascertain the different appearances of the normal labrum and the findings in patients with tears. MPGR images were obtained with a 1.5-T magnet in 37 shoulders of 16 healthy subjects and 19 patients with subsequent surgical evaluation. Increased intralabral signal intensity was seen in 12 of 26 normal shoulders (46%), and atypical morphology was seen in six shoulders (23%). Atypical morphology was present in eight of nine patients with labral tears. Deformity (n = 2 [22%]) and clefts (n = 2 [22%]) were seen in patients with tears. Deformity (n = 3 [12%]) and clefts (n = 1 [4%]) were occasionally seen in healthy subjects. Absence of the labrum and separation of the labrum from the glenoid cavity was present only in patients with tears; therefore, the labrum should be presumed torn in the presence of these findings. Increased intralabral signal intensity on MPGR images did not help predict labral integrity; morphologic findings were more predictive of labral tear.     

MR arthrography of the shoulder: comparison with conventional MR imaging

Twenty-three patients underwent both conventional MR imaging of the shoulder and MR shoulder arthrography for clinically suspected labral or rotator cuff abnormalities. Images obtained before and after contrast administration were studied independently, and without knowledge of clinical findings, by two radiologists for the presence of abnormalities of the glenoid labrum or rotator cuff. Results were correlated with surgical findings in all patients. Nine patients had surgically proved labral tears. MR arthrography detected all nine labral abnormalities, while six of the nine were missed on conventional MR imaging. Fourteen patients had surgically proved rotator cuff tears. MR arthrography detected 11 of the 14 tears and missed three partial tears on the bursal surface. Conventional MR imaging detected nine cuff tears and missed five tears; two of these were complete rotator cuff tears and three were partial tears of the undersurface of the rotator cuff. Our results suggest that MR arthrography enhances the accuracy of MR in the evaluation of the glenoid labrum and rotator cuff tendon.     

Magnetic resonance imaging of the glenoid labrum

Shoulder complaints are common in the athletic population. Successful treatment is dependent upon the ability to correctly identify the pathologic changes associated with a specific disorder and arrive at an accurate diagnosis. Labral abnormalities are traditionally associated with glenohumeral instability. Isolated labral tears or degenerative changes may also cause shoulder dysfunction. A reliable clinical tool to assess the status of the labrum would be useful for diagnosis and management of shoulder disorders. The magnetic resonance images of 48 shoulders that had subsequent surgical examination of their labra were reviewed with respect to labral appearance. Labra appearing as abnormal were further classified as torn, degenerative, or eroded. Surgical examination was used as the reference standard. Magnetic resonance imaging demonstrated high levels of sensitivity, specificity, positive and negative predictive values, and accuracy for evaluation of the glenoid labrum. Magnetic resonance imaging is a reliable and accurate method for depicting the status of the glenoid labrum. Magnetic resonance imaging appearance of the labrum may assist the clinician in distinguishing the varying forms of shoulder dysfunction and facilitate diagnosis and effective treatment.     

Direct MR arthrography of the shoulder: is exercise prior to imaging beneficial or detrimental?

PURPOSE: To define the beneficial and detrimental effects of adding exercise to direct magnetic resonance (MR) shoulder arthrography. MATERIALS AND METHODS: Direct, intraarticular, gadolinium arthrography of the shoulder was performed in 41 patients, who underwent 1.5-T MR imaging before and after 1 minute of arm swinging. Fourteen milliliters of dilute gadolinium solution was injected. Two readers blinded to exercise independently graded the randomly distributed images with a five-point scale for capsular contrast material resorption; extraarticular contrast material leakage; rotator cuff, glenoid labrum, and anterior capsule conspicuity; and partial-thickness or full-thickness rotator cuff tear and labral tear detectability. The sign test was performed to evaluate the significance of differences between preexercise and postexercise grading for each reader. A second review was performed, with direct side-by-side comparison of preexercise and postexercise images. RESULTS: There was evidence of increased capsular resorption after exercise but no alteration in the depiction of the rotator cuff tendons or glenoid labrum. There was no significant extraarticular contrast material leakage after exercise and no alteration in depiction of the anterior capsule. There was no difference in the detectability of rotator cuff or labral tears. CONCLUSION: Exercise with direct shoulder MR arthrography has no beneficial or detrimental effect on image quality or on the depiction of rotator cuff or labral tears.     

Athlete shoulder injuries: CT arthrographic findings

Forty-three professional and amateur athletes with persistent shoulder pain that interfered with their sports activities were evaluated by computed tomographic (CT) arthrography. In 19 patients, glenohumeral instability (14 anterior, two posterior, three multidirectional) was diagnosed with CT arthrography based on the simultaneous presence of labral and capsular lesions. The findings were crucial in establishing the diagnosis of instability in six patients in whom the condition was not suggested or could not be confirmed clinically. Another significant injury consisted of labral lesions not associated with glenohumeral instability. These tears often involved the anterior and parasuperior segments of this structure. Other, less frequently detected lesions included segmental labral enlargement and several labra with abnormal orientation (everted labrum). Early onset of degenerative disease was present in many athletes, especially those with a long history of sports activity. CT arthrographic findings were correlated with arthroscopic or surgical results in 19 patients.     

SLAP lesions: anatomy, clinical presentation, MR imaging diagnosis and characterization

Superior labral anterior posterior (SLAP) tears are an abnormality of the superior labrum usually centered on the attachment of the long head of the biceps tendon. Tears are commonly caused by repetitive overhead motion or fall on an outstretched arm. SLAP lesions can lead to shoulder pain and instability. Clinical diagnosis is difficult thus imaging plays a key diagnostic role. The normal anatomic variability of the capsulolabral complex can make SLAP lesions a diagnostic challenge. Concurrent shoulder injuries are often present including rotator cuff tears, cystic changes or marrow edema in the humeral head, capsular laxity, Hill-Sachs or Bankart lesion. The relevant anatomy, capsulolabral anatomic variants, primary and secondary findings of SLAP tears including MR arthrography findings, types of SLAP lesions and a practical approach to labral lesions are reviewed.     

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 instability: impact of glenohumeral arthrotomography on treatment

We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.