Shoulder impingement syndrome: MR findings in 53 shoulders

The shoulder impingement syndrome refers to a condition in which the supraspinatus tendon and subacromial bursa are chronically entrapped between the humeral head inferiorly and either the anterior acromion itself, spurs of the anterior acromion or acromioclavicular joint, or the coracoacromial ligament superiorly. As a result, the space for the bursa and tendon is reduced, and repeated trauma to these structures leads to bursitis and rotator cuff injury. Although pain and limitation of motion are common early findings, the diagnosis is often delayed until a complete tear of the rotator cuff has occurred. In an attempt to determine if MR can be used to depict the abnormalities associated with impingement syndrome (subacromial bursitis, supraspinatus tendinitis, and rotator cuff tear), we reviewed 107 MR scans of painful shoulders. Changes consistent with impingement syndrome were found in 53 patients (50%), 32 of whom underwent subsequent arthrography or surgery. MR was found capable of depicting several soft-tissue and bony abnormalities that have been clinically described in impingement syndrome. In regions of inflammation, we found that the supraspinatus tendon and/or the subacromial bursa were compressed by spurs (25 shoulders), capsular hypertrophy of the acromioclavicular joint (six shoulders), and/or low-lying acromion (14 shoulders). While T1-weighted MR imaging was highly sensitive to abnormalities of the supraspinatus tendon, tendinitis could be differentiated from a small tear of the supraspinatus tendon only with T2-weighted imaging. Large, full-thickness tears, especially if chronic, produced characteristic MR findings on both T1- and T2-weighted images. We conclude that MR can be used to detect several abnormalities associated with the shoulder impingement syndrome.     

Shoulder impingement: objective 3D shape analysis of acromial morphologic features

PURPOSE: To retrospectively and quantitatively analyze the acromial undersurface in three dimensions and to determine its association with impingement syndrome and rotator cuff tears. MATERIALS AND METHODS: Institutional review board approval was received with exemption of informed consent for this retrospective HIPAA-compliant study. Magnetic resonance images were evaluated in 84 patients (63 males, 21 females; mean age, 42.6 years; age range, 15-74 years). On the basis of surgical results, patients were separated into three groups: those without shoulder impingement or rotator cuff tears (31 patients), those with shoulder impingement (22 patients), and those with rotator cuff tears (31 patients). To quantitate the acromial undersurface, the structure was manually plotted, and a mathematic model was created by using splines. The undersurface was divided into a 20 x 20 grid. For each patient, a shape index (SI) data set and local undersurface angulation (LUA) data set were determined. Regression analyses were used to identify differences between groups, and prediction models were constructed on the basis of correspondent areas. RESULTS: Analysis of both data sets yielded no apparent progression between groups and demonstrated a lack of similarity between the impingement and rotator cuff tear groups. Discrimination between groups could be demonstrated by dividing the lateral portion of the acromial undersurface into contiguous blocks. The highest overall diagnostic accuracy of our prediction models was 58.3% (49 of 84) by using 10 blocks of the SI data set and 73.8% (62 of 84) by using five blocks of the LUA data set. Conclusion: Three-dimensional modeling yields objective data about the acromial undersurface. On the basis of this method, osseous impingement by the acromion is not a primary cause of shoulder impingement syndrome or rotator cuff tears.     

Coracoid tip position on frontal radiographs of the shoulder: a predictor of common shoulder pathologies?

The coracoacromial arch is a static anterior-superior stabilizer of the humeral head. Thus coracoacromial arch inclination, which varies depending on coracoid tip position, may be related to shoulder pathologies. Therefore, we retrospectively analysed coracoid tip positions in the true anterior posterior view of different shoulder pathologies: reference shoulders (n=27), shoulders with rotator cuff tear (supraspinatus tear n=29; subscapularis tear n=21) and shoulders with anterior glenohumeral instability (traumatic n=17; atraumatic n=14). In supraspinatus tear shoulders, the coracoid tip projected onto inferior glenoid half in 86% of cases (type I coracoid), extending more inferiorly compared with reference group (p=0.0002) or subscapularis tear shoulders (p<0.0001). In contrast, 78% of cases with subscapularis tear show the coracoid tip projected onto the superior glenoid half (type II coracoid). Atraumatic glenohumeral instabilities had a more superior coracoid tip position than traumatic instabilities (p=0.04), but no differences were observed on basis of coracoid type or in comparison with normal controls. We conclude that coracoid tip position is highly variable. Since type I coracoids are predominant in shoulders with supraspinatus tears and type II coracoids in shoulders with subscapularis tears, coracoid tip position may thus provide a simple diagnostic complement for a probable site of rotator cuff tears.     

The relationship of acromial architecture to rotator cuff disease

Variations in the architecture of the coracoacromial arch can lead to a clinically symptomatic rotator cuff lesion. Differences in the development and morphology of the acromion, and the presence of anterior acromial spurs and inferior acromioclavicular osteophytes decrease the volume of the subacromial space, leading to impingement. Recent anatomic, radiographic, biomechanical, and SPG studies have confirmed these architectural variations and their effects on the contents of the subacromial space. Abnormal contact between the acromion and these soft tissues can lead to pathologic lesions. Surgical procedures should be directed at increasing the space beneath the coracoacromial arch to reduce wear on the rotator cuff.     

Is coracoacromial arch angle a predisposing factor for rotator cuff tears?

PURPOSE

The aim of the present study was to investigate whether coracoacromial arch angle is a predisposing factor for rotator cuff tears.

METHODS

Shoulder magnetic resonance imaging (MRI) examinations of 40 patients having shoulder arthroscopy due to rotator cuff tears and 28 patients with normal MRI findings were evaluated retrospectively. Acromio-humeral distance, coraco-humeral distance, the angle between the longitudinal axis of the coracoacromial ligament and longitudinal axis of the acromion (coracoacromial arch angle), and thickness of the coracoacromial ligament were measured.

RESULTS

In patients with rotator cuff pathology the mean coraco-humeral distance was 7.88±2.37 mm, the mean acromio-humeral distance was 7.89±2.09 mm, and the mean coracoacromial arch angle was 132.38°±6.52° compared to 11.67±1.86 mm, 11.15±1.84 mm, and 116.95°±7.66° in the control group, respectively (P < 0.001, for all). In regression analysis, all three parameters were found to be significant predictors of rotator cuff tears. The mean thickness of the coracoacromial ligament was not significantly different between the patient and control groups (0.95±0.30 mm vs. 1.00±0.33 mm, P > 0.05).

CONCLUSION

Acromio-humeral and coraco-humeral distances are narrower than normal limits in patients with rotator cuff tears. In addition, coracoacromial arch angle may be a predisposing factor for rotator cuff tears.The most common cause of shoulder pain is rotator cuff pathology, especially in advanced age. Repetitive overhead arm activities, advanced age, morphology of the glenohumeral joint, acromion type, and soft tissue pathologies surrounding the joint have been introduced among its etiologies (1, 2). Neer and et al. (3) defined impingement as a cause of rotator cuff tear in 1972. They also showed that other than shape of the acromion, the coracoacromial ligament and acromioclavicular ligament were associated with tears (3). In later studies it was determined that shoulders with rotator cuff tear had smaller supraspinatus outlet area (4). Burns and Whipple (5) found that the coracoacromial ligament was more effective on impingement than acromion type. Therefore, coracoacromial arch geometry has gained importance and numerous studies, mostly on cadavers, have been performed.The aim of the present study was to investigate whether the coracoacromial arch angle is a predisposing factor for rotator cuff injury.     

Deltoid muscle and tendon tears in patients with chronic rotator cuff tears

Purpose To describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery. Materials and methods Deltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues. Results There were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients. Conclusion Tears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear.     

Schulterimpingement

The impingement syndrome is a clinical entity characterized by shoulder pain due to primary or secondary mechanical irritation of the rotator cuff. The primary factors for the development of impingement are a curved or hook-shaped anterior acromion as well as subacromial osteophytes, which may lead to tearing of the supraspinatus tendon. Secondary impingement is mainly caused by calcific tendinopathy, glenohumeral instability, os acromiale and degenerative changes of the acromioclavicular joint. Conventional radiographs are initially obtained, mainly for evaluation of the bony structures of the shoulder. If available, sonography can be used for detection of lesions and tears of the rotator cuff. Finally, MR-imaging provides detailed information about the relationship of the acromion and the acromioclavicular joint to the rotator cuff itself. In many cases however, no morphologic cause for impingement syndrome can be found. While patients are initially treated conservatively, chronic disease usually requires surgical intervention.     

The prevention and treatment of injuries to the shoulder in swimming

The biomechanics of swimming cause considerable stress on the shoulder joint which may be accentuated by improper stretching or training techniques. The rotator cuff, and particularly the supraspinatus tendon, is at risk in repetitive overhead stroke activity. Arthritis in the shoulder is primarily centered at the acromioclavicular joint; degeneration may occur as a result of overuse or leverage of the scapuloclavicular mechanism, or from motion related to upward pressure at the undersurface of the acromion due to subluxation or instability of the glenohumeral joint. Instability of the glenohumeral joint is a major problem which may occur in itself or in combination with rotator cuff tendinitis. The glenohumeral joint is stabilised superiorly by a posterior superior sling consisting of the long biceps tendon, the superior joint capsule, and the coracoacromial and coracohumeral ligaments. An anterior inferior sling mechanism consisting of the inferior glenohumeral ligament and subscapularis musculotendinous unit provides significant stability if uninjured. Fragments of labral tissue may mechanically wedge into the joint also leading to symptoms of subluxation. If the humeral head is wedged or allowed to slip out of joint due to capsular incompetency, secondary rotator cuff 'impingement' may occur; this is particularly difficult to manage. Prevention of injury is best accomplished through a programme of flexibility and strengthening avoiding overuse.     

Differences in acromial morphology of shoulders in patients with degenerative and traumatic supraspinatus tendon tears

Purpose

Distinct characteristics of acromial morphology seem to be one factor for the development of degenerative supraspinatus tendon tears. Thus, it is questionable whether patients with traumatic tendon tears also present these parameters. The hypothesis of the present study was that the acromial morphology of patients with degenerative supraspinatus tendon tears differs from patients with traumatic tears.

Methods

One hundred and thirty-six patients that were treated by arthroscopic rotator cuff repair from 2010 to 2013 were included in this study. Seventy-two patients had degenerative (group 1), and 64 had traumatic (group 2) supraspinatus tendon tears. On preoperative radiographs the Bigliani type, acromial slope, acromiohumeral (AH) distance, lateral acromial angle (LAA), acromion index (AI), and critical shoulder angle (CSA) were measured. Medians of these parameters as well as of age of both groups were compared using the t test.

Results

The percentaged distribution of the Bigliani type differed (group 1 vs. 2: type 1: 18/38, type 2: 56/55, type 3: 26/8). All parameters showed significant differences between degenerative and traumatic tears. Slope: 21.2° (SD 7.6°) versus 19.2° (SD 7.9°, p = 0.026), AH distance: 8.4 mm (SD 2.3 mm) versus 9.9 mm (SD 1.9 mm, p = 0.0006), LAA: 77.0° (SD 4.0°) versus 82.5° (SD 4.7°, p < 0.0001), AI: 0.77 (SD 0.07) versus 0.73 (0.06, p = 0.0239), and CSA: 36.8° (SD 3.6°) versus 35.3° (SD 2.9°, p = 0.007). An LAA <70° or an AH distance of <5 mm only occurred in degenerative tears. Patients with degenerative tears were significantly older (60 vs. 54 years).

Conclusions

The hypothesis that the acromial morphology of patients with degenerative supraspinatus tendon tears differs from patients with traumatic tears was confirmed. Shoulders with degenerative tears show a narrower subacromial space and a larger lateral extension as well as a steeper angulation of the acromion than with traumatic tears. Thus, the results of this study support the theory of external impingement as a cause for degenerative rotator cuff tears.

Level of evidence

IV.

     

Measurement of subacromial impingement of the rotator cuff

Objective: Recent evidence suggests that shoulder impingement syndrome arises from primary rotator cuff pathology and may be related to the inability of the rotator cuff to prevent superior humeral head migration in shoulder elevation. Impingement involves compression of subacromial structures, including the rotator cuff. Previously, clinical tests have been shown to be inaccurate in diagnosing rotator cuff impingement. A lack of anatomical validity might explain the inaccuracy of these tests. This study aimed to clarify the anatomical basis of subacromial compression of the rotator cuff by analysing the compression forces generated and observing the structures impinged in a variety of shoulder positions. Design: This observational case series involved the dissection of nine embalmed cadaveric shoulders. Method: Pressure transducers were placed deep to the coracoid process, coracoacromial ligament, the anterior acromion and the posterior acromion. Shoulders were moved into internal and external rotation from the positions of flexion, abduction and extension. At each position, pressure readings were recorded and structures being compressed observed visually. Results: Highest pressures were recorded in flexion/internal rotation at the coracoacromial ligament, in abduction/internal rotation at the coracoid process (both involving the rotator interval) and in abduction/internal rotation at the coracoacromial ligament (involving supraspinatus). Supraspinatus was also observed to be compressed in extension/external rotation (against the anterior acromion). Infraspinatus was compressed in extension/external rotation (against the posterior acromion), while subscapularis was compressed in flexion/internal rotation and flexion/external rotation (both against the coracoid process). Conclusion: This study identifies shoulder positions likely to impinge particular rotator cuff tendons.     

The scapuloacromial angle: a 3D analysis of acromial slope and its relationship with shoulder impingement

PURPOSE: To quantify acromial slope (the scapuloacromial [SA] angle). MATERIALS AND METHODS: We used shoulder MR studies in 64 subjects who were stratified surgically into impingement (with and without tear) and nonimpingement (shoulder instability) groups. We measure, in three dimensions, the angle between unit normal vectors to planes of best fit to the undersurface of the acromion and the medial surface of the blade of the scapula. We examine the projection of this SA angle onto the transverse, coronal, and sagittal planes to gauge some measure of rotation, lateral tilt, and anterior tilt with respect to the patient. Orientation of the acromion and scapular blade in relation to the MR scanner and therefore to the patient was also calculated. RESULTS: We found no significant differences between these two groups when examining age and side of pathology. A statistically significant difference was seen between males and females. CONCLUSION: Our study does not support the idea that a flatter acromial slope causes impingement and is an etiological basis for rotator cuff tears. We believe that acromial slope, regardless of imaging plane, is not useful in classifying patients who present with shoulder pain and should not be considered as a source of pathologic changes.     

Rotator cuff tears: assessment with MR arthrography in 275 patients with arthroscopic correlation

We assessed the diagnostic performance of magnetic resonance (MR) arthrography in the diagnosis of articular-sided partial-thickness and full-thickness rotator cuff tears in a large symptomatic population. MR arthrograms obtained in 275 patients including a study group of 139 patients with rotator cuff tears proved by arthroscopy and a control group of 136 patients with arthroscopically intact rotator cuff tendons were reviewed in random order. MR imaging was performed on a 1.0 T system (Magnetom Expert, Siemens). MR arthrograms were analyzed by two radiologists in consensus for articular-sided partial-thickness and full-thickness tears of the supraspinatus, infraspinatus, and subscapularis tendons. At arthroscopy, 197 rotator cuff tears were diagnosed, including 105 partial-thickness (93 supraspinatus, nine infraspinatus, three subscapularis) and 92 full-thickness (43 supraspinatus, 20 infraspinatus, 29 subscapularis) tendon tears. For full-thickness tears, sensitivity, specificity, and accuracy were 96%, 99%, and 98%, respectively, and for partial tears 80%, 97%, and 95%, respectively. False negative and positive assessments in the diagnosis of articular-sided partial-thickness tears were predominantly [78% (35/45)] observed with small articular-sided (Ellman grade1) tendon tears. MR arthrography is highly accurate in the diagnosis of full-thickness rotator cuff tears and is accurate in the diagnosis of articular-sided partial-thickness tears. Limitations in the diagnosis of partial-thickness tears are mainly restricted to small articular-sided tears (Ellman grade 1) due to difficulties in differentiation between fiber tearing, tendinitis, synovitic changes, and superficial fraying at tendon margins.     

The importance of imaging technics in the diagnosis of sports related periarticular shoulder lesions

Numerous kinds of sports lead to lesions of the periarticular tissue of the shoulder, which can result in the supraspinatus syndrome or incomplete and complete rupture of the rotator cuff. Standard radiography is of limited use in the diagnosis of periarticular diseases of the shoulder. Osseous alterations in the greater tubercle and undersurface of the acromion can be explained as a supraspinatus syndrome or a long-standing rupture of the rotator cuff in connection with high positioning of the head of the humerus. A rupture of the rotator cuff is demonstrated by arthrography of the shoulder joint, a diagnostic method that we think is necessary despite regular examinations with ultrasonography.     

Rotator cuff tears: association with acromion angulation on MRI

ObjectiveUsing magnetic resonance imaging (MRI), evaluate the correlation of acromion angulation with thickening of the coracoacromial ligament (CAL) and narrowing of the subacromial space resulting in impingement upon the rotator cuff tendons.Materials and methodsEighty-nine shoulder MRI studies performed on a 3T scanner were retrospectively analyzed by two blinded independent reviewers. Measurements of the acromion angle (delta angle), CAL thickness and distance between the CAL and humeral head were obtained. The data were categorized into two groups, delta angle less that and greater than 7.5°. The presence or absence of full thickness (FT) or near full thickness (NFT) rotator cuff tears was noted.ResultsIn group 1, the acromion angle varied from -6.8 to 6.8° (1.7±3.5°) with a CAL thickness of 0.91±0.20 mm and a subacromial distance of 6.47±0.88 mm. Group 2 acromion angle varied from 7.6° to 46.8° (18.0°±8.1°) with a CAL of 1.77±0.51 mm and a subacromial distance of 4.52±0.82 mm. The difference in CAL thickness and subacromial distance were significantly different between the two groups (P<.001). In Group 1, 3 out of 51 patients had a FT or NFT tear of the rotator cuff compared to 20 out of 38 in Group 2 (P<.001). There was no significant interobserver variability.ConclusionSteep acromion angulation is associated with CAL thickening and narrowing of the subacromial space. Patients with a steep acromion angle had a statistically increased incidence of rotator cuff tears.     

The rotator cuff functional index

BACKGROUND: Despite improvements in the clinical assessment of rotator cuff injuries, shortcomings exist in diagnosing rotator cuff tears. PURPOSE: To formulate a clinical rotator cuff functional index for predicting rotator cuff tears based on handheld dynamometer measurements for shoulder strength testing and to assess its ability to diagnose a rotator cuff tear. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Preoperative handheld dynamometer measurements, including supraspinatus, external rotation, internal rotation, adduction, and lift-off force, were compared in 100 patients with full-thickness rotator cuff tears (> 1.0 cm) and 100 patients with no rotator cuff injury (confirmed by arthroscopy). Using multiple logistic regression analysis, the rotator cuff functional index and index for rotator cuff tear size were formulated in which 100 represented excellent rotator cuff function and less than 0 indicated a full-thickness supraspinatus tear. Each patient's index was calculated to determine its clinical value in predicting a rotator cuff tear; the Pearson correlation coefficient was established for the rotator cuff functional index for rotator cuff size. RESULTS: Two handheld dynamometer measurements predicted a rotator cuff tear (P < .001, r = 0.53), with rotator cuff functional index = 1.27 * supraspinatus (N) - 0.72 * adduction (N) - 11.6, but not tear size (r = 0.38). In predicting a rotator cuff tear (rotator cuff functional index < 0 = rotator cuff tear; rotator cuff functional index > 0 = no tear), the rotator cuff functional index had 83% sensitivity, 79% specificity, 80% positive predictive value, 82% negative predictive value, likelihood ratio of 4.0 for a positive test result and 0.2 for a negative test result and an accuracy of 81%. CONCLUSION: The 2 most useful tests for determining a rotator cuff tear with a handheld dynamometer were supraspinatus force and adduction force (as negative control). A functional index based on these measurements was able to rule out a rotator cuff tear and predict the presence but not the size of the tear.     

Distal clavicular osteolysis: MR evidence for subchondral fracture

Purpose To investigate the association between distal clavicular osteolysis and subchondral fractures of the distal clavicle at MRI. Materials and methods This study was approved by the hospital human research committee, which waived the need for informed consent. Three radiologists retrospectively analyzed 36 shoulder MR examinations in 36 patients with imaging findings of distal clavicular osteolysis. The presence of a subchondral fracture of the distal clavicle, abnormalities of the acromioclavicular joint, rotator cuff tears and labral tears were assessed by MRI. These cases were then compared with 36 age-matched controls. Results At MRI, 31 of 36 patients (86%) had a subchondral line within the distal clavicular edema, consistent with a subchondral fracture. Of the 36 patients, 32 (89%) had fluid in the acromioclavicular joint, while 27 of 36 patients (75%) had cysts or erosions in the distal clavicle. There were 13 patients (36%) with associated labral tears, while eight patients (22%) had partial-thickness rotator cuff tears. In the control group one of 36 (3%) had a subchondral line (P<0.05), while ten of 36 (28%) had rotator cuff tears and 13 of 36 (36%) had labral tears. These latter two were not statistically significant between the groups. Conclusion A distal clavicular subchondral fracture is a common finding in patients with imaging evidence of distal clavicular osteolysis. These subchondral fractures may be responsible for the propensity of findings occurring on the clavicular side of the acromioclavicular joint.     

Sonography of the painful shoulder: role of the operator’s experience

Objective  The aim of our study was to determine the role of the operator’s experience in the sonographic evaluation of the painful shoulder and to validate assumptions about its technical performance in routine practice. Materials and methods  Two radiologists, respectively standard and expert sonographic operators, independently and prospectively scanned 65 patients with clinical suspicion of rotator cuff lesion. Magnetic resonance arthrography was the reference standard. Results  The sensitivity of the expert ultrasound operator was 95.3% for full-thickness rotator cuff tears (41/43), 70.6% for partial-thickness tears (12/17), 64.3% for intratendinous tears (9/14), 100% for abnormality of the long head of biceps tendon (seven of seven), 88.9% for supraspinatus tendinosis (16/18), 96.4% for subacromial bursa abnormalities (53/55), and 91.7% for acromioclavicular joint osteoarthritis (33/36). The two sonographic operators were in very good agreement about full-thickness rotator cuff tears (κ = 0.90), supraspinatus tendinosis (κ = 0.80), abnormalities of the long head of biceps tendon (κ = 0.84), subacromial bursa abnormalities (κ = 0.89), and acromioclavicular osteoarthritis (κ = 0.81). The agreement was only moderate for partial-thickness tears (κ = 0.63) and intratendinous tears (κ = 0.57). Conclusions  Our results show that in moderately experienced hands as in experts’ hands, sonography has a low level of interobserver variability for full-thickness rotator cuff tears. Considering partial-thickness and intratendinous rotator cuff tears, our data suggest that interobserver variability is higher.     

MR evaluation of subscapularis tears.

PURPOSE: The purpose of this work was to describe the MR appearance of tears of the subscapularis tendon and compare the usefulness of different imaging planes as well as note the association of subscapularis tears with other rotator cuff tears and biceps tendon dislocations. METHOD: MR studies at 1.5 T over an 8 year interval were retrospectively assessed for the presence of a rotator cuff tear and/or tear of the subscapularis tendon. Images that showed a subscapularis tear were reviewed for the presence of a visible tear separately on the axial, coronal, and sagittal images. The MR studies were also evaluated for associated tears of the supraspinatus, infraspinatus, and teres minor muscles as well as biceps tendon dislocation and the "naked humerus sign" on coronal images. Last, clinical records and surgical reports were reviewed. RESULTS: Forty-five (2%) of 2,167 rotator cuff tears involved the subscapularis; 27% were partial and 73% were complete tears. Tears were best seen in the sagittal oblique plane. Almost all subscapularis tears were an extension of typical rotator cuff tears: supraspinatus in 35 patients (79%), extending into infraspinatus tears in 25 (56%) and into teres minor tears in 2 patients (4%). Bicipital dislocations were seen in 22 patients (49%), and three complete tears of the biceps (7%) were noted as well. The naked humerus sign was demonstrated in 31 patients (69%). Surgical reports that confirmed the MR findings were available for 15 patients. CONCLUSION: About 2% of rotator cuff tears involve the subscapularis tendon. Most subscapularis tears are extensions of supraspinatus tears and frequently involve the biceps tendon.     

Supraspinatus outlet view in the diagnosis of stages II and III impingement syndrome

Purpose: To compare supraspinatus outlet view (SOV) findings at different stages of the impingement syndrome (IS) with findings in asymptomatic age- and sex-matched controls.Material and Methods: Pre-operative SOVs were obtained of 37 shoulders of patients scheduled for unilateral open repair of a full-thickness rotator cuff tear (stage III IS) and 74 shoulders of patients scheduled for open (n=46) or arthroscopic (n=28) acromioplasty for tendinitis (stage II IS). Each view of a patient's shoulder was paired with a control view obtained from an age- and sex-matched person with no shoulder problems (n=111).Results: There were no significant differences in acromial morphology as evaluated on the scale devised by Bigliani et al. or in the tilt, slope or length of the acromion between the study groups and their controls. However, hooked acromion seemed to be more common in the patients. The thickness of the anterior part of the acromion at the tendinitis stage and the acromial angle at the tear stage of IS were the only parameters that showed significant differences between patients and controls.Conclusion: Variation of the morphology of the acromion as evaluated on a basis of the SOV is associated with IS, but the association is weak and its value in the diagnosis of IS is therefore only as an adjunctive to other diagnostic modalities.     

The shoulder impingement syndrome: prevalence of radiographic findings and correlation with response to therapy

The shoulder impingement syndrome is believed to be caused by compression of the rotator cuff tendons and subacromial bursa between the humeral head and structures that make up the coracoacromial arch. Plain film findings were tabulated for 36 patients, 22-81 years old, who had signs and symptoms of an acute impingement syndrome. The most common radiographic abnormalities were subacromial bony proliferation in 68%, degenerative changes in the greater tuberosity of the humerus in 66%, and degenerative joint disease in the acromioclavicular joint in 66%. There was evidence of calcium deposition in the rotator cuff in 37%, inferiorly oriented acromioclavicular osteophytes in 32%, and degenerative changes of the lesser humeral tuberosity in 29%. The acromiohumeral space was narrowed in only 21%. The radiographic findings were scored blindly and compared to the treatment outcome of 6 weeks of medical therapy. There was no statistically significant correlation between any of the radiographic findings and the response to medical therapy. The results suggest that radiographic findings are extremely common in patients with the acute impingement syndrome, but that they are not useful as prognostic indicators of the short-term response to medical treatment.