Abstracts

Session 1
Introduction (1) : Imaging of the Upper Extremity – Routine and New Techniques

Moderators : F. Burny, J.D. Laredo

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Opening Address

F. Schuind
Department of Orthopedics and Traumatology, Cliniques Universitaires de Bruxelles, Hôpital Erasme, Brussels, Belgium

Since Roentgen’s discovery of x-rays in 1895 and the first radiograph, of a hand, techniques for imaging the skeleton have changed dramatically. If, more than one hundred years later, high-quality conventional radiographs are still essential, many other techniques are now available in most institutions, including conventional or computed tomography, arthrography, ligamentography, tenography, CT-arthrography, magnetic resonance imaging, angiography, ultrasound, static and dynamic scintigraphy, and diagnostic arthroscopy. New techniques are under development. Electronic distribution of digitalized images raises ethical, legal and organization problems. Parallel to this explosion of imaging modalities, there has been remarkable progress in the knowledge of normal upper extremity anatomy, normal variants and of various diseases, whether of traumatic, degenerative, inflammatory or of tumoral origins. In particular, the ligamentous instabilities affecting the joints of the upper extremity have become extremely complicated. The best diagnostic approach to a particular clinical situation, choosing the most adequate and economical techniques of imaging, has therefore become a challenge. In many clinical situations, subtle interpretation of good-quality conventional x-rays provides all the essential information. There is no consensus regarding the indications for some other techniques, including ultrasound and magnetic resonance imaging. On the other hand, the clinician is frequently faced nowadays with many images acquired from a particular patient, experiencing difficulties with interpretation and hesitation as to the best therapeutic approach. The images have become so precise that tiny degenerative or traumatic processes are perfectly evident, yet do not always explain the symptoms experienced by the patient. In addition, the clinician frequently has other requests to address to the imaging specialists, including imaging for preoperative planning and quantitative morphometry techniques for the objective evaluation of results of various treatment modalities. The primary goals of this symposium, gathering together in a first-class resort close to Brussels anatomists, radiologists/imagers, nuclear medicine scientists, orthopedic surgeons, hand surgeons, plastic surgeons and physiotherapists, are therefore to reach a consensus as to the imaging of the shoulder, elbow and wrist in their various pathologies. As a symbol of the indespensable close cooperation between image and clinic, the symposium has received the patronage of the GETROA (Groupe d’Étude et de Travail en Ostéo-Articulaire).

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The GETROA

J.J. Railhac1, J.D. Laredo2
1 Hôpital Purpan, Toulouse, France
2 Department of Radiology, Hôpital Lariboisière, Paris, France

Abstract not received in time

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The Better the History and Physical, the Better the Imaging !

James H. Dobyns
The Hand Center, San Antonio, USA

Introduction - Historically, radiologists never tired of asking validation for the study requests made to them. Such requests availed them little to the point that desperation led many of them to do auxiliary histories and physicals of their own. Whatever the source of a diligent history and a focused examination, the improved yield in relevant imaging studies is worthwhile. The attrition of time, the increased number of imaging techniques, including invasive techniques, the use of imaging techniques by non-radiologists have made early cut-to-the-core decisions even more important.

Classification of 'Triad' (Hx., Px., Ix.) - Errors:

  1. Incomplete History, Incomplete Examination → Imaging diagnostic, irrelevant or incomplete;
  2. Accurate History, Incomplete Examination → Imaging diagnostic, irrelevant, incomplete;
  3. Incomplete History, Accurate Examination → Imaging diagnostic, irrelevant, incomplete;
  4. Accurate History, Accurate Examination → Imaging diagnostic, irrelevant, incomplete.

Examples of 'Triad' Interaction :

  1. History of vague wrist pain of indeterminate nature, age and causation. Examination records diminished grip and normal range of motion. Standard imaging reveals Kienböck’s disease.
  2. History of gradual onset of wrist pain in young female gymnast with no localizing findings recorded and no definite imaging abnormalities on standard radiographs. Re-examination found tenderness at ulnar distal radius, distal radio-ulnar joint and ulnocarpal area. Comparison radiographs of the opposite wrist revealed thinning of the ulnar half of the distal radius physis on the involved side, a slight ulna plus on the involved side vs. an ulna minus on the uninvolved side and a bone scan revealed vascular hyperactivity in the same areas noted to be tender. A diagnosis of gymnast’s wrist inclusive of physis damage to the distal radius was confirmed.
  3. Indeterminate history of intermittent wrist pain of uncertain onset. Examination revealed tenderness at the scapholunate area, prominence of proximal scaphoid, particularly on radial deviation or flexion, a billotable scaphoid and a positive scaphoid subluxation click. Standard imaging was equivocal but a grip PA in supination confirmed a diagnosis of scapholunate dissociation.
  4. History of a torque-compression injury to the wrist from steering wheel forces combined with a finding of pain, tenderness and subluxation of the ECU tendon during muscle contraction and active deviation led to an appropriate diagnosis of acute ECU tendon sheath tear. Standard x-rays were normal. After the sheath repair ECU subluxation and pain stopped but ulnar wrist pain continued and patient complained of a `jumping wrist’. Videofluoroscopy of wrist motion included provocative maneuvers and an arthrogram, which revealed a VISI shift during wrist circumduction as the wrist moved from flexion and radial deviation to extension and ulnar deviation. There was arthrographic evidence of dye leakage between the lunate and the triquetrum. A diagnosis of lunotriquetral dissociation with CID-VISI instability was confirmed.

Conclusion - The importance of relevant in-depth history taking and experienced, knowledgeable physical examination is so important in selecting confirmatory tests, often imaging studies, that ideally the two physicians most involved, i.e. the clinician and the radiologist should review both aspects of information gathering and, if indicated, reach a consensus with re-selection of the appropriate imaging study(s)!

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Concepts in Shoulder Cuff Imaging

B. Vande Berg, J. Malghem, F. Lecouvet
Department of Radiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium

The current presentation will describe the various techniques that are available to investigate rotator cuff diseases. Specific patterns of tendinous lesions will be introduced, and their variable appearances depending on the technique used will be shown. The benefits and limitations that are intrinsic to each technique will be reported with emphasis on the areas that cannot be visualized.

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Diagnostic Imaging of the Shoulder, Elbow and Wrist Joints
"Questions about routine plain films of the shoulder, elbow and wrist"

S. Sintzoff Sr
Consultation d'Imagerie Médicale, Brussels, Belgium

Any evaluation of upper extremity joint disease through imaging should begin with routine radiography. In 2000, for most upper limb diseases, conventional radiography remains the best and certainly the cheapest way of accurately detecting a problem. If high quality radiographs are obtained in properly positioned patients, a diagnosis, be it direct or indirect (exclusion), cannot be made without routine plain films.

Shoulder - Shoulder pain is second only to neck and low back pain as a musculoskeletal complaint encountered by physicians. Disorders leading to those symptoms are numerous and often relate to the unique anatomic relationship present about the glenohumeral joint.

Despite all of the published studies and numerous lectures and discussion panels there still is no consensus on how best to image the shoulder. Even if one considers identical clinical problems, radiologists and orthopedic surgeons have many different opinions concerning the best imaging approach. There is still no agreement on how these various imaging options (plain films, scintigraphy, US, CT and MRI) should be applied to shoulder pain evaluation when the clinical situation, efficacy of the imaging method, costs, and relative risks are considered. After reviewing the literature and listening to the clinical experience of different radiologists, I believe that a review of shoulder imaging should be subtitled "state of confusion" rather than "state of the art." The question is, can the imaging technique itself provide new unique information that changes the diagnostic and therapeutic approach to joint diseases. More important, what provides the necessary answers to the key clinical questions with reasonable accuracy and costs?.

Although this has not appeared in the literature, one can find clinicians, particularly orthopedists, who believe that diagnostic shoulder imaging is in disarray and have all but abandoned any imaging studies other than radiography, preferring to rely on history and physical examination alone and resorting to diagnostic arthroscopy in problem cases.

Shoulder routine radiography - Most recent clinical and radiologic developments in the evaluation and diagnosis of shoulder dysfunction have been driven by two pathophysiologic concepts: (1) impingement syndrome and rotator cuff disease and (2) glenohumeral instability, labral and ligament abnormality. Impingement pathophysiology may coexist with or be secondary to primary instability, and conversely instability may be secondary to subacromial rotator cuff tendinopathy following (1) an impingement syndrome (this is common in the over-40 age group) and (2) traction overload tendinitis, which is common in the younger more athletic population. In general the problem of instability will manifest earlier in life than impingement syndrome. Therefore if someone presents with impingement symptoms before the age of 35, the physician should consider instability as the primary disorder until proved otherwise. On the other hand, rotator cuff disease secondary to impingement syndrome is more likely to manifest after the age of 40 years. Also, this is not to say that instability is not a problem in patients over 40 years old, and impingement is not a problem in patients younger than 35.

A subacromial/subcoracoid pain syndrome may result from primary impingement rotator cuff tendinitis or degeneration without impingement; shoulder instability with secondary impingement or instability without impingement. It must be remembered that not everyone with shoulder pain and dysfunction has an impingement syndrome, and not everyone with impingement has a primary impingement syndrome.

Routine radiographic examination of the shoulder includes the distal clavicle, the scapula, and the proximal humerus, allowing visualization and interpretation of the glenohumeral joint and, at least in part, of the acromioclavicular joint. This is of practical significance since the sternoclavicular joint and proximal clavicle, though both intimately related to the function of the shoulder, generally are not studied following shoulder trauma unless specifically requested. In addition, complete radiographic evaluation of the scapula requires special views. I shall consider the following clinical situations : impingement, acute rotator cuff tear, traumatic conditions, acute or chronic instability besides frozen shoulder and medical pathology (RA, SPA, hydroxyapatite deposition disease, infections and tumors).

Diagnostic value of routine plain radiography in rotator cuff disease

Radiographic views and technique

A. Static views

Anteroposterior view with double oblique projection - Though highly informative, an AP radiograph of the shoulder with the arm in medial or lateral rotation does not allow adequate visualization of the glenohumeral joint. To view the glenohumeral articulation tangentially, a true AP projection of the shoulder is obtained with a double oblique projection. The first obliquity involves a 45° rotation of the patient towards the side to be studied, releasing the glenohumeral joint line (i.e., posterior oblique position); the second obliquity includes a 25° downward beam, releasing the subacromial space by putting the acromion and the lateral end of the clavicle on the same line. The view is performed with the humerus in three positions. The first is with a neutral rotation with the arm alongside the body, the hand parallel to the thigh, and the thumb pointing forwards. This position reveals the upper aspect of the greater tuberosity, the cortical layer of which is slightly thickened, and the insertion area of the supraspinatus tendon. The quality criterion of the view is an external position of the bicipital groove. The incomplete edge of the lesser tuberosity is superimposed on the lateral, paracentral region of the humeral head. The subacromial space is filled by the anterior part of the supraspinatus tendon and long head of the biceps tendon. The subacromial space is normally 7 to 15 mm wide. An anteroposterior view of the other side is performed in neutral rotation. The second position, in lateral rotation, reveals the anterior surface of the humeral head, protrusion of the lesser tuberosity, and anterior part of the cuff within the subacromial space. The third position, in medial rotation, analyzes the posterior surface of the greater tuberosity, with the insertions of the infraspinatus and teres minor tendons. The lesser tuberosity, seen in profile, stands out on the inferomedial outline of the humeral head. The subacromial space is now filled by the infraspinatus tendon.

True lateral scapular view, true lateral view - The horizontal beam, tangent to the subcutaneous subscapularis region, superimposes the scapular shell on the humeral diaphysis when we remove the contralateral shoulder from the imaging plane. This view is acquired with the patient in a 60° anterior oblique position either upright or recumbent, whichever is more comfortable. The humeral head is centered over a Y-shape formed by the wing of the scapula, scapular spine and coracoid process. This view analyzes the morphology of the acromion and localizes the calcification on the anterior (subscapularis) and posterior (infraspinatus and teres minor) surfaces of the humeral head. Likewise, the projection shows the localization of inferior partial or complete cuff tears on the arthrogram.

Axillary view - The axillary view gives profile information about the glenohumeral joint and transverse axial information about the acromioclavicular joint. The view controls the congruence of the head in the socket and helps us understand the morphology of the lesser tuberosity by unrolling it. The axillary view is best obtained with the patient in a supine position with the arm abducted 90°, but this may be difficult to achieve in cases of severe fractures or dislocations. Satisfactory films can be acquired with only 10° to 15° brachial abduction with the central beam directed at the apex of the axilla. Similar difficulties may be encountered in trying to obtain the West Point view, which traditionally is taken with the patient lying prone with the arm abducted 90° and the hand dangling over the edge of the table. In this position the central beam is angled 25° cephalad and 25° medially. Alternatively, the patient can be evaluated in a sitting position with the arm slightly abducted and the central beam originating from the floor or ceiling. The latter method is much more comfortable for the patient and is feasible in cases of significant shoulder trauma. When the injury precludes evaluation of the shoulder with either an axillary or a West Point view, a true lateral projection of the scapula, or scapular Y-view, may be used.

The acromioclavicular joint - A basic radiographic examination of the acromioclavicular joint should include an AP frontal film of both shoulders with 15° caudal angulation followed, in cases of suspected acromioclavicular joint separation, by an AP frontal radiograph of the affected side with the patient’s arm internally rotated. If no abnormality has been detected up to this point, an AP frontal weight-bearing image of both shoulders with caudal angulation similar to that of the initial film is acquired. It is best accomplished by tying weights of 5 to 15 lb (2.3 to 7 kg) from each wrist.

B. Dynamic Views

Leclercq maneuver, based on AP view in double obliqueness - In his original paper in 1950 about "the diagnosis of the supraspinatus tendon," Leclercq performed, 30 to 45° humeral abduction in external rotation. Such a maneuver results moreover in a physiological subacromial narrowing, owing to the external rotation, so that the greater tuberosity crossing under the acromion does not allow us to evaluate the thickness of the cuff. This "impeded abduction" maneuver was described again in 1965 by Welfing, who also performed humeral abduction of 40 to 45° that made any measurement between the head and acromion inaccurate because of the gliding of the greater tuberosity into the subacromial space. As a matter of fact, the humeral head is fixed in the glenoid cavity in the abduction sector from 0 to 20°. The modified test includes, by intermediate rotation against a resistance or owing to downard traction on the upper limb, opposed abduction of less than 20°, with the superior surface of the greater tuberosity and the cuff in a vertical position above the acromiocoracoid dome. The arm and chest are strapped to prevent abduction. The strap may be replaced by a lateral buttress or by carrying a weight of 4 pounds. The patient then makes an abduction in the coronal (frontal) plane, limited by the strap, the lateral buttress or the weight, in the first 20°.

True AP view in supine position - This technique, proposed by Railhac and Rigal, includes a vertical beam perpendicular to the plane of the table . This view, with the subject supine, releases the recentering action of the weight of the arm on the glenohumeral joint and reveals the upward pull of the humeral head if the upper part of the cuff is ruptured or narrowed.

C. Radiodynamic evaluation of impingement

The reproduction of shoulder pain by Neer’s maneuver (impingement test) is not diagnostic. It can be found at all stages and in other entities. This finding reduces the value of the test and of pain reproduction with or without bone contact.

D. Critical Remarks

Critical study - The axillary view is replaced by the glenoid profile. The transthoracic incidence, which is equivalent to a simple chest profile without raising the examined arm, is dropped in favor of the subacromial profile.

Static view - The AP view, with double oblique projection and neutral, internal and external rotations, releases the subacromial space and glenohumeral joint space, providing a comparative evaluation of the rotator cuff thickness. It visualizes the insertion areas of the cuff tendons and allows the localization of calcifications and tears on arthrography. Neutral and external rotations are useful and essential for visualizing anterosuperior impingement. The internal rotation releases the posterior cuff segment, which is free from the impingement. Its usefulness is limited to the morphological assessment of the lesser tuberosity and calcifications. The true lateral view of the cuff (also called the Y-view, subacromial view, and lateral view of Neer or Lamy) shows the acromiohumeral connections, allows localization of calcifications and on arthrography, shows the extent of partial or total cuff tears. The three-group classification of acromion morphology proposed by Bigliani and Morrisson remains artificial; the authors failed to demonstrate a significant difference in the distribution of the anatomical variants between the normal reference population and the patients with an impingement syndrome without a cuff tear. This classification is discussed in the literature by Haygood, Zukerman and Edelson, acccording to whom it is of no value.

  • Edelson and Taitz looked at osteophyte formation and eburnation involving the acromia of cadaver scapulae and found them to be more prominent on acromia with a horizontal (parallel to the axial plane) slope. No acromions with a slope of 41° or greater above the horizontal (axial plane) had these degenerative changes of the bone. However, 75% of the acromia with slopes of 35° or less had these degenerative changes on the acromial undersurface. The study of a population of 84 cadavers revealed no type III acromia before the age of 30 years.
  • The Williamson study (1994) showed that there was no significant difference in acromial shape between impingement patients and the control population.

The true lateral view of the rotator cuff (or Y-view, Neer’s lateral view, or Lamy’s lateral view) also studies the width of the coracohumeral space compared with the other side. The normal values are discussed in the literature and are not fixed yet. The only practical usefulness is the observation of spatial asymmetry between the two sides.

  • These basic "static" views sometimes reveal the sign of a cuff tear, i.e., collapse of the subacromial space. In a normal stage, this space is filled by the tendons of the upper part of the cuff, especially the supraspinatus tendon, topped by the thin subacromiosubdeltoid bursa. Its thickness varies, according to the authors, from 7 mm to 15 mm with a mean of 10.5 mm. In a retrospective study of 93 shoulders investigated by arthrography, Goupille established that, if the threshold value indicating a cuff tear is fixed at an acromiohumeral width less than or equal to 7 mm, the sensitivity reaches 24% and specifity 75%. According to D. Resnick, no routine radiographic findings are diagnostic of an acute rotator cuff tear that has occurred in the absence of glenohumeral joint dislocation. The fat layer may be filled in acute tears just as in inflammatory processes extending into adjacent tissues, including rheumatoid arthritis and calcifying tendinopathy. Resnick means that we must strictly limit the diagnostic value of what are considered to be indirect signs of chronic cuff tears. Severe degenerative processes or atrophy of the rotator cuff without tears may create changes similar to those seen in chronic tears. He reminds us of the fact that such xray alterations may be present in other entities, especially when they include capsulosis. The signs considered to be indirect and predictive should not be used as a diagnostic tool for chronic rotator cuff tears in either clinical practice or forensics.
  • Osteophytes, acromial and tuberosity sclerosis, type three cystic hooked acromia (Bigliani - Morrisson) are not diagnostic of tendon tears. They correspond to a degenerative senescent involution, chronic tendinosis, whether or not there is decompensation by complete tear.
  • Impingement is not a radiographic diagnosis.  Signs reported to occur in a patient with

impingement did not vary significantly in the control population without clinical signs (Williamson 1994). Narrowing of the subacromial or coracohumeral space may result from chronic tendinosis or tendon atrophy without tear.

  • Impingement - subacromial/subacromioclavicular osteophyte spur. The only plain film finding that proved to be statistically significant for impingement but not for cuff tear is the osteophyte on the undersurface of the acromial/AC joint. Subacromial narrowing less than 6 mm is specific for tendon tear with 90% accuracy.

Nevertheless, in spite of a cuff tear, the static views may be normal or not reveal a diagnostic collapse of the subacromial space. The dynamic views allow cranial migration of the humeral head.

Dynamic techniques

Modified Leclercq maneuver - The modified Leclercq maneuver reveals the reduction of the subacromial space, revealing as such an indirect sign of a tear of the higher part of the cuff, especially the suprasinatus tendon. The maneuver can assess the extent of the tear, thereby obviating the need for arthrography or diagnostic MRI. However the latter proof remains justified in the preoperative set-up with regard to the site and extent of the tear. Recent studies have evaluated the modified "Leclercq maneuver". According to Rigal, the median value (± two standard deviations) of the subacromial space on films of opposed abduction in healthy persons is 9.5 mm (± 1.5 mm), 8.8 mm (± 1.4 mm) when there is a localized tear of the supraspinatus tendon and 4.6 mm (± 2.4 mm) (p = 0.0001) with associated tears of the supraspinatus and infraspinatus tendons. Following Cotty, the thickness of the acromiohumeral space is 10.5 ± 1.8 mm without any tear and 8 ± 2.5 mm with a tear. If a threshold value of the acromiohumeral space is fixed at 7 mm, the maneuver’s sensitivity varies, according to the different studies, from 62 to 81% and its specificity from 82 to 100%. The reduced thickness of the acromiohumeral space is considered diagnostic if it is greater than or equal to 4 mm compared with the static documents and 2 mm in comparison with the contralateral shoulder. It should be associated with a cranial migration of the humeral head higher than 3 mm in relation to the neutral position and opposite shoulder. The maneuver’s drawbacks are operator dependance, incomplete patient understanding of the maneuver that can prevent its correct application, and major shoulder pain eliciting false negative results.

True AP view in supine position (Railhac - Rigal) - The vertical beam perpendicular to the plane of the film investigates only the supraspinatus muscle and tendon. The AP view improves the detection of the rotator cuff tear or atrophy by the spontaneous cephalad migration of the humeral head, free from muscular and tendinous restraints and from the arm’s weight by the discharge. It also analyzes the morphology of the acromioclavicular joint, avoiding another specific view. Fourcade, Railhac and coworkers have done a prospective study on 57 patients with suspected, nonoperated cuff tears. The results were compared with routine arthrography data. Nineteen patients did not show any cuff lesion on arthrography; 23 patients showed a partial or isolated tear of the supraspinatus tendon; and 7 patients showed associated lesions of the supraspinatus and the infraspinatus tendons. For the associated lesions of the supraspinatus and infraspinatus tendons, the optimal discriminatory threshold of the subacromial space is fixed by the ROC curve; the latter is 6 mm wide, with a sensivity of 90% and a specificity of 90%. For the isolated supraspinatus tendon lesions, there is a relatively significant difference (p < 0.02) between the same group and the group with a tear but the overlapping of the observed measures makes analysis difficult in routine practice. For isolated suprasinatus tendon lesions, the modified Leclercq maneuver does not reveal any diagnostic difference in the thickness of the subacromial space compared with its thickness in a normal population.

Conclusions - In routine x-ray imaging of the rotator cuff, basic static views sometimes reveal the collapse or reduction of the subacromial space. They may be normal, however, and not reveal any diagnostic narrowing. The technique in the supine position sensitizes or detects the tear. The method is at least equivalent to, if not better than, the modified Leclercq maneuver, with the acromiohumeral collapse indicating a torn supraspinatus tendon. A normal x-ray presentation of the acromiohumeral space does not exclude a partial or complete cuff tear, which may be diagnosed by noninvasive techniques such as ultrasonography in the extra-acromial part of the cuff or MRI.

Diagnostic value of routine plain radiography in shoulder instability

Radiographic views and technique - In patients with a history of dislocation of the glenohumeral joint or chronic shoulder instability, a variety of radiographs can be obtained, in an effort to depict a fracture of the anterior glenoid rim (bony Bankart lesion) or a compression fracture of the humeral head either along the posterolateral aspect (Hill-Sachs lesion), or along the anteromedial aspect (MacLaughlin lesion). Although standard views are usually sufficient for diagnosing and analyzing these abnormalities, other projections have been described. If the arm cannot be abducted 90°, the first projection is through the lateral scapular view or Neer or Lamy’s true lateral view. Another projection is the axillary view. A third projection, proposed by the French radiologist Bernageau, is the glenoid profile. If the arm can not be abducted, the lateral scapular view and apical oblique projection described by Garth are useful. To obtain this image, the patient is placed in the 45° posterior oblique position relative to the x-ray tube with the uninjured shoulder rotated away from the cassette (which is held vertical if the patient is seated and horizontal if the patient is supine). The central beam is directed at a 45° angle to the coronal plane of the patient’s body and 45° caudad.

The accuracy of Garth’s apical oblique projection is 85% that of Bernageau’s glenoid lateral view. The 30° maximum angling of the remote-controlled tables offers another variant. With the trunk still kept rotated 45° towards the shoulder being examined, a descending beam angled at 30° and a 15° anterior incline of the thorax will discover the posteroexternal contour of the humeral head, lower angle of the glenoid, and the coronoid process positioned under the glenoid (Sintzoff). According to the rules of dynamic radiography, the stress views thus included the AC-joint view with loading of the upper extremity with 5 to 15 lb and drawer maneuvers. Mobilizing the humeral head under brilliance amplification comprises the anterior and posterior drawers in the glenoid profile in abduction with elevation so as to reveal any laxity. The anterior drawer in axillary view, or in the glenoid profile is achieved with the arm abducted and in retropulsion with external rotation, the posterior drawer with the arm in anterior flexion and abduction with internal rotation.

Additional techniques - Posterior dislocation of an immobilized shoulder is recognized by a descending (Bloom-Obata) or ascending retrohumeral profile showing the crush fracture of the anterior part of the humeral head (MacLaughlin’s notch).

Financial cost of a simple radiological examination - In Belgium, the maximum statutory health insurance reimbursement for studying a shoulder, regardless of the number of incident angles, is 512 Belgian francs (this is equal to 84 French francs). In France, in contrast, the reimbursement is 246 French francs for the first four films and FF10.92 for each additional view.

Radiation cost of simple radiological examination of the shoulder : Remark - The radiation exposure associated with a simple radiological examination of a scapulohumeral joint is a rough approximation. The actual doses absorbed in the room during examinations have never been measured, and the tube’s output in mBy/mAs is not known. The approximate calculation is based on a publication by the National Radiological Protection Board (NRPBR 262). The entry dose was taken to be a hypothetical value calculated from the data of 50 mAs and 75 kV, assuming the legally-required filtration of 2.5 mm A1. In this case, the doses correspond to a power of 75 kV, 2.5 mm A1 filtration, and an estimated entry dose of 2.1 mGy.

Shoulder

profile

AP view

effective dose

0.0087 mSv

0.080 mSv

skin dose

0.056 mSv

0.055 mSv

So, according to these estimates, in the case of a rotator cuff or a shoulder joint morphology study consisting of six films, the patient receives an effective dose of 0.401 mSv and a dose to the skin of 0.331 mSv. For an instability study, which involves four films per shoulder, the effective dose is 0.250 mSv and the dose to the skin is 0.165 mSv. These values are estimates, however. The actual values might be higher. A better assessment, which is contingent on knowing each tube’s exact power and filtration, must be made.

Elbow routine radiography - Imaging diseases processes in the elbow requires understanding of the anatomy and development of the joint and adjacent bone. Diagnosing conditions in the elbow calls for knowledge of the location and age of appearance of separate ossification centers. Medial epicondyle ossification center avulsion requires orthopedic fixation to avoid articular incarceration. In most cases, plain films provide sufficient information to make the correct diagnosis. The imaging needs for diagnosing abnormalities in and about the elbow are currently met in most instances by plain film radiography. If the plain radiographs are not diagnostic, several other modalities are available to the radiologist (they will be discussed in the next sessions). The plain films are potentially effective for diagnosing lesions of growth (Salter-Harris lesions); adult fractures; OCD fractures; dislocations. Periarticular opacities (either calcium deposits or tears of the tendon Sharpey fibers), and lateral, medial, or posterior impingement are not susceptible to radiographic diagnosis.

Radiographic views and technique - The routine radiographic examination of the elbow includes anteroposterior (AP) and lateral radiographs, with internal and external oblique views in many cases to better delineate the joint surfaces and adjacent bones. For the AP projection the hand should be in supination to prevent rotation of the forearm bones. On the oblique projections the coronoid process is usually clear of the radial head. For the lateral projection the elbow is flexed 90% and the hand is placed in the lateral position. The humeral epicondyles should be perpendicular to the plane of the film. The anterior fat pad may be normally seen or not seen on the lateral projection, whereas the posterior fat pad lies in the olecranon fossa and cannot be seen unless it is displaced by fluid in the joint space. A lateral radiograph using the horizontal beam technique may help identify lipohemarthrosis, which indicates that the patient has an intra-articular fracture or injury to the cartilage or ligaments. Additional views have been described that may be of use for evaluation of specific sites. These include an axial projection of the distal humerus and olecranon process to demonstrate better the epicondyles, trochlea, groove between the medial epicondyle and trochlea, and olecranon fossa. Axial projections of the radial head with the hand in supination and pronation allow visualization of the entire articular surface without bony superimposition.

A radial head capitellum view has been found to be helpful for demonstrating injury to the posterior half of the radial head, coronoid process, and capitellum. It is probably best used as an additonal view when there is a high clinical suspicion of a fracture or when displaced fat pads are seen without fracture outlined on routine radiographs.

Wrist routine radiography - The anatomy of the wrist is as complex as it is controversial. Wrist vocabulary is not standardized, ligament functions are debated, and the existence of some structures has been questioned. A host of normal variants adds to the challenge of imaging this difficult region. A static osseous pathologic state can often be demonstrated with plain radiographs. Fractures of the distal radius are among the most common orthopedic injuries, occurring in approximately 1 in 500 persons annually. They account for nearly one-sixth of all fractures seen in the emergency room each year. Fractures of the distal radius are more common in children between 6 and 10 years of age and in elderly women. At least in the elderly population, there is an association with proximal humerus and hip fractures. The traditional use of eponyms to describe distal radial fractures is imprecise and confusing, often leading to conflicting recommendations for treatment. As a result, numerous classification schemes have been developed to categorize fractures of the distal radius, providing a framework for the orthopedist regarding treatment options and outcomes. Current classification schemes organize fractures either by the presumed mechanism of injury or the anatomy of the fracture. Unfortunately, even though many modern classification systems exist, none of them describes all distal radial fractures completely. To date, no system has been universally adopted.

The recognition of static bony pathologic states can often be demonstrated with plain film radiographs. The identification of several dynamic pathologic conditions has fostered the development of an array of dynamic imaging techniques to demonstrate those conditions. In addition to the standard plain film examination and special projections, wrist imaging now encompasses dynamic motion studies, three-phase nuclide bone scans, routine and computed tomography, angiography, arthrography, and MRI. This arsenal provides the equipment to understand better problems in the wrist. Using these tools demands close cooperation betwen the examining clinician and radiologist to tailor an appropriate imaging protocol.

Radiographic views and technique - The routine evaluation of the wrist requires the following five views (5 views).

  1. Posteroanterior (PA) view. The standard PA view is taken with neutral forearm rotation. This is accomplished by abducting the humerus 90° from the chest wall and flexing the elbow 90°.
  2. PA view and ulnar deviation with the central beam angled 15 to 20° toward the elbow.
  3. Lateral view. This view is taken with neutral forearm rotation by maintaining the humerus adducted against the chest wall and flexing the elbow 90°. The ulnar side of the wrist and hand is maintained flat against the cassette, and there is straight alignment of the forearm with the dorsum of the hand. A better profile may be obtained by slight flexion at the wrist. The lateral view can also be taken with the arm abducted to the level of the shoulder, the elbow extended, and the forearm in a neutral position. On a properly positioned lateral view, the distal pole of the scaphoid should lie 4 to 5 mm anterior to the ventral surface of the pisiform. The radial styloid, scaphoid proximal pole, lunate, and triquetrum should be superimposed.

4-5.Oblique views. These are obtained with semisupination and semipronation (45° from the lateral position).

AP and lateral radiographs usually suffice to detect and characterize most traumatic and nontraumatic conditions. A semisupination and a semipronation oblique views are useful to evaluate metacarpal bone fractures. Semisupination oblique view or its variant, Brewerton’s view, can be used to detect metacarpal head fractures, collateral ligament avulsion injuries, and CMC fracture dislocations.

On occasion, evaluation of the injured wrist requires specialized views to detect carpal fractures. Carpal tunnel views profile the hook of the hamate, pisiform bone, and the latter’s articulation with the triquetrum. Elongated PA views of the scaphoid are taken with either 10 to 15° ulnar deviation or with the radial aspect of the hand raised 20° off the table, and with 20-to-35-degree cephalad beam angulation. A carpal boss view affords a tangential view of the dorsal carpometacarpal joints. A large number of additional views has been proposed, most of which are variations of the more standard PA and lateral views. These views may be obtained using standard radiographic techniques. However, it is often faster (and better alignment of the cortex and joints of interest can be obtained) if these views are acquired with a spot film device under fluoroscopic control. Fluoroscopy and digital radiography are variations of normal radiography that may be of value in selected cases. Discussion of the technique is beyond the scope of this presentation (there are many standard textbooks for further information).

Diagnostic rules - Gilula has defined a systematic analysis of the PA wrist that allows highly accurate identification of normal and abnormal intracarpal alignment. Using his system, one traces three arcs from proximal to distal. Arc I outlines the proximal margins of the scaphoid, lunate, and triquetral bones; Arc II, the distal margins of the same bones; and Arc III, the proximal margins of the capitate and hamate bones. Each of these arcs should be smooth and unbroken. Identification of discontinuities in the arcs with or without changes in carpal shape, e.g., a triangular appearance of the lunate or a focal change in joint width locates an area of abnormality. Other frontal, AP rules are greater and lesser arcs with regard to perilunate dislocation. Exceptions to this rule are the normal rounding of each carpal bone at joint margins and congenital variations in carpal bone shape, especially the proximal and ulnar surfaces of the triquetrum. When considering the PA and lateral wrist radiographs, seven radiographic measurements may be of importance. The first, radial angulation describes the relative angle of the distal radial articular surface on the PA view to a line perpendicular to the long axis of the radius. This angle should be between 15 and 25°; it averages around 20°. Loss of this angle indicates a distal radial fracture, with impaction or overlap of fragments in most cases. A second measurement of the distal radial articular surface alignment is made on the lateral view. As on the AP view, the relationship between the articular surface and a line perpendicular to the long axis of the radius yields an angle referred to as a palmar tilt. It is usually between 10 and 25°. The third measurement relates the length of the radius to that of the ulna, commonly called "ulnar variance." Most often, it is made on the PA film by comparing the two bones’ lengths at their articulation with the lunate, where they are at relatively the same level. If the ulna is short, the term negative ulnar variance is used. In reviewing the literature, one finds considerable inconsistency in data relating to ulnar length. The positions of the upper arm and forearm influence the relative lengths of the radius and ulna at the wrist because pronation causes the radius to cross over the ulna, making it appear shorter. More than 2 mm difference in apparent radial length can be seen between radiographs of the wrist in full pronation and in full supination if the elbow position is held constant.

When abnormal lunate tilting is suspected, as seen in DISI or VISI, two axes and two angles should be drawn on the neutral lateral view. The fourth measurement is the " central " lunate axis. It may be drawn reproducibly by joining the distal dorsal and ventral lunate poles with a dashed line and drawing an axis line perpendicular to this line. This axis will not be a true central axis dividing the lateral lunate area in all cases, because the lunate is usually larger in its ventral than its dorsal half and therefore may not be a perfect half moon. However, this axis line is reproducible from examination to examination. The fifth measurement is the scaphoid axis. It can be drawn by joining the distal and proximal ventral convexities of the scaphoid by a tangential straight line. This line serves as a reproducible axis of the scaphoid, because this line is parallel or nearly parallel to the midplane of the scaphoid. Because these two scaphoid convexities can be detected in any adequately positioned lateral wrist view, this method is easier to use as an indicator of the scaphoid axis than trying to trace the entire circumference of the scaphoid on the lateral view. The sixth measurement is the radiolunate angle (10 - 25°) and the seventh the scapholunate angle (30 - 70°). Many additional measurements of the relative position and angulation between carpal bones have been made. Most of these describe the relative angles between bones on the lateral view and are valuable in identifying ligamentous injuries and chronic carpal instabilities. Considerable controversy exists as to the value and reproducibility of these measurements.

Wrist motion study - With disruption of the scapholunate interosseous ligament or disruption of the strong volar carpal ligaments, a gap may occur between the scaphoid and lunate bones. This abnormality may be accentuated by applying tension to the scapholunate interosseous space by flexing the hand in the ulnar direction. Because this may not be apparent on the unstressed plain film examination, stress views are necessary to confirm this diagnosis. The assumption of the positions that constitute the wrist motion study effectively and selectively stresses each intracarpal ligament. With wrist motion, one may normally see gliding of the carpal bones on each other. The strong ventral radiocarpal and ulnocarpal ligaments and the weak dorsal ligaments provide most of the static wrist stability.

Posteroanterior views in full radial and ulnar deviation and with radial and lunar translation stress are obtained to judge intracarpal and radiocarpal motion. Similary, flexion, extension, dorsal and ventral stress and radial and ulnar deviation views are obtained in the lateral projection. In the PA position with ulnar flexion, tension is applied to the radial side of the wrist. With instability of the scapholunate interosseous ligament and the associated ligamentous complex, one may see widening of that joint space. Alternatively, when the hand is flexed in the radial direction, tension is applied to the ulnar side of the wrist. With instability of the lunotriquetral interosseous ligament and the associated ligamentous complex, one may see slight widening of that joint space. With the wrist in the position of neutral rotation and the fist tightly clenched, the capitate is driven into the proximal carpal row. Instability of either the scapholunate or lunotriquetral interosseous ligaments may cause widening of those spaces. The important observation made on the PA radiograph is the lack of variability of space between the carpal bones despite the various wrist positions obtained. In the normal wrist with motion, one should not see widening of an intracarpal space. The identification of that abnormality indicates ligamentous abnormality.

The wrist motion examination additionally includes visualization of the wrist in the lateral position with flexion and with extension. Normally, with those motions, the wrist traverses an arc of 120°. Approximately one third of that motion occurs at the articulation of the lunate bone with the radius, and two thirds occur at the articulation of the capitate and lunate. With generalized wrist pain, proportional reduction of wrist motion occurs at those two sites. With a localized abnormality, the reduction in motion with flexion and extension may be limited to the lunate’s articulation with either the radius or the capitate bone. The wrist is additionally observed in the lateral position with ulnar flexion and with radial flexion to assess the axial relationship of the scaphoid and lunate bones. The important observation made on the lateral radiograph is the relationship of the axes of the scaphoid and the lunate bones during these maneuvers as well as the axial relationship of the capitate and lunate bones.

At least six static carpal ligament instabilities have been described. They are dorsiflexion instability, or DISI (Dorsal Intercalated Segmental Instability), palmar flexion instability, or VISI (Ventral Intercalated Segmental Instability), rotatory scaphoid subluxation, ulnar translocation, dorsal carpal subluxation, and palmar carpal subluxation. The first two, dorsiflexion and palmar flexion instability, are the ones that are the most difficult to understand and remember; however, review of a few features should make these readily discernible.

Normally, with the wrist in neutral alignment, the lunate is positioned within the distant articulating fossa of the radius with the lunate axis remaining within 10° of the long axis of the radius. Instability patterns exist causing the lunate to tilt volarly or dorsally. Dorsal instability of the lunate, or dorsal intercalated segmental instability, indicates a condition in which the distal articulating surface of the lunate is inclined dorsally. Frequently, the scaphoid is simultaneously inclined volarly. In this condition, the intersection of the axes of the scaphoid and lunate bones usually subtends an angle of greater than 80°. Alternatively, the distal articulating surface of the lunate may be inclined in the volar direction, indicating a volar instability pattern, or volar intercalated segmental instability. In this circumstance, the intersection of the axes of the scaphoid and lunate bones subtends an angle of less than 30°. With these instabilities, the scaphoid and lunate bones move independently rather than in consort, and patients complain of wrist pain sometimes associated with a clicking sensation. The late development of carpal degenerative arthritis usually results.

Rotary scaphoid subluxation (or perilunate dislocation) may be easy or hard to detect, depending on the position of the scaphoid at the time of the wrist radiographic exposures. Fluoroscopic examinations with or without videotape capabilities that consist of watching motion between radial and ulnar deviation while profiling the scapholunate joint in both the pronated and supinated positions may be readily used to observe smooth or irregular intercarpal motion and especially transient scapholunate diastasis. Fist compression may also be applied during radial and ulnar deviation if desired. The other three carpal ligament instabilities are recognized by remembering that they do exist. The radiographic key to recognizing any of these carpal instabilities (except for scaphoid rotary subluxation) is to identify the position of the lunate. On the lateral view, see if the lunate is tilting ventrally (VISI) or dorsally (DISI), or if it is displaced dorsally (dorsal carpal subluxation) or palmarly (palmar carpal subluxation) more than one would suspect. On the PA view, ulnar displacement of the carpus (ulnar translocation) can be readily identified.

One dynamic ligament alteration concerns capitatolunate instability which is characterized by excessive laxity of the supporting ligaments of the capitate, which allows subluxation of the capitate with appropriate force. This requires that the carpus be visualized in the lateral position. With dorsally or volarly directed force, the capitate subluxes out of the distal lunate fossa. Manual traction is necessary to make this diagnosis. When that force is released, the capitate snaps back into alignment, causing pain similar to that which led to the examination. Sometimes this may simply reflect underlying generalized ligamentous laxity. In persons, however, in whom this is a unilateral finding involving only the symptomatic wrist, capitolunate instability is the correct diagnosis.

Early in embryonic development the carpus develops as a single block of cartilage that later undergoes cavitation into joint spaces. This occurs at approximately the 30-mm stage of development. Cavitation progresses from the preaxial (radial) side of the wrist toward the ulnar side. Occasionally, joint cavitation is incomplete and bony coalition occurs, lunotriquetral coalition being the commonest residual feature of this phenomenon. This feature may be associated with slightly reduced wrist motion but is otherwise asymptomatic. Joint arthrography occasionally demonstrates lack of communication of the pisotriquetral joint with the rest of the radiocarpal joint. This anatomic variation lacks clinical symptomatology.

Conclusions - Plain film radiography currently meets the imaging needs for diagnosing osseous and joint abnormalities in and about the shoulder, elbow and wrist in most instances. Conventional x-ray does not allow visualization of tendon and bursal structures and is therefore insensitive in the detection of all but large rotator cuff tears. Plain films are very useful in demonstrating traumatic conditions, intra-articular loose bodies, fractures (and including clinically unsuspected), compression, avulsion, dislocation, instability; AVN stage 3, post-traumatic OA; or nontraumatic conditions, morphologic abnormalities, OA, RA, SPA, HA deposition disease, infections and tumors. Imaging disease processes in and around the elbow requires an understanding of the anatomy and the development of the joint and adjacent bone. In most cases plain radiography provides sufficient information to make the correct diagnosis, i.e. lesions of growth (Salter-Harris lesions), adult fracture, OCD fracture, dislocation. With regard to the wrist, although most static abnormalities may be nicely displayed on routine plain films and special projections, many dynamic abnormalities require motion or stress views to demonstrate their presence. The real question is, can an imaging technique itself provide new and unique information that changes the diagnostic and therapeutic approach to upper extremity joint disease?

Reference

  1. Rupture de la coiffe des rotateurs. Quantification des signes directs et indirects en radiologie standard et manoeuvre de Leclercq. J. P. Cotty , Proust et al. Radiol., 69, 633-638, 1988.

  2. Rupture de la coiffe des rotateurs. Valeur diagnostique du cliché standard en abduction contrariée (manoeuvre de Leclercq) dans l’epreuve douloureuse chronique. P. Cotty, D. Fouquet et al. Rev. Im. Med. 6, 43-47, 1994.

  3. Surgery of the shoulder 3d ed. A.F. De Palma. Philadelphia, Lippincott, 211-241.

  4. The "Hooked" acromion revisited. J.G.J. Edelson. Bone Joint Surg 77-B, 284-287, 1983.

  5. Les clichés dynamiques : mesure du pincement sous acromial. D. Fourcade, J.J. Railhac J et al. In "The Cuff" Grazielly D., Elsevier Ed. Paris, 1996.

  6. Imaging of the elbow. R.C. Fritz, L.S. Steinbach, P.F.J.Tirman, S. Martinez. MR Radiol. Clin. North Am. 35, 117, 1997.

  7. Imagerie médicale des lésions traumatiques du poignet. E. Fumière, S. Sintzoff. Ed Juridoc - Bruxelles 4, 113-130, 1998.

  8. Imaging of acute injuries to the wrist and hand. T.J. Gilbert, M. Cohen. Radiol. Clin. North Am. 35, 701-707, 1997.

  9. Imagerie des lésions traumatiques du coude. D. Godefroy, S. Sintzoff. Ed Juridoc Bruxelles 4, 39-59, 1998.

  10. Valeur des radiographies standard pour le diagnostic de rupture de la coiffe des rotateurs de l’épaule. P. Goupille, C. Anger et al. Rev. Rhum. 60, 440-444, 1993.

  11. Categorization of acromial shape : interobserver variability with MR imaging and conventional radiography. T.M. Haygood, C.P. Langlotz, J.B. Kneeland, J.P. Iannotti, G.R. Williams, M.K. Dalinka. AJR, 162, 1377-1382, 1994.

  12. Roentgenographic diagnosis of shoulder dysfunction. G.A. Kernwein. JAMA, 194, 179-183, 1965.

  13. Osteoarthritis of the glenohumeral joint in radiological pathologic study. R. Kerr et al. AJR, 144, 967-972, 1985.

  14. Magnetic resonance imaging of the shoulder. S. Kursunoglu-Brahme and D. Resnick. Radiol. Clin. North Am. 28, 941-947, 1990.

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Virtual Reality based on Conventional X-rays

Ph. Van Ham1, T. Leloup1, N. Lasudry-Warzée1, F. Schuind2
1 Faculté des Sciences Appliquées, Service des Systèmes Logiques et Numériques, Université libre de Bruxelles, Brussels, Belgium
2 Department of Orthopaedic Surgery, Erasme University Hospital, Université libre de Bruxelles, Brussels, Belgium

Many surgical techniques require the acquisition of intraoperative images. Brilliance amplifier (scope) is often used but implies high irradiation to the patient and the surgical team, the visual field is limited and images are distorted. Moreover, a great number of images is often required because they only give two-dimensional information at a given time.

Using a small number of conventional x-rays, it is possible to build basic 3D-models of rigid anatomical structures which are often sufficient for the surgeon. To obtain a dynamic 3D-view, markers can be fixed to these structures and followed by an optical localizer system during manipulations effected by the surgeon. This dynamic 3D-view is continuously available without irradiation.

An application of this technique has been developed to visualize the reduction of a diaphyseal fracture treated by external fixation. Two orthogonal radiographs of the injured limb are taken (lateral and PA views). The plane of projection and the x-ray source are localized with a 3D-digitizing pointer for both views. The contours of the fragments are determined on both radiographs, and a 3D-model is built for each principal fragment. The pins inserted in each fragment are used to support three markers (IR diodes). During the reduction, an optical tracker follows the position of the markers and allows display of the fragments models in virtual reality. This system supplies a dynamic 3D-image of the fracture which can be visualized from any viewpoint. The radiation exposure of the surgical team is considerably decreased. The brilliance amplifier could then be replaced by such a virtual reality system to provide the surgeon with an accurate tool which facilitates the reduction of the fracture.

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Rotator Cuff Tendinopathy and its Spectrum of Disease detected by Ultrasound

M. van Holsbeeck1, J. Introcaso2
1 Department of Diagnostic Radiology & Rehabilitation, Henry Ford Hospital, Detroit, Michigan, USA
2 Lutheran General, Chicago, IL, USA

The Etiology of the Disease - Tendon rupture may occur in association with little or no trauma. These tendon ruptures occur at sites of tendon degeneration, which significantly weaken the tendon. The best example of this type of tendon rupture involves the rotator cuff of the shoulder. The impingement theory has long been cited as the cause of the majority of rotator cuff tears [14]. However, recent epidemiologic and pathologic evidence points toward aging as the most important factor in the pathogenesis of rotator cuff tears [5,10,12,15]. Our studies indicate that hand dominance and physical activity do not increase the incidence of rotator cuff tears [12].

Many patients relate a cause and effect relationship between an event with minor trauma and the onset of their shoulder problems. The associated incidents vary from throwing a bail to falling on an outstretched arm, or even playing at a card game. These events may simply be the final event in a long series of minor traumatic events, which result in tendon degeneration and progressive ‘rotator cuff fiber failure’. Matsen [10] describes the process of chronic rotator cuff injury as an insidious process which goes unnoticed by the patient and bas been referred to as ‘creeping tendon ruptures’ [21].

Asymptomatic rotator cuff tears affect a large portion of the population, as many as 60 percent of individuals over 60 years of age [12]. As we age, the rotator cuff becomes increasingly susceptible to rupture with less force required to result in tendon injury. Significant force is required to tear the rotator cuff of a 30-year-old, while relatively trivial force is needed to produce a tear in a 60-year-old. When a group of tendon fibers fail at the same time fixe lesion becomes symptomatic, presenting as rest pain exacerbated by extension, abduction and external rotation. Acute extension of fixe tear may occur, associated with fixe sudden onset of substantial weakness in flexion, abduction and external rotation.

Although differences of the acromial shape, abnormalities of the acromioclavicular joint and other factors may influence the susceptibility of the rotator cuff to tears, age related deterioration appears to be the dominant factor [21]. Age related tendon degeneration and loading factors are dominant in determination of patterns of failure of the rotator cuff.

Patterns of degeneration - Tendon degeneration in the rotator cuff is a process which appears to begin at the age of 30. Post-mortem studies have shown that this process begins interstitially.

In both clinical and cadaver studies, we have observed two distinct patterns of partial thickness rotator cuff tears [20]. The first type is a lesion of mixed echogenicity, with separate regions of decreased and increased echogenicity. These lesions are typically identified along the articular (deep) surface of the tendon. A hyperechoic linear or curvilinear cleavage plane is outlined by a hypoechoic halo. This interface may relate to the retracted tom tendon fibers.

The second type of partial rotator cuff tear is homogeneously hypoechoic or anechoic. Typically, these tears are located either centrally within the tendon or along the bursal surface. The region of decreased echogenicity represents fluid in the majority of cases, but may be due to myxoid degeneration.

Delamination within the critical zone of the rotator cuff is the most common pathologic finding in autopsy studies [2,3]. As degeneration occurs, resulting in delamination, the retracted longitudinal fibers of the supraspinatus tendon result in a comma shaped hyperechoic defect. The art of rotator cuff sonography requires the examiner to distinguish between artifact resulting from the normal interface of tendon layers [1] and a true lesion caused by disruption of tendon fibers in the critical zone. Artifact will be transient, disappearing with angulation of the transducer. A true lesion will remain visible despite slight variation in the angle of incidence of the sound beam. Calcifications appear as echogenic interfaces as well. However, they appear more round or spherical in stead of the linear or stub-like interfaces of the partial-thickness tear.

Many full thickness rotator cuff tears result from propagation of partial thickness tears. These lesions are typically located in the critical zone of the supraspinatus tendon, about one centimeter proximal to the lateral-most extent of the tendon insertion on the greater tuberosity. Small full thickness tears in the critical zone are referred to as horizontal full thickness tears. They typically uncover the greater tuberosity and result in an irregular bone surface. These lesions are beat visualized on longitudinal images. It is helpful to observe the continuity of the bursal interface; discontinuity of this interface indicates bursal extension of rotator cuff disease. On transverse images these lesions may be misdiagnosed as partial thickness tears due to partial volume effect caused by the crystal width in the footprint of the transducer.

Longitudinal full thickness rotator cuff tears extend along the length of the tendon and are observed less frequently than horizontal tears. Tears of this type more likely result from an acute traumatic injury. The proximal extent of the tear uncovers the articular cartilage of the humeral head. Differences in the acoustic properties between the fluid filling the tendon defect and the articular cartilage result in a sharp highly echogenic interface. We refer to this as the cartilage interface sign, which is characteristic of large longitudinal rotator cuff tears.

Important secondary signs - Secondary signs of rotator cuff pathology will also lead the examiner to the correct diagnosis. Synovitis [7,11] and degenerative changes in the cortical bone of the greater tuberosity [22] are excellent indicators of associated rotator cuff pathology. Often synovitis is associated with fluid, which can extend into the bursa, joint space or biceps tendon sheath. The hypoechoic thickening of the bursa is not always due to an effusion, synovial proliferation is sometimes difficult to differentiate.

Degenerative bony changes occur along the surface of the greater tuberosity, which is left bare by the tom tendon fibers. These erosions may also be seen along the anatomic neck of the humerus. Dr. Codman was the first to describe these bony changes observed in autopsy specimens [2,3]. These findings were subsequently confirmed by other investigators in radiographic studies [6], arthrography [17], and sonographically [16,20,22]. Our recent studies have confirmed the importance of identifying these secondary findings. Bony changes are associated with both partial and full thickness tears of the rotator cuff, seen in as many as 70% of cases [22]. They are always identified at the site of the cuff lesion and the sire of the bony lesion corresponds very closely with the size of the rotator cuff tear. Both bone erosion and proliferation occur in combination at the site of the lesion. The degree to which each process occurs varies widely from one patient to another. In some osteolysis will predominate and in others bone proliferation will be the dominant reaction. This pattern of osteolysis and bone proliferation resembles that seen at fracture sites. Therefore, we feel that these lesions are post-traumatic. Neovascularity can be observed both histologically and sonographically in association with these lesions. These vascular changes are similar to those observed at healing fracture sites and with Ilizarov bone lengthening procedures.

Bony changes and their associated neovascularity are very helpful secondary signs of rotator cuff tears. Even the earliest partial thickness tears are often associated with bony changes. Often this can help in distinguishing artifact from true partial thickness tears.

Significance of finding a tear - Many rotator cuff tears are completely asymptomatic, as demonstrated by a number of screening studies. It is not clear what factors determine which lesions will become painful. The sire of the tear alone dons not seem to be the factor determining if a pain syndrome results. Very large tears may remain asymptomatic, while small tears can cause disabling pain. A recent sonographic screening study of 100 volunteers discovered a high incidence of rotator cuff tears in pain free shoulders [12]. In addition, many of these patients had small effusions in either the biceps tendon sheath or the subacromial-subdeltoid bursa. Similar results have been reported in the MRI literature when examining normal shoulders [13,18,19]. This high incidence of rotator cuff tears has been confirmed in several cadaver studies [4,8,9]. Therefore, the clinical significance of rotator cuff findings must be carefully evaluated in patients over the age of 50 years. In these cases, clinical judgement is the most important factor in distinguishing asymptomatic from symptomatic rotator cuff lesions. The sonographic identification of a rotator cuff tear should not stop the clinician from considering other possible causes of shoulder pain. In addition, the sonographic examination should always be interpreted in conjunction with conventional radiographs. In an older patient population it is not uncommon to discover evidence of osseous metastases, myeloma or a Pancoast tumor on the radiographic examination. Limited range of motion and pain on shoulder elevation can be due to a number of disease processes, of which rotator cuff disease is the most common. However, simultaneous occurrence of a full thickness rotator cuff tear with a concurrent neoplasm involving or adjacent to the shoulder is not rare in our experience.

Our imaging strategy - Patients with rotator cuff disease will usually consult their primary care physician or may present to the emergency room with a history of pain following acute trauma. Iii most cases a radiograph will be obtained and is usually interpreted as normal. The patient will often be assured that ‘nothing is wrong’ with the shoulder and be sent home with a prescription for a non-steroidal anti-inflammatory agent. It has been postulated that tendon fiber failure will continue with recurrent episodes of pain associated with microtrauma [10]. The patient is finally referred to an orthopedic surgeon after enduring pain for months or even years. At that point the patient is so uncomfortable that he/she is willing to submit to invasive diagnostic studies, such as arthrography, MR arthrography and even arthroscopy. The cuff changes identified at this late stage are often full thickness and some are inoperable due to the extent of the tear. Clearly there is a great need for non-invasive diagnostic imaging utilized earlier in the disease process. It is not usually necessary to perform more than one conventional radiographic examination of the shoulder prior to sonographic evaluation of the rotator cuff. The ultrasound examination may be performed on the patient’s initial visit, following radiography. This strategy would eliminate repetitive radiographic examinations and expedite the patient’s therapy, resulting in significant cost savings.

References

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Shoulder, Elbow and Wrist MRI

L.S. Steinbach
Department of Radiology, University of California, San Francisco, USA

Abstract not received in time

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MR-Arthrography : Current Indications

M. Shahabpour, M. De Maeseneer, M. Osteaux
Department of Radiology, AZ VUB, Brussels, Belgium

The use of MR-arthrography (MRA) as a supplement to standard MR imaging of the joints is not currently accepted. It seems evident that fluid present within the joint leads to more optimal visualization of numerous intra-articular structures.

Materials and methods - There are two main methods to perform MRA. The direct method consists of intra-articular injection of contrast material (saline, iodinated agents and gadolinium). The indirect method corresponds to intravenous injection of a gadolinium-containing compound, followed by delayed imaging (about 15 - 20 minutes, after exercising the joint).

The concentration of gadolinium for MRA varies between 500 µmol/L - 2 mmol/L. Approximately 1 ml of gadolinium is mixed with about 200-250 ml of saline and a small amount of iodinated contrast material; the amount of volume injected varies from one joint to another (30 ml for the knee, 15 or 20 ml for the shoulder, 3 ml for the wrist - best under fluoroscopic monitoring).

Subsequently, standard spin-echo (with and without fat suppression) and gradient-echo sequences can be performed. Since the government in our countries (the Federal Drug Administration in the States) has not approved the intra-articular use of gadolinium-containing agents, local hospital approval must be obtained.

Main applications of MR-arthrography - They include the analysis of capsulolabral structures and articular cartilage (in the assessment of shoulder instability) and the detection of intra-articular bodies. It may be useful in the diagnosis of partial tears of the undersurface of the rotator cuff and for small full-thickness tears (in absence of native fluid). In the operated knee, it can be used for assessment of the surface of the resected meniscus. Additional indications exist in the wrist, elbow, ankle, hip and other joints. The intra-articular injection of a gadolinium-containing agent may provide better visualization of the surface of articular cartilage and better assessment of osteochondritis dissecans when compared to standard MRI. Specific patterns of contrast extravasation are diagnostic of ligamentous lesions on the medial or lateral aspect of the elbow and ankle joint. MRA can also be used in assessment of the acetabular labrum in the hip joint.

With regard to glenohumeral joint instability, the benefits of MR arthrography relate mainly to distention of the joint cavity, allowing more accurate analysis of the glenoid labrum (including SLAP lesions) as well as the glenohumeral ligaments. This technique may be combined with a positioning method in which the arm is abducted and externally rotated (ABER position).

Conclusion - Intra-articular addition of contrast can improve the diagnostic value of MRI, in the absence of native joint fluid. The disadvantages of MRA include the conversion of a noninvasive to an invasive examination, and an increase in length and in cost of the examination. At this time, MR-arthrography should be used selectively when results of other imaging examinations, including standard MR-imaging, are not conclusive. Further studies investigating its cost effectiveness are required.

Reference

Internal derangement of joints. Emphasis on MR imaging. D. Resnick and HS Kang. Saunders Philadelphia 1997 p. 951.

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