MEDLINE Abstracts: Superior Labral Tears in Shoulder Instability

June 05, 2002

MEDLINE Abstracts: Superior Labral Tears in Shoulder Instability

What's new concerning the role of superior labral tears in shoulder instability? Find out in this easy-to-navigate collection of recent MEDLINE abstracts compiled by the editors at Medscape Orthopaedics & Sports Medicine.

Bresler F, Blum A, Braun M, Simon JM, Cossin M, Regent D, Mole D
Surgical & Radiologic Anatomy 20(1):57-62, 1998

The ability to detect and categorize SLAP (Superior Labrum Anterior to Posterior) lesions of the scapular labrum is of practical importance to the orthopedic surgeon and the radiologist. The aim of this study, performed on cadaveric shoulders, was to determine whether CT arthrography or MR arthrography is able to show normal anatomical variation of the glenoid labrum and detect labral abnormalities. CT arthrography, MR arthrography followed by anatomical dissection were performed on twenty three fresh frozen cadaveric shoulders and analysed by a radiologist and two orthopaedic surgeons. As Gadolinium intra-articular injection is not allowed in France, we used an iodinated contrast media for both MR arthrography and CT arthrography. In this study, the sensitivity of MR arthrography seemed higher than CT arthrography (respectively 4 and 3 labral lesions diagnosed out of five), although no significant statistical conclusions can be made due to the small number of cases. In conclusion, under such specific conditions, MR arthrography seems to be the method of choice for the detection and classification of labral lesions.

Kreitner KF, Botchen K, Rude J, Bittinger F, Krummenauer F, Thelen M
AJR. American Journal of Roentgenology 170(3):599-605, 1998 Mar

Objective: The purpose of this study was to analyze the anatomic relationship between the superior labrum, the superior glenoid rim, the superior glenohumeral ligament, and the long head of the biceps tendon.
Materials and Methods: Seventeen cadaveric shoulder specimens underwent axial, oblique coronal, and oblique sagittal MR imaging on a 1.5-T imager. Unenhanced proton density- and T2-weighted spin-echo images with and without fat suppression, and T1-weighted fat-suppressed spin-echo images after intraarticular injection of gadolinium, were obtained of each specimen. The shoulders were then frozen and sectioned into 4-mm-thick slices, either transversely or oblique coronally. After gross anatomic correlation, histologic analysis was performed on 32 sections.
Results: A sublabral recess was present in 12 (71%) of 17 shoulders. MR arthrography was significantly better at showing the sublabral recess than was unenhanced MR imaging. Histologically, the synovial recess in all cases was covered by synovial lining cells. Intralabral altered histologic patterns were found in 20 (63%) of 32 labral sections. In addition to signs of degeneration, five sections of two specimens showed proliferating fibroblasts and vessels, as well as fibrosis, suggesting trauma. The presence or absence of altered intralabral histologic patterns was better assessed with T1-weighted fat-suppressed arthrograms than with unenhanced MR images. We found a close association grossly and histologically between the superior labrum and the biceps tendon.
Conclusion: The attachment of the superior glenoid labrum to the glenoid rim shows great variability. In MR imaging, an overlap appears to exist between physiologic recesses of the superior labrum and a type 2 superior labrum anterior-posterior lesion. T1-weighted fat-suppressed MR arthrograms provided the best view of the superior labrum and the labral-bicipital complex.

Nidecker A, Guckel C, von Hochstetter A
European Journal of Radiology 25(3):177-87, 1997 Nov

Lesions of the long head of the bicepstendon (BT) are seen in association with tears of the rotator-cuff, particularly lesions of the subscapularis tendon and the rotator-interval. The frequency of positive MR-findings at the BT is approximately 25%. The pathologic alterations include complete medial luxation, subluxation and entrapment by the subscapularis tendon, tendinitis or tendovaginitis and lesions at the origin of the tendon at the superior labrum (superior labrum anterior to posterior (SLAP) -- lesions). The imaging signs of BT pathology on MR include an abnormal course and position of the tendon, alterations in shape and changes in signal-intensity (SI), obliteration and thickening of the tendon-sheath. In long standing intra-articular BT rupture, neo-insertion of the tendon in the bicipital sulcus may ensue. The long BT needs to be visualized in transaxial, coronal oblique and sagittal oblique projections. Besides serving as stabilizer of the long head of biceps muscle, the BT is also an important stabilizer of the anterior joint capsule.

Gartsman GM, Taverna E
Arthroscopy 13(4):450-5, 1997 Aug

To evaluate the incidence of associated glenohumeral lesions in patients with a full-thickness rotator cuff tear, an arthroscopic examination of the glenohumeral joint was performed in 200 shoulders in 195 consecutive patients before arthroscopic rotator cuff repair. One hundred twenty-one (60.5%) had coexisting intraarticular abnormalities. Ninety-six (48%) had minor abnormalities, and 25 patients (12.5%) had major coexisting intraarticular abnormalities. Major lesions (that required operative treatment, changed postoperative rehabilitation, or altered the expected end result) noted at arthroscopic examination were osteoarthritis in nine patients, partial biceps tendon tears in three, labrum tears in three, Bankart lesions in two, superior labrum anterior posterior lesions in five, and glenohumeral synovitis in three patients. Glenohumeral arthroscopy can provide valuable information in patients with a complete rotator cuff tear.

LaBan MM, Gurin TL, Maltese JT
American Journal of Physical Medicine & Rehabilitation 74(6):448-52, 1995 Nov-Dec

The shoulder's unique wide range of motion is largely restrained by the articular capsule and the external ligaments of the glenohumeral joint. Internally, the long head of the biceps tendon passes within the capsule and inserts on the superior lip of the glenoid labrum. Trauma distracting this tendon can tear the superior glenoid labrum, producing the superior labrum anterior to posterior (SLAP) syndrome. Four patients, two of whom were female, presented with complaints of acute shoulder pain associated with weakness in abduction and forward flexion. Routine shoulder roentgenograms were normal. Magnetic resonance imaging (MRI) studies revealed a superior glenoid labral tear consistent with a SLAP syndrome. The superior labrum, unlike the firmly bound inferior portion, is loosely attached to the glenoid fossa. This inherent mobility predisposes it to disruption. To routine ultrasonography and arthrogram, the superior labrum may be obscured by superimposed structures. Shoulder arthroscopy, computed tomography, arthrography, and MRI have relatively equal sensitivity in visualizing these labral tears. The SLAP lesion accompanies 16% of all rotator cuff tears, occurring more often than heretofore recognized. When clinically suspected, they can be readily visualized by a noninvasive MRI examination.

Maffet MW, Gartsman GM, Moseley B
American Journal of Sports Medicine 23(1):93-8, 1995 Jan-Feb

The detachment of the superior labrum from anterior to posterior has previously been reported. This lesion has been classified into four types. It was our impression that not all superior labrum abnormalities fit into such a classification system and that the mechanism of injury was distinctly different. During a 5-year period, 84 of 712 (11.8%) patients had significant labral abnormalities; 52 of 84 patients (6.2%) had lesions that fit within the classification system (Type II, 55%; III 4%; IV, 4%), but 32 of 84 patients (38%) had significant findings that could not be classified. These unclassifiable lesions fit into three distinct categories. Two of three patients described a traction injury to the shoulder. Only 8% sustained a fall on an outstretched arm; 75% had a preoperative diagnosis of impingement based on consistent history and provocative testing; however, when examined under anesthesia, 43% of the shoulders were considered to have increased humeral head translation when compared with the other shoulder. Recognition of superior labrum-biceps tendon detachment should prompt the surgeon to investigate glenohumeral instability as the source of a patient's complaints.

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