Monday, February 9, 2009

Review of Labral Tears of shoulder

The glenoid labrum of the shoulder has extensive anatomic variation but appears to be important for contributing to shoulder stability and for increasing the depth of contact between the glenoid labrum and the humeral head. Tears of the labrum are commonly seen in association with other pathologic entities, such as instability and rotator cuff tears, and treatment of the labral pathology may be incidental to treatment of the other more significant pathology. However, conditions isolated to the labrum do occur and can be a significant source of shoulder problems. Effective treatment of these lesions may result in significant improvement in the patient's symptoms (4).
Labral lesions are difficult to diagnose, and special diagnostic studies and, frequently, arthroscopy are required. How much we can rely on clinical tests is a question. Shoulder complaints are frequently recurrent. Instability might cause some of these complaints (3). History taking and clinical tests are commonly used to diagnose shoulder pain. It is unclear, whether tests and history accurately diagnose instability or intra-articular pathology (IAP) (3).
3 different tests designed specifically to detect superior labral anterior posterior lesions (the resisted supination external rotation test, the crank test, and the active compression test) (2).
Luime JJ et al analyzed the accuracy of clinical tests and history taking for shoulder instability or IAP. They suggested, best evidence supports the value of the relocation and anterior release tests. Symptoms related to IAP (labral tears) remain unclear. Most promising for establishing labral tears are currently the biceps load I and II, pain provocation of Mimori, and the internal rotation resistance strength tests (3).

The resisted supination external rotation test (RSER), helps for the diagnosis of superior labral anterior posterior lesions of the shoulder. RSER test by re-creating the peel-back mechanism, the resisted supination external rotation test is more accurate than 2 other commonly used physical examination tests designed to diagnose superior labral anterior posterior tears in overhead-throwing athletes (2).
The SLAP test: (SLAP apprehension test) is performed by suddenly internally rotating the shoulder as the shoulder is adducted 300 in 900 of forward flexion. A positive test is noted with clicking in the shoulder and/or pain radiating down the biceps tendon or in the posterior aspect of the joint.
Crank Test: To identify a labral tear, Liu and colleagues described the crank test, executed by internal and external rotation of the shoulder in maximum forward flexion, with an axial load along the humerus. Although the numbers of patients in their study is insufficient to test the validity of the test, they found that six patients who had positive crank tests all had labral tears, and no patient with a negative crank test had a labral tear.
OBriens Test: O'Brien's active compression test was primarily developed for assessment of Acromioclavicular joint pathology following a patient's demonstration of what reproduced their shoulder pain. O'Brien noted in a series of patients it was also excellent for detecting labral pathology.
The patient is instructed to flex their arm to 90° with the elbow fully extended and then adduct the arm 10-15°medial to sagittal plane. The arm is then maximally internally rotated and the patient resists the examiner's downward force. The procedure is repeated in supination. The O'Brien Test is designed to maximally load and compress the ACJ and superior labrum. For maximal results the authors stress that the patient should resist the examiner's downward force rather than the examiner resisting forward flexion.

The O'Brien and crank tests were not sensitive clinical indicators for detecting glenoid labral tears and other tears of the anterior and posterior labrum. Results were often falsely positive for patients with other shoulder conditions, including impingement or rotator cuff tears (5).

What if the clinician suspects a labrum lesion but could not clinically rely on the clinical test?:
However, lesions of the superior labrum are complex and difficult to both diagnose and treat effectively. The clinical diagnosis is challenging due to the nonspecific history and physical examination. MRI has substantially improved our ability to detect SLAP tears, although experience is necessary to distinguish pathologic findings from normal anatomic variants. Treatment is determined by patient age, functional demands, and the type of lesion identified (1).

1. Bedi A et al; Clin Sports Med. 2008 Oct;27(4):607-30
2. Myers TH et al; Am J Sports Med. 2005 Sep;33(9):1315-20. Epub 2005 Jul 7.
3. Luime JJ et al; JAMA. 2004 Oct 27;292(16):1989-99
4. Rames RD et al; Orthop Clin North Am. 1993 Jan;24(1):45-53.
5. Stetson WB et al; Am J Sports Med. 2002 Nov-Dec;30(6):806-9.

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