A 40-yr-old woman had contusion on her left shoulder in a traffic accident 2 wks before clinical examination at our department. Afterward, she could not raise her left arm because of severe pain. Plain radiographs were negative and medical treatment with a nonsteroidal anti-inflammatory drug had been ineffective. Application of hot packs and interferential current therapy resulted in limited pain relief. She was referred for an ultrasound (US) examination for a rotator cuff tendon tear. Prescanning physical findings showed tenderness over the coracoid process, limited range of shoulder abduction, and flexion. The painful arc, Hawkins-Kennedy, and Neer tests were positive. Ultrasound imaging of the supraspinatus tendon disclosed a small partial tear. Herewith, because her symptom severity was not consistent with the US finding, we further assessed the superior labrum concerning her trauma history. Using a curvilinear transducer in the oblique coronal plane,1 we identified a hypoechoic slip inside the hyperechoic triangular labrum. The proximal portion of the biceps tendon (long head) appeared intact. With forcefully pulling the arm downward, the slip was enlarged with fluid filling the gap. Keeping the arm in abduction, a dynamic examination was conducted by pronation, supination, and forceful traction of the forearm1 (Figs. 1A, B, Video 1). The diagnosis of superior labrum anterior to posterior (SLAP) lesion was also confirmed with magnetic resonance imaging (Figs. 1C, D). Under US guidance, a single injection of 10 ml of 15% dextrose was applied to the lesion in an attempt to cover the superior labrum and proximal biceps tendon. Her symptoms gradually improved.
The SLAP lesion is a tear of the superior labrum near the attachment of the long head of the biceps tendon. It is not rare in athletes with frequent overhead throwing activities and is occasionally caused by direct contusion on shoulders during abduction and external rotation. Anterior shoulder pain and multidirectional instability are the common chief complaints. Hawkins, Neer, and Speed tests may be sensitive, but not specific for SLAP lesions.2,3 For its diagnosis, magnetic resonance arthrography—detecting the clefts in the labrum or between the labrum and the glenoid—is the criterion standard.4 Until now, there are few articles addressing the diagnosis of SLAP lesions by using US. Because the physicians commonly use a linear transducer to scan the shoulders, US imaging might yield limited penetration and resolution for deeper structures. In addition, visualization of the labrum requires specific positioning of the patient with shoulder abduction and external rotation. To parallel the orientation of the long head of the biceps tendon, the probe is placed between the coracoid process and acromioclavicular joint. Otherwise, the labrum will be hindered under the coracoid process. In our case, we chose the curvilinear probe for its better penetration. Furthermore, the radiation pattern of the US beam permits us to visualize the structure under the coracoid process. Last but not least, with dynamic US imaging while pulling the affected shoulder downward to enlarge the slip,1 architecture of the labrum, biceps tendon origin, and hypoechoic foci in the hyperechoic labrum can easily be defined.
In short, showing its applicability for SLAP lesions, we imply that US imaging of the superior labrum needs to be performed in patients with shoulder trauma.
1. Hsiao M-Y, Hung C-Y, Chang K-V, et al: Dynamic ultrasonography of the intra-articular long head biceps tendon and superior labrum. Am J Phys Med Rehabil
2. Myers TH, Zemanovic JR, Andrews JR: The resisted supination external rotation test: a new test for the diagnosis of superior labral anterior posterior lesions. Am J Sports Med
3. Sodha S, Srikumaran U, Choi K, et al: Clinical assessment of the dynamic labral shear test for superior labrum anterior and posterior lesions. Am J Sports Med
4. Holzapfel K, Waldt S, Bruegel M, et al: Inter- and intraobserver variability of MR arthrography in the detection and classification of superior labral anterior posterior (SLAP) lesions: evaluation in 78 cases with arthroscopic correlation. Eur Radiol