Among the types of glenoid labral tear, it has been shown that the posterosuperior (PS) labral tear can occur in both athletes and nonathletes using overhead throwing motion with PS impingement or having repetitive shearing of the humeral head against the PS labrum.1 For the definite diagnosis of PS labral tear, arthroscopy, arthrography, or magnetic resonance imaging are usually required. However, in recent studies, the ultrasound (US) arthrosonography has been reported as one of the useful methods to diagnose PS labral tear.2,3
In addition to conventional US scanning of shoulder labrum, we propose a novel method for dynamic evaluation of the PS labral tear. When examining the PS labrum with US, a high-frequency (5–12 MHz) linear probe is used, with the patient sitting down in front of the examiner. First, the conventional US scanning of PS labrum, with the patient's arm passively adducted and internally rotated with the elbow flexion of 90 degrees, is done. Then, a dynamic examination is performed by the examiner passively abducting and externally rotating the arm. The humeral head is rotated externally when the arm is passively abducted and external rotated, which gives stress to the PS labrum (abduction and external rotation [ABER] stress test). In a normal PS labrum, there would not be any significant finding (Fig. 1). However, in injured PS labrum, this stress may cause posterior and medial detachment of the labrum or joint fluid leakage through the torn PS labrum (Fig. 2). The dynamic imaging is also presented in the attached video (Videos 1, 2).
This Video 2 demonstrates a 36-yr-old, left-handed man, with recent right shoulder pain. The subject complained of posterior shoulder pain with a clicking sensation when ABER stress test was performed. He is a physiatrist, and the pain started right after he gave his teammate a high five during a basketball game. The initial level of pain at the posterolateral shoulder was rated 7 of 10 on a numeric rating scale during ABER maneuver. There was no loss of passive motion of the shoulder joint, but there were posterior joint-line tenderness and pain at the end range of external rotation at 90-degree abduction. The O'Brien test was positive. A PS pain was induced by posterior apprehension test and relieved by relocation test. However, other tests, such as Hawkins-Kennedy's test, Neer test, Yegason's test, and adduction stress test, were negative. Ultrasound examinations were performed by a physiatrist with more than 5 yrs of experience in musculoskeletal US. After the diagnosis of PS labral tear by ultrasonography, he then underwent US-guided glenohumeral joint steroid injection (triamcinolone 20 mg + normal saline 7 ml + 1% lidocaine 7.5 ml, total 15 ml).2,3 After the injection, he was educated on adequate posture and exercise; he was advised to avoid excessive abduction and external rotation of the shoulder and to start scapular stabilization exercises. One week after the injection, he reported significant pain relief. The pain intensity dropped from 7 to 1, in a numeric rating scale. He was pain free during daily activities as long as excessive shoulder movement was avoided.
1. Budoff JE, Nirschl RP, Ilahi OA, et al: Internal impingement in the etiology of rotator cuff tendinosis revisited. Arthroscopy
2. Park D: Clinical characteristics of patients with posterosuperior labral tear: a comparison with patients with other shoulder disorders. J Pain Res
3. Park D: Evaluation of posterosuperior labral tear with shoulder sonography after intra-articular injection: a case series. Am J Phys Med Rehabil