Ultrasound Imaging for Lateral Elbow Pain: Pinpointing the Epicondylosis.

Abstract

HISTORY AND PHYSICAL EXAMINATION A 40-yr-old woman presented with a 2-mo history of atraumatic, right-sided, 7/10 constant, achy lateral elbow pain, and functional limitations in daily activities (eg, typing on a keyboard at work). Physical examination revealed pain at the lateral epicondyle, which also limited active range of motion and resisted wrist extension and ulnar deviation. The differential includes tendinopathy of the common extensor tendon (CET), supinator or radial tunnel syndrome (with posterior interosseous nerve entrapment), osteochondral defect, osteoarthritis, and cervical spine radiculopathy. IMAGING Ultrasound examination was performed in accordance with the European Musculoskeletal Ultrasound Study Group/Ultrasound Study Group della International Society of Physical and Rehabilitation Medicine scanning protocols1 using a high-frequency linear probe (4–16, Sonoscape X3). A bone spur of the lateral epicondyle and a small persistent hypoechoic area consistent with focal insertional tendinosis of the CET was seen in the longitudinal view (Fig. 1A). A transverse view of the lateral epicondyle2 was also performed (Fig. 1B), which confirmed previous findings and showed a peripheral tear of the extensor carpi ulnaris tendon (Fig. 1C).FIGURE 1: Ultrasound image in the long-axis view shows the bony spur (white arrow) on the lateral epicondyle and a small hypoechoic area (asterisk) compatible with focal insertional tendinosis of the CET (specifically EDc and EDm) (A). Positions of the probe in the long-axis (black rectangle) and short-axis (black dotted rectangle) planes at the lateral epicondyle of the right elbow (B). Ultrasound image in the axial view shows the bony spur (white arrow), focal insertional tendinosis of the CET (asterisks) at the level of EDc and EDm tendons, and the focal tear of the extensor carpi ulnaris tendon (white arrowhead) (C). Schematic drawing shows the focal tear of the extensor carpi ulnaris tendon in the peripheral portion of the CET in the transverse view (D). E, epicondyle; ECUECU, extensor carpi ulnaris; EDc, extensor digitorium communis; EDm, extensor digiti minimi; ERCB, extensor carpi radialis brevis; ERCL, extensor carpi radialis longus; F, subcutaneous fat tissue; R, radius.TREATMENT AND OUTCOME Based on the sonographic findings, stretching of the extensor carpi ulnaris was initially avoided for 10 days to prevent worsening of tearing. After 1 wk of static stretching followed by 3 wks of stretching and eccentric exercises,3 the patient reported significant pain relief with return to normal active range of motion and strength. DISCUSSION/CONCLUSIONS The CET tendinopathy is usually diagnosed clinically, but diagnostic imaging with point-of care sonographic evaluation offers a high-resolution, low-cost imaging modality that allows for dynamic examination and side-to-side comparison that can guide rehabilitation treatment.4 Knowing exactly which tendon is involved can help one determine what exercises to do or avoid. For example, if the extensor carpi radialis and extensor digitorium are tendinopathic, targeting wrist extension, radial deviation, and finger extension is important. In contrast, when extensor carpi ulnaris is involved, finger extension with therapy may be less beneficial. Being able to visualize tears rather than tendinopathy can be important also in avoiding certain movements. Despite that it plays a key role in active movements and dynamic stability of the wrist, the extensor carpi ulnaris tendon is often overlooked because it is not commonly affected; however, it may be a key contributor to a patient's discomfort.5 This case displays the utility of ultrasound imaging of the lateral epicondyle to identify the exact anatomical location of the pain generator and allow the physiatrist to plan a tailored rehabilitation program. Learning Points - Lateral epicondylosis is commonly encountered in physiatry practice and sonographic imaging is a valuable, first-line diagnostic tool to correctly identify the pain generator. - A more specific diagnosis for lateral elbow pain guides a tailored rehabilitation program that theoretically leads to faster functional recovery than if the rehabilitation program is not tailored to the exact pathology.