Ultrasound-Guided Injection Approach of Treating Tennis Elbow and Elbow Joint Synovitis Simultaneously Under One Needle Insertion Point.

Abstract

A 52-yr-old man with right elbow pain for 6 mos visited an outpatient rehabilitation clinic. An obvious tender spot at the lateral epicondyle area was palpated with positive Cohen test.1 The patient had received autologous platelet-rich plasma injection but without much improvement.2 Musculoskeletal ultrasound images revealed thickening of the common extensor tendon, combined with diffuse heterogeneity and focal hypoechogenicity. Bony irregularity was observed at the tendon insertion site. The diagnosis of lateral epicondylitis, also known as “tennis elbow,” is a common cause of elbow pain. The exact pathogenesis remains elusive and is often difficult to treat. Ultrasound-guided injection to the bone and common extensor tendon interface may not be effective as many patients are also bothered with elbow joint synovitis.3 As a result, this article describes an important ultrasound-guided injection approach to treat tennis elbow and joint synovitis simultaneously under one needle insertion point. When applying ultrasound-guided injection to treat tennis elbow, the elbow is flexed at a 90-degree angle. The ultrasound linear probe is placed over the lateral epicondyle, along the longitudinal axis of the common extensor tendon origin. Under this sonographic view, the common extensor tendon, the lateral epicondyle, and the elbow joint can be observed. Conventionally, injection can be done under the longitudinal view, in a distal-to-proximal or proximal-to-distal direction, by guiding the needle to the bone tendon (extensor carpi radialis brevis tendon) interface.4 For patients who are also bothered with elbow joint synovitis, simultaneous injection to the bone-tendon interface, and aspiration of the joint fluid followed by the injection of an injectant may be needed (Figs. 1A, B).3 However, under the in-plane or longitudinal view, needle insertion into the elbow joint can be difficult because of the convex curvature of the radial head (Fig. 1B). Therefore, a different injection approach is recommended. Similar to the conventional method, the linear probe is placed longitudinally on top of the elbow joint. The needle is then inserted in a lateral-to-medial direction under the out-of-plane approach or short-axis view into the elbow joint (Figs. 2A, B). The needle is observed as a hyperechoic dot inside the elbow joint. Aspiration of the joint fluid followed by injection can then be performed. Still under the short-axis view, the needle is retracted and then guided in a slightly obliqued direction to the bone-tendon interface to commence subsequent injection treatment (Figs. 3A, B). Steroid was the injectant used. Elbow pain was greatly improved after the treatment.FIGURE 1: A, The linear ultrasound transducer is placed longitudinally on top of the right elbow to visualize the lateral epicondyle, common extensor tendon, bone-tendon (extensor carpi radialis brevis) interface, and the elbow joint. Conventionally, injection can be done under the longitudinal view and in a distal-to-proximal direction by guiding the needle to the bone-tendon interface. B, The needle is accurately guided to the bone-tendon (extensor carpi radialis brevis) interface (*). Due to synovitis, increased hypoechogenicity (resembling fluid accumulation) can be observed in the elbow joint (+). Using the distal-to-proximal direction needle approach, insertion into the elbow joint can be difficult because of the convex curvature of the radial head.FIGURE 2: A, With the linear ultrasound transducer placed longitudinally on top of the right elbow, the needle is inserted in a short-axis or out-of-plane view relative to the transducer and guided into the elbow joint (pink area). B, Under the short-axis view, the injection needle can be visualized as a hyperechoic dot inside the elbow joint.FIGURE 3: A, After completing elbow joint injection, the needle is then retracted and the syringe is moved slightly in a distal direction to guide the needle to the lateral epicondylar area (curved white arrow). B, Still under the short-axis view or slightly obliqued short-axis view, the needle is guided to the bone-tendon interface.