The spread of Injectate after ultrasound-guided lateral elbow injection \u2013 a cadaveric study

Jonathan P Evans,William J Thomas,Andrew King,Jeremy Metz,Chris D Smith,Vicki A Goodwin,Rahul Anaspure

doi:10.1186/s40634-018-0142-8

Abstract

BackgroundInjections into the tendinous portion of the common extensor origin are a common intervention in the treatment of Lateral Elbow Tendinopathy (LET). Clinical trials report a heterogeneous selection of injectate volumes and delivery techniques, with systematic reviews finding no clear consensus. The aim of this study was to assess the intratendinous distribution and surrounding tissue contamination of ultrasound-guided injections into the Common Extensor Tendon (CET) of the elbow.MethodsTwenty cadaveric elbows were injected by a Consultant Radiologist under Ultrasound guidance. Elbows were randomised to equal groups of 1 or 3 mls of methylene blue injection, delivered using single shot or fenestrated techniques. Following injection, each cadaver underwent a dry arthroscopy and dissection of superficial tissues. The CET was excised, set and divided into 1 mm sections using microtome. Each slice was photographed and analysed to assess spread and pixel density of injectate in four colour graduations. The cross-sectional area of distribution was calculated and compared between groups.ResultsIn all 20 cadaveric samples, contamination of the joint was noted on arthroscopy and dissection. Injectate spread through over 97% of the cross-sectional area. No differences were found in intratendinous spread of injectate between differing volumes or techniques.ConclusionThis study found that commonly used injection volumes and techniques distribute widely throughout cadaveric CETs. There was no improvement when the volume was increased from 1 to 3 mls or between single shot of fenestrated injection techniques. It should be noted that joint contamination using these techniques and volumes may be inevitable.

Highlights

Injections into the tendinous portion of the common extensor origin are a common intervention in the treatment of Lateral Elbow Tendinopathy (LET)
Pre-injection ultrasound identified that 60% of the 20 cadavers had Common Extensor Tendon (CET) tears, 33% of those tears were located at the footprint and an average size on ultrasound measurement of 5.8 mm (Range 6-8 mm)
Intra-articular elbow joint contamination was evident in all 20 specimens on dry arthroscopy

Summary

Introduction

Injections into the tendinous portion of the common extensor origin are a common intervention in the treatment of Lateral Elbow Tendinopathy (LET). Injection therapy for chronic lateral elbow tendinopathy (LET), known commonly as tennis elbow, remains a popular treatment choice (Sahbudin & Peall, 2013; Titchener et al, 2015). Pathological change in LET occurs within the proximal tendons of the common wrist extensor muscles, with particular reference to the extensor carpi radialis brevis (ECRB). This is the intended site of injection therapy in LET. The ECRB tendon originates from the lateral epicondyle, lying deep to the remaining common extensor tendons and superficial to the thin articular capsule of the elbow (Nimura et al, 2014). Injection volumes delivered to this area commonly range from 0.5–

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