Contrast-enhanced ultrasonographic visualisation of intra-synovial injections

Ever so often you run across an idea that is so simple you have to wonder why you never thought of it yourself. So it is with this one. Simply shaking the solution you are about to inject in a joint makes confirming the accuracy of placement of your medication as simple as a ultrasound exam. Though many of the intraarticular injections are easily learned there are some joints that even specialist have trouble reliably injecting. Here we have a easy noninvasive method to test the results.
DrO

Contrast-enhanced ultrasonographic visualisation of intra-synovial air bubbles following injection with an agitated solution in horses
Equine Vet J. 2020 Nov 21.
Authors
N K E Ogden 1 , M D Cullen 1 , J D Stack 1
Affiliation

1 Leahurst Equine Hospital, Faculty of Veterinary Science, University of Liverpool, Neston Cheshire, CH64 7TE, UK.

Abstract

Background: Accuracy of intra-synovial injections can be challenging to assess in a clinical setting in horses. Contrast-enhanced ultrasonography (CEUS) using injectate agitated with air has been utilised to determine the success rates of synovial injections in human rheumatology.

Objectives: To assess the diagnostic sensitivity and specificity of CEUS and to describe its clinical use.

Study designs: Cadaveric study followed by a prospective descriptive observational study.

Methods: Part 1: Contrast-enhanced ultrasonography was performed following injection of agitated methylene-blue solution targeting thirteen different anatomical synovial structures from three equine cadavers. Contrast was seen as hyperechoic dots, patches or lines on ultrasonography. Contrast-enhanced ultrasonography was classified as positive if contrast was considered to be intra-synovial and negative if contrast was considered to be extra-synovial. A second synoviocentesis was performed to determine if the injection was intra-synovial based on the presence or absence of methylene-blue. Estimates of sensitivity and specificity were calculated. Part 2: Contrast-enhanced ultrasonography was performed following injection of agitated solutions targeting synovial structures as part of routine investigation and treatment of clinical cases.

Results: Part 1: Contrast-enhanced ultrasonography was correctly classified as positive or negative in all intra-synovial and extra-synovial injections respectively. The sensitivity estimate was 100% (CI 93-100%) and the specificity estimates was 100% (CI 16-100%). Part 2: The technique was used safely for 26 injections (14 horses; 19 different synovial structures) administered to localise or treat lameness. Traumatic inter-synovial communications or synovial membrane defects were identified using CEUS in three horses.

Main limitations: The low number of extra-synovial injections in Part 1 resulted in an imprecise specificity estimate.

Conclusions: In horses CEUS performed following intended intra-synovial injection can be useful for identifying unsuccessful injections.