# Extravasation of Intraarticular Fluid Injection Following Canine Elbow Arthroscopy: A Cadaveric Study

## TL;DR

This study used CT scans to examine how contrast fluid spreads after elbow arthroscopy in dogs, finding that fluid leaks out but not significantly over time.

## Contribution

The study provides new insights into contrast fluid extravasation after canine elbow arthroscopy using a cadaveric model and CT imaging.

## Key findings

- Contrast fluid volume increased in the arthroscopy group compared to the control.
- Contrast fluid intensity decreased in the arthroscopy group compared to the control.
- Extravasation occurred but did not significantly change over 15 minutes.

## Abstract

To investigate extravasation of contrast media injected intraarticularly, either immediately following elbow arthroscopy or after arthrocentesis using computed tomographic (CT) imaging at different time points.

Cadaveric dog model.

A total of 16 elbows of eight canine cadavers (median age 10.2 years, 5.6 to 16.8 years; median weight 35.0 kg, 26.0 to 42.0 kg) were randomly assigned to the arthroscopy group with the contralateral elbow as control. Right after elbow arthroscopy, both elbows were injected with 2.5 mL contrast fluid. Elbow CT scans were obtained at seven time points. To detect a possible loss of contrast medium from the joint, both the total volume and intensity of the contrast fluid were measured intra- and extraarticularly using rendering software. To compare volume and intensity of contrast fluid, a simple linear model and a linear mixed effect model were used.

The total volume of contrast-enhanced fluid was increased (avg. difference: 5115 mm
3
; linear model std. estimate: 1.69, std. error 0.10) and the total intensity decreased (avg. difference: 1330 Hounsfield Units; linear model std. estimate: −1.66, std. error 0.11) in the arthroscopy group compared with the control. Neither total volume nor total intensity of contrast-enhanced fluid changed significantly within 15 minutes.

Extravasation of intraarticular injected contrast fluid after elbow arthroscopy without a significant effect of time could be shown. Injection of liquid therapeutics, e.g., orthobiologics, at a later point after arthroscopy should be considered.