33rd Annual Scientific Meeting proceedings

Objectives
Elbow arthroscopy is frequently used for diagnosis and treatment of elbow dysplasia. After elbow arthroscopy, injection of intraarticular therapeutics is common practice. The question arises, whether the injected therapeutics may effuse in the surrounding soft tissue via iatrogenic injuries from arthroscopy. The goal of the study was to evaluate extravasation of injected contrast-fluid immediately after arthroscopy compared to the contralateral control.

Methods
Sixteen elbows of eight canine cadavers (mean body weight 35kg +/-7,25kg SD) without any radiographic elbow abnormalities were randomly assigned to the arthroscopy-group with the contralateral elbow as control. Immediately after explorative elbow-arthroscopy with a 2,2 mm Nanoscope using standard medial ports (duration: 5-minutes), elbows were injected with 2,5ml contrast-fluid (Iobitridol 300 mg/ml) via the egress-cannula. Contrast-fluid was injected into the contralateral elbow in the same manner. Elbow CT-scans were obtained at seven time points (0, 2, 4, 6, 8, 10, 15 minutes after injection). Volume and intensity of intra- and periarticular contrast-fluid was measured using rendering-software. Statistical analyses were performed to compare volume and intensity of contrast-fluid using a simple linear model and a linear mixed effect model.

Results
Volume of area of contrast-fluid was significantly increased (mean difference of 5115mm3; +/- SE 309 mm3; P<2e-16) and intensity significantly decreased (mean difference of 1330HU; +/- SE 85HU; P<2e-16) in the arthroscopy-group compared to the control. Neither fluid volume nor intensity changed significantly over time.

Conclusion
Significant extravasation of and a distinct dilutional effect on intra-articular injected contrast-fluid was observed in the arthroscopy-group.