Article

The aim of this study was to identify the detectable threshold of knee
effusion by ultrasonography while infusing saline.
DESIGN: Forty knee
osteoarthritis patients were allocated randomly to either the midline or the
lateral group. Intra-articular injection of 20 ml normal saline was performed
under ultrasonographic guidance with the transducer fixated at the midline
longitudinal or lateral longitudinal scan in the midline and lateral groups,
respectively. We obtained ultrasonography images after infusing each milliliter
and measured the maximum depth of effusion. RESULTS: The smallest amount of
infusion detected by ultrasonography was 4.37 +/- 2.11 ml in the midline group
and 4.13 +/- 1.71 ml in the lateral group. An effusion more than 2 mm deep was
observed after infusing 7.84 +/- 3.85 ml and 7.38 +/- 3.01 ml in the midline and
lateral groups, respectively. To obtain a 4-mm depth, infusions of 11.58 +/- 5.68
ml and 13.13 +/- 4.88 ml were needed in the midline and lateral groups,
respectively. CONCLUSIONS: To detect knee effusion by ultrasonography, infusion
of 4.26 ml (SD, 1.92 ml) of solution is needed. We think that a depth of 2 mm is
more appropriate than 4 mm as the definition of knee effusion using
ultrasonography.

Langue : ANGLAIS