Hip aspiration: A comparison of ultrasound and fluoroscopic guidance

Hip aspirations are commonly performed for diagnostic purposes using either fluoroscopic or ultrasound guidance. The superiority of one type of image guidance over another for aspiration of a native or replaced hip remains a matter of debate. The questions to be evaluated in this study include 1) to determine if hip aspiration using fluoroscopy or ultrasound guidance more often obtains fluid from native and post-arthroplasty hip joints, and 2) to identify patient-related factors associated with the ability to obtain fluid.

A retrospective analysis of all hip aspirations (433) performed at a single institution was undertaken, with the primary outcome variable being successful attainment of joint fluid. Age, body mass index (BMI), sex, presence of a trainee, presence of an arthroplasty at the time of aspiration on the affected side, amount of fluid collected, and type of image guidance were used as independent variables in regression models.

1) The likelihood of obtaining fluid was approximately 2.1 times greater with ultrasound guidance than fluoroscopy guidance (95% CI = 1.382, 3.117; p < 0.001). 2) Ultrasound guidance and lower BMI were independently associated with a significantly higher likelihood of obtaining fluid. Additionally, one unit decrease in BMI was associated with about a 3% increase in the odds of obtaining fluid (95% CI = 0.950, 0.998; p = 0.033).

This study demonstrates that the use of ultrasound guidance for hip joint aspiration, when compared to fluoroscopic guidance, is more likely to result in a successful aspiration and the acquisition of a greater volume of fluid. Therefore, ultrasound guidance is the preferred method for hip aspiration in both native and replaced hips.