(O-H4) Ultrasound vs Landmark Guided Small and Medium Joint Arthrocentesis: A Randomized Control Trial

Objectives: The objective of this study is to compare ultrasound guided (USG) and landmark guided (LMG) medium joint arthrocentesis by emergency medicine residents with respect to success rate and attempts.

Background: Arthrocentesis is a basic emergency medicine skill, but it is not without complications. Presently, there is a paucity of data assessing the utility of ultrasound guided medium joint arthrocentesis. A few small cadaveric studies suggest it improves the rate of success and time to successful aspiration, while reducing number of attempts.

Methods: This was a single-center, prospective, randomized clinical trial (NCT03327584) of a convenience sample of adult patients who presented to an urban, university hospital with > 105,000 visits annually. Patients with a suspected medium-sized joint effusion (defined as elbow, wrist, or ankle) undergoing arthrocentesis were randomized into LMG or USG using the GE Logiq e linear transducer (4–10 MHz). The following patients were excluded: on anticoagulation, with soft tissue infection overlying the joint, or involving an artificial joint. The sample size calculation of 28 was based on a power of 80% with an estimated difference of successful aspiration of 45% between techniques based on previous literature. Statistical analyses included the Fisher exact, Mann-Whitney U-test, and t-test.

Results: Overall, 44 patients were enrolled with 23 patients randomized into the LMG group and 21 patients into the USG arm. USG was significantly better than LMG with an overall success of 94.1% versus 60% for LMG (difference = 34.1%, 95% confidence interval [CI] = 4.90 to 58.83). USG first-pass success was 82.4% versus 46.7% for LMG (difference = 35.7%, 95% CI = 2.76 to 60.37) and a mean of 1.35 attempts versus 2.00 for LMG (difference = 0.65, 95% CI = 0.005 to 1.296). Of the 14 LMG failures, eight had no effusion present on USG crossover. Four patients in the USG group had no effusion present.

Conclusions: Ultrasound guidance improved first-pass and overall successful arthrocentesis of medium-sized joint effusions.

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Funding (Optional): none