Abstract
Objective
To determine the accuracy of ultrasound guidance compared to palpation in performing carpometacarpal joint injections in cadavers.
Design
In all, 36 carpometacarpal joints were randomized to either ultrasound-guided or palpation-based injections, with 1 cc of blue latex solution injected into each joint. The specimens were then dissected and the distribution of the latex was assessed by two independent, blinded raters. Injection accuracy was evaluated on a four-point quartile rating scale of 1–4, corresponding to the amount of the latex solution within the joint (1 = 0–25%, 2 = 26–50%, 3 = 51–75%, 4 = 76–100%). Inter-rater reliability was a secondary measure.
Results
The mean rating of accuracy was 2.1 for both palpation-based and ultrasound-guided injections. There was no statistically significant difference in accuracy between the two injectors. Chi-square analysis testing differences in accuracy for the two conditions was not statistically significant. The Cronbach’s alpha for rater 2 was 0.74, which represents an acceptable level of reliability. A Friedman’s Chi-square for the two raters was 2.3 (p = 0.13), indicating no significant difference between raters.
Conclusion
Ultrasound guidance did not improve the accuracy of carpometacarpal joint injections in cadavers. However, the high inter-rater reliability attests to the value of the novel assessment scale.
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