Accuracy of ultrasound-guided versus palpation-based carpometacarpal joint injections: A randomized pilot study in cadavers

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.