Accuracy of Wireless Hand-Held Guided Ultrasound Injections in the Trapeziometacarpal Joint: A Cadaveric Study

Background Symptomatic trapeziometacarpal osteoarthrosis can be treated with an ultrasound-guided injection in the early stages. This cadaveric study aimed to assess the hypothesis suggesting enhanced accuracy and reliability of hand-held ultrasound (HHUS) injections compared to blind injections into the trapeziometacarpal joint (TMC). Materials and method Our series included 20 fresh cadaveric hands, with a total of 20 TMC randomly assigned to two groups. In group A, 10 TMC received a blinded injection, and in group B, 10 TMC received an ultrasound-guided injection with HHUS. Methylene blue was injected, and anatomical dissection was performed to assess the intra-articular location of the dye. The injection was considered accurate if the intra-articular synovial fluid was stained after opening the articular capsule on the dorsal approach. If there was no injection, it was inaccurate. A statistical analysis was performed, and p <.05 indicated a significant difference. Results Two thumbs were excluded during the study due to an existing trapeziectomy. In group A, 10 blind injections of TMC were performed, with 70% (7/10) of injections graded as accurate. In group B, eight ultrasound-guided injections were performed, with 75% (6/8) achieving accuracy. A Fisher's exact test was performed, and the results indicated no statistically significant difference in injection accuracy between the two groups (P = 1, odds ratio = 0.788). Conclusion Hand-held ultrasound guided TMC injections were not more accurate than blind injections performed by an experienced hand surgeon. Nonetheless, additional studies with a larger sample and comparative studies with conventional cart-based machines are necessary to evaluate the potential of this newly accessible device.