Accuracy of sonographically guided and palpation guided scaphotrapeziotrapezoid joint injections

Objectives - The purpose of this study was to determine and compare the accuracies of sonographically guided and palpation guided scaphotrapeziotrapezoid (STT) joint injections in a cadaveric model. Methods - A clinician with 6 years of experience performing sonographically guided procedures injected 1.0 mL of a diluted latex solution into the STT joints of 20 unembalmed cadaveric wrist specimens using a palmar approach. At a minimum of 24 hours after injection, an experienced clinician specializing in hand care completed palpation guided injections in the same specimens using a dorsal approach and 1 mL of a different- colored latex. A fellowship-trained hand surgeon blinded to the injection technique then dissected each specimen to assess injection accuracy. Injections were graded as accurate if the colored latex was found in the STT joint, whereas inaccurate injections resulted in no latex being found in the joint. Results - All sonographically guided injections were accurate (100%; 95% confidence interval, 81%-100%), whereas only 80% of palpation guided injections were accurate (95% confidence interval, 61%-99%). Sonographically guided injections were significantly more accurate than palpation guided injections, as determined by the ability to deliver latex into the joint (P < .05). Conclusions - Sonographic guidance can be used to inject the STT joint with a high degree of accuracy and is more accurate than palpation guidance within the limits of this study design. Clinicians should consider using sonographic guidance to perform STT joint injections when precise intra-articular placement is desired. Further clinical investigation examining the role of sonographically guided STT joint injections in the treatment of patients with radial wrist pain syndromes is warranted.