Assessing Injection Techniques in the Treatment of Trigger Finger

Background: Trigger finger is characterized by the inability to smoothly flex and extend the digit. Corticosteroids are an accepted non-surgical treatment option and can be delivered via two techniques. While the palmar approach is more commonly used, some have suggested that the mid-axial approach may be less painful for patients and yield higher intrasheath injection rates. The purpose of this study is to compare the accuracy of the palmar and midaxial approaches for delivery of corticosteroids into the flexor tendon sheath using radio-opaque dye in a cadaver model. Methods: A total of 50 injections were performed, 25 via midaxial technique and 25 via palmar technique. A one inch, 25-gauge needle was used to inject 1 mL of Isovue contrast dye into the flexor tendon sheath under live fluoroscopy. The fluoroscopic images were examined after injection to determine intrasheath versus extrasheath delivery of the dye, with visualization of contrast filling the sheath defining a successful injection. Results: The midaxial approach had a success rate of 52% compared to the conventional palmar approach success rate of 36%, p = 0.5. The ring finger is the most common location of trigger finger and the rates of success were equal between groups for this digit (80%). Conclusions: Based on our findings, there is no statistical difference in the accuracy of intrasheath injection between the midaxial technique and palmar technique. The midaxial technique can be considered as an alternative to the palmar technique for trigger finger injection.