Is a Steroid Injection in Both Compartments More Effective than an Injection in the Extensor Pollicis Brevis...

Ultrasonography (US)-guided steroid injections can improve the accuracy of injection in patients with de Quervain disease, especially in those with an intracompartmental septum. Although the main lesion of de Quervain disease in patients with a septum is a stenosing tenosynovitis of the extensor pollicis brevis (EPB), no report we know of has compared injection into the EPB subcompartment with an injection into both the abductor pollicis longus (APL) and EPB subcompartments. In this randomized trial, we compared the results of US-guided steroid injections targeting both subcompartments and the EPB subcompartment alone in patients with de Quervain disease.

(1) Do patients who receive a steroid injection in the EPB subcompartment alone have lower pain scores at 6 weeks and at 3 months after US-guided injection compared with patients who receive an injection in both subcompartments? (2) Do patients who receive a steroid injection in the EPB subcompartment alone experience fewer steroid injection-related complications than patients who receive an injection in both subcompartments?

A randomized controlled study was performed at a single center between August 2018 and March 2021. Patients with a diagnosis of de Quervain disease and with a complete intracompartmental septum between the APL and the EPB tendons were included. In total, 112 patients had a diagnosis of de Quervain disease during the study period. Definite, complete subcompartmentalization was seen in 50 patients. Patients were randomly assigned to US-guided injections targeting both subcompartments (n = 25) or the EPB subcompartment alone (n = 25). There were no between-group differences in age, gender, affected wrist, or disease duration, and all patients had US evidence of tendinosis of the EPB, with or without tendinosis of the APL. Although 33% of patients (16 of 48) showed tendinosis of the APL, no patient showed tendinosis of the APL alone. In all patients, a dorsal-to-palmar side injection of 0.5 mL of 2% lidocaine and 0.5 mL of triamcinolone acetonide (40 mg/mL) was administered by two experienced hand surgeons. In the both-subcompartments group, US-guided injections were performed in each of the APL and EPB subcompartments. In the EPB subcompartment group, US-guided injections were administered in the EPB subcompartment only. All patients underwent the same protocol after the procedure. Four percent (n = 2, 1 in each group) of patients were excluded after randomization because their pain level was not registered. Pre- and postinjection clinical outcome assessments were completed by orthopaedic surgery residents not involved in patient management. Patients were regularly examined at baseline, 6 weeks, and 3 months to evaluate the intensity of pain. We assessed pain by the VAS score, where 0 indicated no pain and 100 the most pain. At baseline, the VAS score was 67 ± 14 in the both-subcompartment group and 67 ± 16 in the EPB subcompartment group (mean difference 0.17 [95% CI -8.45 to 8.82]; p = 0.97). Complications related to the steroid injection, including numbness, tendon rupture, and skin hypopigmentation, were also recorded at final follow-up examinations. To determine statistical power, the VAS score for pain at 6 weeks after the injection was used as the primary outcome variable. The minimum clinically important difference for the VAS score was deemed to be 20 mm, and we estimated an SD of 23. A sample size calculation indicated that a sample of 21 patients per group would provide 80% power to detect an effect of this size between the groups at the p = 0.05 level using a t-test.

There were no differences in the VAS scores between the both-subcompartment group and the EPB group at 6 weeks (10 ± 6 versus 10 ± 7, mean difference -0.08 [95% CI -4.08 to 3.91]; p = 0.97). The same was true at 12 weeks (12 ± 13 versus 11 ± 15, mean difference 0.38 [95% CI -7.74 to 8.49]; p = 0.09). No adverse events related to treatment (such as tendon rupture, infections, and numbness) occurred in either group. However, skin hypopigmentation occurred at the final follow-up examination in both groups. The proportion of patients experiencing skin hypopigmentation in the EPB subcompartment group was lower than in the both-subcompartment group (33% [8 of 24] versus 67% [16 of 24]; odds ratio 0.25 [95% CI 0.08 to 0.83]; p = 0.02).

Our data suggest that a US-guided steroid injection targeting the EPB subcompartment alone is as effective in terms of pain reduction as targeting both subcompartments in patients with de Quervain disease who have complete septation. Furthermore, an injection targeting the EPB subcompartment alone can reduce the dose of steroids used, perhaps thereby decreasing complications related to steroid injections. We recommend using only single-compartment injections in this context, even among patients with an intracompartmental septum.

Level I, therapeutic study.