A Randomized Controlled Trial Comparing Single-Injection versus Continuous Brachial Plexus Block for Postoperative Pain Control after Open Reduction and Internal Fixation of Distal Radius Fractures

PURPOSE: Successful treatment of distal radius fractures involves stable anatomic reduction, postoperative pain control, and rehabilitation. We hypothesized that patients treated with a continuous brachial plexus block (cPNB) would have less postoperative narcotic use and better postoperative pain control than patients treated with a single-injection block (siPNB). METHODS: Adult patients with distal radius fractures scheduled to undergo volar plate fixation were eligible for enrollment in an IRB-approved single-blinded randomized clinical trial beginning in 2018. All patients consented to the treatment plan and were randomized into either the siPNB or cPNB group. All blocks were performed preoperatively by the same team. Operations were performed by one of two fellowship-trained hand surgeons, and the postoperative pain treatment regimen was standardized. Patients were contacted by phone at each of the following time points: eight hours after surgery and on postoperative days 1-5. Pills taken and visual analogue scale (VAS) pain scores were assessed at each time point. Functional assessments at postoperative follow-up visits included 2-point discrimination, grip strength, and wrist range of motion. Patient-reported outcome measures (PROMs) included the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire; Patient Rated Wrist Evaluation (PRWE); and Boston Carpal Tunnel Questionnaire (BCTQ) scores. Single comparisons for continuous variables were tested using unpaired t-tests. Data collected were compared between the two groups and a p-value <0.05 was considered significant. RESULTS: There were 22 patients enrolled in the siPNB group and 17 patients enrolled in the cPNB group. Both groups were predominately composed of female patients (86% siPNB vs. 65% cPNB, p=0.11) of similar ages (54±15 siPNB vs. 49±15 cPNB, p=0.29). Total operative time did not differ significantly between treatment groups (100±21 siPNB, vs. 95±22 cPNB). Opioid utilization and VAS pain scores were not significantly different among the two groups at any time point. Functional outcomes evaluated 98±57 days postoperatively were also comparable between the two groups: two-point discrimination (6±1mm siPNB vs. 7±¬1mm cPNB, p=0.21), and grip strength (16±8 kg siPNB vs. 20±9 kg cPNB, p=0.24). Wrist range of motion (ROM) did not reveal any significant differences between groups in flexion (46±13º siPNB vs. 45±16º cPNB, p=0.74), extension (56±14º siPNB vs. 49±20º cPNB, p=0.26), radial deviation (18±7º siPNB vs. 17±6º cPNB, p=0.57), nor ulnar deviation (20±10º siPNB vs. 25±7º cPNB, p=0.28). Patients from each group also scored similarly on patient-reported outcome measures (PROMs): DASH (15±26 siPNB vs. 16±16 cPNB, p=0.93), DASH Work Module (11±28 siPNB vs. 28±40 cPNB, p=0.59), PRWE Pain (13±13 siPNB vs. 12±4 cPNB, p=0.98), PRWE Function (8±16 siPNB vs. 10±16 cPNB, p=0.91), PRWE Total (23±32 siPNB vs. 23±16 cPNB, p=0.98), BCTQ Symptom Severity (1±1 siPNB vs. 2±1 cPNB, p=0.24), and BCTQ Functional Status (2±1 siPNB vs. 2±1 cPNB, p=0.90). CONCLUSION: Patients receiving continuous brachial plexus block (cPNB) reported similar opioid use and pain scores when compared to patients who received a single-injection block (siPNB). Both groups also had similar functional outcomes, PROM scores, and excellent pain control, suggesting that both anesthetic methods remain viable options for open reduction and internal fixation of distal radius fractures.