Opiate sparing effect of fixed combination of diclophenac and orphenadrine after unilateral total hip arthroplasty: A double-blind, randomized, placebo-controlled, multi-centre clinical trial

Summary Multimodal pain management combines analgesics to improve analgesia and reduce side effects. This study investigates the fixed combination of diclophenac and orphenadrin (Neodolpasse ® Infusion Solution) in patients after unilateral total hip arthroplasty (THA). This prospective, randomized, double-blind, placebo-controlled, multi-centre clinical study enrolled 120 patients receiving patient-controlled analgesia (PCA). Isotonic saline was infused as placebo. The primary efficacy goal was defined as reduction of PCA analgesics used over the first 24 h post-surgery. The study used a three-stage group sequential test design with two interim analyses. Analgesia was monitored by visual analogue scale and verbal rating. Infusion of the Neodolpasse ® Infusion Solution resulted in a significant reduction in the PCA analgesic requirements by approximately 30% (38.7 ± 21.3 mg vs. 55.9 ± 31.1 mg; p = 0.0004) while maintaining adequate analgesia and patient safety. This study demonstrates that Neodolpasse ® Infusion Solution significantly reduces PCA analgesic requirements without compromising analgesic effectiveness and safety in THA patients.