Biodegradable nanofiber-membrane for sustainable release of lidocaine at the femoral fracture site as a periosteal block: In vitro and in vivo studies in a rabbit model

The aim of this study was to evaluate the efficacy of a biodegradable, lidocaine-embedded, nanofibrous membrane for the sustainable analgesic release onto fragments of a segmental femoral fracture site. Membranes of three different lidocaine concentrations (10%, 30%, and 50%) were produced via an electrospinning technique. In vitro lidocaine release was assessed by high-performance liquid chromatography. A femoral segmental fracture, with intramedullary Kirschner-wire fixation and polycaprolactone stent enveloping the fracture site, was set-up in a rabbit model for in vivo assessment of post-operative recovery of activity. Eighteen rabbits were randomly assigned to three groups (six rabbits per group): group A comprised of rabbits with femoral fractures and underwent fixation; group B comprised of a comparable fracture model to that of group A with the implantation of lidocaine-loaded nanofibers; and group C, the control group, received only anesthesia. The following variables were measured: change in body weight, food and water intake before and after surgery, and total activity count post-surgery. All membranes eluted effective levels of lidocaine for more than 3 weeks post-surgery. Rabbits in group B showed faster recovery of activity post-operatively, compared with those in group A, which confirmed the pain relief efficacy of the lidocaine-embedded nanofibers. Nanofibers with sustainable lidocaine release have adequate efficacy and durability for pain relief in rabbits with segmental long bone fractures.