Computer-Assisted Instrument Guidance to Improve Adductor Canal Block Performance for Total Knee Arthroplasty: A Pilot Randomized Controlled Trial.

Background Postoperative pain associated with total knee arthroplasties (TKAs) is routinely managed with ultrasound-guided adductor canal blocks (ACBs). Computer-assisted instrument guidance (CAIG) systems can supplement the existing ultrasound machinery and block needles. CAIG systems allow the operator to navigate the needle in real time while displaying a projected trajectory of its path onto the ultrasound monitor. This study explored how ACBs performed with CAIG compare with conventional ultrasound-only ACBs in terms of block efficiency, success, and potential tissue damage for patients undergoing TKA. Methodology A total of 26 patients undergoing TKA under spinal anesthesia with an ACB were randomized to ACB utilizing conventional real-time ultrasound or to ACB utilizing real-time ultrasound supplemented with CAIG. The primary outcome measure was time to block completion. The secondary outcome measures included number of needle insertions, postoperative pain scores until postoperative day three, postoperative muscle weakness, opioid requirements on postoperative day zero, length of stay, and patient satisfaction with pain management. Results The time required to complete the block as well as the number of needle insertion attempts were similar between the CAIG and conventional ACB groups. Postoperative outcomes such as pain scores up to postoperative day three, postoperative muscle weakness, opioid requirements on postoperative day zero, length of stay, and patient satisfaction with perioperative pain management were comparable between the CAIG and conventional ACB groups. Conclusions CAIG does not reduce ACB performance times or patient outcomes when performed by experienced anesthesiologists.