Resolving the Conflict Between Regional Analgesia and Developing Compartment Syndrome in Below-Knee Surgeries With the High-Volume Proximal Adductor Canal (Hi-PAC) Block: A Prospective Feasibility Study

The consideration of regional analgesia (RA) in below-knee surgeries is always a controversial topic due to the fear of masking symptoms of developing compartment syndrome (CS) in the postoperative period. Compartment syndrome (CS) has been found frequently in below-knee surgeries, particularly among tibial diaphyseal fractures. Like any other surgery, below-knee surgeries have significant postoperative pain that requires effective postoperative analgesia protocol. The analgesia quality makes a big difference when compared with or without RA. Also, the presence or absence of RA cannot prevent or promote the development of CS. Therefore, patients should not be deprived of their right to remain pain-free in the postoperative period by compromising the analgesia protocol. The pain out of proportion to the surgery or injury is a typical symptom of developing CS, which can cause increased analgesic demands postoperatively. Timely diagnosis and treatment of CS require vigilant postoperative monitoring of the warning signs by trained staff. Avoiding RA for fear of presumed masking of symptoms and delaying CS diagnosis may not be a solution instead of choosing an appropriate RA with regular postoperative monitoring for such warning symptoms. The high-volume proximal adductor canal (Hi-PAC) block has been described as a procedure-specific and motor-sparing RA technique appropriate for below-knee surgeries. In this prospective study, we evaluated the analgesic efficacy of the Hi-PAC block in below-knee surgeries. We also observed the effect of the Hi-PAC block, due to proximal and distal drug distribution, on masking the symptoms of the developing CS during postoperative monitoring. We found the Hi-PAC block to be a safer and more effective RA alternative for below-knee surgeries with an added motor-sparing benefit that facilitated early mobility and discharge. Its property of not interfering with postoperative surveillance to detect the symptoms of CS and intervene in time helps deal with the anxiety of CS in below-knee surgeries.