CASE: A male patient in his late 50s had attempted removal of an interscalene block catheter after reverse total shoulder arthroplasty. Atypical pain and resistance raised concern for entrapment in the brachial plexus, requiring surgical exploration. It was found to have knotted in the anterior and posterior divisions of the upper trunk of the brachial plexus. Under direct visualization, the catheter was removed and the brachial plexus was unharmed. CONCLUSION: This case raises awareness that if unexpected pain or resistance is encountered during nerve block catheter removal, it is vital to pause and evaluate the possibility of entrapment in neural structures.