NEUROCUPLE™ as an Opioid Alternative Following Total Knee Arthroplasty

The goal of this clinical trial is to learn if the NEUROCUPLE device can reduce pain and opioid use after primary unilateral total knee arthroplasty (TKA) in adults. The main questions it aims to answer are: * Does the NEUROCUPLE device reduce postoperative pain at rest during the first 24 hours after TKA? * Does the NEUROCUPLE device reduce opioid consumption during the first 24 hours after TKA? Researchers will compare the NEUROCUPLE device to a placebo device (identical in appearance but inactive) to see if the device reduces pain and opioid use after surgery. Participants will: * Apply the NEUROCUPLE device or placebo device for 7 days following surgery * Have their pain and opioid use monitored through clinical records and patient reporting * Report pain at rest and during movement on postoperative Days 2 and 7 * Be assessed for nausea, vomiting, device-related side effects, length of hospital stay, and overall satisfaction