Changing Stimulation Frequency Improves Implanted Peripheral Nerve Stimulator Effects Following Post-Traumatic Total Hip Arthroplasty: A Case Report.

Total hip arthroplasty (THA) is an effective procedure to improve pain, range of motion, and function for a variety of conditions, including osteoarthritis and post-traumatic arthritis. Up to 28% of patients had persistent pain at the surgical site 12 to 18 months following THA, even in the absence of surgical complications. Currently, there are no widely accepted non-pharmacological treatments for persistent postoperative pain for THA. This case report details the successful management of a 53-year-old man with chronic pain and weakness following post-traumatic THA. He was initially treated with a single-lead percutaneous peripheral nerve stimulator near the right femoral nerve for four weeks with 100 Hz frequency sensory-level parameters. Four weeks after implantation, the frequency was changed to 12 Hz with a goal of motor-level stimulation. During the following three-week time period, his hip flexion strength improved from 10.36 kg to 23.04 kg. His Lower Extremity Functional Scale improved from 35/80 (43.75%) to 54/80 (67.5%) within a five-week time period. This case's success demonstrates how PNS may help improve post-operative persistent pain and weakness in many patients, including those with post-traumatic arthroplasty.