Changing Stimulation Frequency Improves Implanted Peripheral Nerve Stimulator Effects After Posttraumatic Total Hip Arthroplasty

Total hip arthroplasty is an effective procedure to improve pain, range of motion, and function for a variety of conditions, including osteoarthritis and posttraumatic arthritis. Up to 28% of patients had persistent pain at the surgical site 12-18 mos after total hip arthroplasty, even in the absence of surgical complications. Currently, there are no widely accepted nonpharmacological treatments for persistent postoperative pain for total hip arthroplasty. This case report details the successful management of a 53-yr-old man with chronic pain and weakness after posttraumatic total hip arthroplasty. He was initially treated with a single-lead percutaneous peripheral nerve stimulator near the right femoral nerve for 4 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 after 3-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 5-wk time period. This case's success demonstrates how peripheral nerve stimulation may help improve postoperative persistent pain and weakness in many patients, including those with posttraumatic arthroplasty.