Brief Summary:Chronic pain affects 1 in 4 US adults, and many cases are resistant to almost any treatment. Deep brain stimulation (DBS) holds promise as a new option for patients suffering from treatment-resistant chronic pain, but traditional approaches target only brain regions involved in one aspect of the pain experience and provide continuous 24/7 brain stimulation which may lose effect over time. By developing new technology that targets multiple, complimentary brain regions in an adaptive fashion, the investigators will test a new therapy for chronic pain that has potential for better, more enduring analgesia.
The investigators have previously found moderately painful massage produces comparable changes in pain sensitivity as a conditioned pain modulation paradigm in healthy participants suggesting shared underlying mechanisms. The researchers aim to extend these findings by understanding the influence of expectation on these findings.
The primary objective of this study is to prospectively determine, at 10 days after orthopedic shoulder or knee surgery, if pulsed electromagnetic field (PEMF) therapy is beneficial in reducing patient-reported post-operative pain, as measured by visual analog scale (VAS). The amount of pain medication taken daily and the physical function outcome scores after surgery and PEMF treatment will also be measured. e