Sensor-based technology uses either embedded or surface-wearable devices to detect physical (such as pressure, speed, acceleration, and force), chemical (such as ions), and biological signals, which, integrated with information and communications technology (ICT), provide a way of analyzing these signals. The Industry 4.0 revolution, the development of Industry 5.0, and innovations in computer and design technology have allowed the development of SMART (self-monitoring analysis and reporting technology) implants. Sensor-based technology has various medical applications and has been utilized in diagnosing, treating, and monitoring diseases. The combination of sensor-based technology and SMART implants has been increasingly applied in managing a spectrum of musculoskeletal conditions to provide improved diagnostic, monitoring, and therapeutic roles. Joint replacement arthroplasty in end-stage arthritis due to a spectrum of etiologies such as degeneration, trauma, or inflammation of a joint has shown many benefits, including pain relief, improved mobility, and a better quality of life (QoL). However, successful outcomes following joint replacement arthroplasty, such as total knee arthroplasty or total hip arthroplasty, depend on pre-operative planning, meticulous surgery, and effective rehabilitation. Sensor-based technology with embedded SMART implants allows real-time intraoperative positioning of arthroplasty implants. It improves kinematics, postoperative monitoring of patients’ rehabilitation and long-term surveillance of joint replacements. In this chapter, we provide an overview of the principles of sensor technology, the evolution of SMART implants, and their current roles and future applications in joint replacement arthroplasty in improving patient outcomes.