Sensor technology in healthcare allows for the real-time monitoring of various parameters such as temperature, pressure, and force, which is crucial for diagnosis, chronic care, and the development of advanced medical devices. Orthopaedics would gain significantly from the integration of artificial intelligence, machine learning, and SMART technology for effective data collection and patient tracking. However, traditional orthopaedic implants primarily focus on restoring function without the ability to monitor conditions, which can lead to delayed detection of complications that typically rely on imaging and lab tests. Implantable sensors, which have been around since the 1960s, offer a promising solution by providing real-time insights into the performance of these implants. Modern SMART orthopaedic implants are equipped with wireless sensors that monitor strain, temperature, and pH levels, allowing for the early detection of infection risks and implant loosening. Advances in MEMS and NEMS technologies have led to the miniaturization of sensors suitable for knee and hip replacements. These sensors can be categorized into electric, piezoelectric, optical, thermal, and electrochemical types, all of which are vital for monitoring parameters that contribute to healing and the longevity of the devices. Key challenges such as miniaturization, power supply, and data accuracy are being addressed through innovations in materials and energy-harvesting techniques, while regulatory frameworks ensure their safety and effectiveness. Recent clinical trials have shown promising results, indicating that sensor-enabled implants are likely to become a fundamental aspect of orthopaedic care, improving personalized rehabilitation, patient outcomes, and cost-effectiveness. This review delves into the various types of sensors, the materials used, and the technological integration involved, with an emphasis on enhancing post-operative care in orthopaedics through real-time monitoring of implants.