Current Status and Future Perspectives of the Active Knee Joint Rehabilitation Device

Background: Today, living standards and medical technology are improving, and the aging global population is increasing. However, more and more older adults are suffering from knee diseases. This will seriously affect patients’ daily life and their mental state. In many studies, repetitive physical exercises and motor activities in real-world environments have been shown to help improve knee muscle strength and restore damaged nerves. Therefore, physical knee therapy is very necessary. The use of rehabilitation training devices for movement therapy has shown great potential. Objective: This study aimed at exploring the structural features, functions, and development status of the knee rehabilitation training device. Methods: This review explores the structure and function of various current knee rehabilitation devices based on structural and kinematic properties of the knee joint in relation to requirements of physical knee rehabilitation. This paper aims to present a systematic guideline and outline a reference for future designers of rehabilitation devices. Results: By analyzing the structure and movement of the knee joint and combining the strategies of physical knee rehabilitation, movement requirements during knee rehabilitation training are concluded. According to the structure, drive form, transmission mode, and rehabilitation environment of knee rehabilitation devices, the devices are classified and compared; some typical features are summarized; some current problems are analyzed, and the future trends and development directions of rehabilitation devices are discussed. Conclusion: Current rehabilitation equipment has a variety of structures and functions, but a good balance between weight and volume is hardly maintained. The protection of the body needs to be further improved. Many knee rehabilitation devices are only concepts, not physical objects, and lack clinical trial data. Power sources and drives are large and heavy, which can compress the knee joint and burden the patient. Strong and lightweight materials should be chosen to assist knee rehabilitation. It will be a good development in the future.