A research team from the Massachusetts Institute of Technology in the United States has developed a new type of "bionic knee" joint prosthesis, which can help amputees walk faster and more easily complete complex movements such as climbing stairs and crossing obstacles compared to traditional prostheses. This achievement was published in the latest academic journal, marking a significant leap in prosthetic technology from passive assistance to active perception and intelligent control. The traditional prosthetic system places the residual limb in the receiving cavity, while this new device is directly integrated with the user's muscles and skeletal tissue, thereby improving stability and allowing the user to control the prosthetic more naturally, as if it were a part of their body. The team pointed out that this "integrated prosthetic" is not only an external tool, but also an intelligent device highly integrated with the human physiological system, allowing users to gain a stronger sense of "limb belonging". The innovation of this system lies in the combination of a new surgical method called agonist antagonist muscle neuron interface (AMI). This method involves surgically reconnecting muscle pairs to maintain dynamic interaction within the residual limb, providing sensory feedback, and generating electrical signals that can be used to control the prosthetic. On this basis, the team developed an integrated system that not only reads signals from AMI muscles, but also implants prosthetics into bone structures, achieving higher stability and more precise motion control. The team designed a titanium rod implantation technique to insert it into the residual femur at the site of amputation. This implant not only enhances mechanical control and load-bearing capacity, but also has 16 built-in wires that can obtain information from AMI muscle electrodes located inside the body, thereby more accurately capturing muscle signals and converting them into prosthetic movements. This integrated system is called e-OPRA (electronic bone integration prosthetic system). In the experiment, two subjects received AMI combined with e-OPRA implantation. The team compared its performance with 8 other users who only accepted AMI but did not implant e-OPRA, as well as 7 users who had neither AMI nor e-OPRA. All participants were tested using laboratory developed powered knee prostheses. The test includes tasks such as bending the knee to a specified angle, climbing stairs, and crossing obstacles. The results showed that in most tasks, subjects using the integrated system performed better than the other two groups, especially in tasks that required fine control and dynamic balance, where the advantage was more pronounced. (New Society)