Safety Challenges and Gaps for Bionic Knee Prostheses: An Introductory Survey

Bionic knee prostheses enable assistance and adaptive locomotion, but their increasing autonomy raises unresolved safety and regulatory challenges. Control complexity, limited disturbance recovery, and insufficient fault tolerance can compromise user stability and increase fall risk. At the same time, safety across technical frameworks, evaluation protocols, and regulatory guidance for these systems remains fragmented and poorly aligned with real-world use. This introductory survey structures the main safety-related challenges of bionic knee prostheses, reviews representative technical approaches, and highlights related gaps and future directions. By organizing these issues, the paper aims to support the development of future safety frameworks, testing protocols, and regulatory pathways for powered knee prostheses.