In the changing healthcare landscape, the integration of 5G-enabled Smart Prosthetics has altered patient care by providing personalized experiences via sensors and real-time data. However, information security remains critical. This research proposes a comprehensive cybersecurity system designed specifically for healthcare informatics. It uses NIST-recommended Lightweight cryptography, such as Ascon, to provide data security in resource-constrained devices. Zero Trust Architecture checks device IDs and gives access according to stringent restrictions. The framework extends from manufacturing to patient engagement, enabling secure local and distant communication with features such as User Credential Updates and key management. Formal and informal security verification show resilience to attacks such as replay, man-in-the-middle, and impersonation. While communication costs are 11% higher, computing expenses are reduced by 12%, increasing energy efficiency. Implementing this framework seeks to provide safe and efficient settings for exploiting 5G-enabled Smart Prosthetics in healthcare informatics.