The Upper-Limb Residual Limb as a Biological Control Interface: Surgical Preparation, Myoelectric Signal Optimization, Rehabilitation, and Neural Prosthetic Integration—A Narrative Review

Background/Objectives: Upper-limb prosthetic performance depends not only on the mechanical and computational capabilities of the device but also on the quality, selectivity, stability, and accessibility of biological signals available within the residual limb. Methods: A structured narrative search of PubMed/MEDLINE, Scopus, Web of Science Core Collection, IEEE Xplore, targeted Google Scholar searches, and citation chaining was conducted through 11 August 2026. The final synthesis included 111 publications and examined muscle architecture, intervening soft tissues, nerve management, electromyographic control, rehabilitation, surgically created interfaces, implanted sensing, osseointegration, and sensory feedback. Results: Particular attention is given to an earlier developmental research line involving myoelectric acquisition, personalized training, residual-muscle redistribution, fascial signal transmission, nerve mapping, and implantable neural sensing, which is critically contextualized against independent contemporary evidence. Exploratory residual-limb surgical approaches are distinguished from interventions with stronger clinical support. Conclusions: On this basis, we propose the concept of interface-conscious upper-limb amputation: the preservation, organization, accessibility, training, and longitudinal adaptability of the biological structures required for present and future prosthetic control. This framework is not a validated surgical protocol, but a clinically oriented synthesis intended to connect amputation surgery with rehabilitation, neuroprosthetics, and long-term technological evolution.