A ‘prosthesis life-cycle ontology’-based service system framework to cater for amputees’ evolving needs

Abstract

Lower-limb prostheses remain essential to restoring mobility and independence for amputees, yet their design and aftercare continue to be fragmented, reactive, and inefficient. Current practices are characterised by siloed stakeholder input, tacit rather than structured knowledge, and limited methods for adapting to the evolving needs of both amputees and prosthesis sub-systems. This thesis addresses these systemic inefficiencies by developing the Adaptive Prosthesis Life-Cycle Service System Framework (adProLiSS), an ontology-based, consequence-aware framework that reconceptualises prosthesis management as an integrated product–service system (PSS). The research aim was to improve amputees’ overall prosthesis experience, measured in terms of time efficiency, cost efficiency, functionality, user comfort, emotional well-being, and aftercare quality, through the design, implementation, and evaluation of a prosthesis life-cycle framework that supports adaptive, knowledge-based decision-making. To test this aim, seven research questions (RQ1–RQ7) were formulated, spanning the identification of life-cycle activities, stakeholder roles, tools and methods, critical constraints, specifications of a prosthesis PSS, and its applicability and evaluability across prosthesis types. Conceptually, the thesis advances the state of the art by introducing the Prosthesis Life-Cycle Consequence Knowledge Modelling Frame (PLCCKMF), a domain-specific ontology that formalises heterogeneous consequence knowledge, including intended and unintended, interacting and non-interacting outcomes, across physical, functional, emotional, systemic, and semantic domains. Methodologically, the work contributes a closed-loop life-cycle methodology, digital tool support through the Patient–Prosthesis Management System (PPMS) and the Consequence-Driven Co-Design Support Tool (CD-CST), and a scenario-based evaluation strategy combining physical demonstrators, digital platforms, and stakeholder engagement. Practically, these contributions were validated through prototype demonstrations addressing ulcer detection, weight distribution monitoring, fall risk, maintenance alerts, and daily logging. Evaluation findings indicate that adProLiSS delivers measurable improvements across the six evaluation criteria, enhances stakeholder collaboration, and enables decision traceability in ways not achieved by conventional approaches. The framework was shown to reframe amputees from passive recipients to active contributors of consequence knowledge, support clinicians in preventive and evidence-based aftercare, and allow engineers to anticipate design consequences before physical prototyping. The findings carry implications for service providers and policymakers, particularly in highlighting how consequence awareness and interoperability standards such as HL7/FHIR could guide future procurement practices and rehabilitation service models. The research is not without limitations. The scope was bounded to lower-limb prostheses, early-stage digital and physical prototypes, and a geographically localised but scientifically justified stakeholder sample. Nonetheless, the framework establishes a demonstrable foundation that can be extended to upper-limb prostheses, scaled through multi-centre evaluations, and advanced via ontology governance methods and higher-TRL digital systems. Future work also envisions adProLiSS as an educational simulator and as a bi-directional communication platform for real-time patient–clinician interaction. In conclusion, this thesis contributes to engineering design knowledge by embedding consequence awareness and ontology-driven reasoning into the prosthesis life-cycle, demonstrating how structured knowledge representation and adaptive service-system integration can improve both design and aftercare. The adProLiSS framework thus stands as a novel paradigm for prosthesis life-cycle management, bridging conceptual, methodological, and practical advances, and as a commitment to enhancing the lived experiences of amputees through more collaborative, knowledge-based, and adaptive healthcare systems.