What are FMEA and FTA, and how are they used in rehab engineering?

• A. They are marketing risk assessment tools used for signage.
• B. They are clinical trial statistical methods.
• C. They are risk analysis methods; FMEA identifies failure modes and effects at component/process levels, while FTA analyzes root causes of undesirable top-level events; both guide risk controls and verification.
• D. They are software version control techniques.

Answer: (C)

FMEA and FTA are structured risk-analysis techniques used in rehab engineering to proactively identify and mitigate potential failures in devices and processes.

FMEA examines each component or process step to identify possible failure modes, describe their effects on the system, and assess how severe the consequence might be, how likely the failure is, and how detectable it would be before harm occurs. This helps prioritize which risks to address first and guides where design changes, process controls, or verification activities are most needed, often leading to specific action items and risk-reduction recommendations.

FTA takes a different approach: it starts with an undesirable top-level event, such as a device failure or patient injury, and uses a fault-tree diagram to trace back through logical relationships (AND/OR gates) to uncover combinations of root causes that could lead to that event. It highlights the most influential contributors and common root causes that should be mitigated to prevent the top event.

Used together, these methods drive risk controls and verification strategies in rehab devices—FMEA focusing on component- or process-level failures and their mitigations, FTA clarifying system-level root causes and necessary safeguards. They support safety-focused design, testing, and regulatory risk management for prosthetics, orthotics, assistive devices, and other rehabilitation technologies.