When medical devices fail, a key question is “why?” Was it a device defect, misuse by the user, or something in between? Recent analyses of FDA data, including recall studies and MAUDE reports, shed light on how often user error or device defect is listed as the primary cause. Understanding this split helps teams reduce risks and improve design.
1. Recall Data: Why Devices Get Pulled From Market
A review of FDA recall records from 2014–2023 shows that recalls attributed solely to user error made up only about 0.93% of total cases. In contrast, software-related issues, especially UI design flaws, accounted for 5.44% of recalls overall and nearly 46% of recalls tied to software errors. Many of these “user errors” actually stem from poorly designed interfaces that confuse operators.
Another study of Class I recalls between 2014 and 2018 found that almost 40% of cases might have been misclassified, often merging device design defects with component or quality issues.
2. MAUDE Data: Event Types and Causes
Rhinolaryngoscopes Case Study
From 2016 to 2023, the MAUDE database recorded 2,591 reports of rhinolaryngoscope device issues. Of these:
- 40.8% involved breakage
- 24.4% were fluid leaks
- 18% stemmed from poor image quality
Many of these device malfunctions led to injuries, with investigation pointing to improper handling, excessive force, or missing maintenance, cases that combine device wear with user contribution. Equipment misuse and inadequate ergonomics contributed substantially to adverse event.
Robotic Surgery Reports
An analysis of surgical robots (e.g., da Vinci systems) showed 84.5% of malfunctions linked to instruments, 81.7% occurring during surgery. Patient injuries occurred in 15.6% of malfunction events, including injuries from device malfunction (6.6%), operator misuse (18%), and procedure-related complications (15.6%).
3. Device Failure vs. User Error: Which Is More Common?
Behavioral repair logs from medical facilities indicate that user error or physical damage often accounts for 10–50% of maintenance cases. Some professionals report as high as 80–90% of device issues trace back to misuse or user-related damage, rather than inherent defects.
In diabetes devices (blood glucose meters, insulin pumps, CGMs), MAUDE data from 2018–2019 reveals hundreds of thousands of malfunctions with fewer injuries and deaths, suggesting that many events relate to user misuse or setup errors rather than lethal device failure.
4. Why Classification Matters
FDA defines device-related events broadly: covering failure, malfunction, design issues, labeling defects, manufacturing issues, and user error. Any event that contributed, even indirectly, could trigger a mandatory report.
However, ADA’s root cause categories are inconsistently applied. “User error” is often coded when real underlying issues are flawed design, unclear labeling, or poor ergonomics. This tends to undercount design risks and over-attribute blame to users.
5. Human Factors in Design Errors
User error often reflects poor human factors design, like confusing button layouts, ambiguous prompts, or software flows that lead to misuse. A study found that less than 20% of physicians followed recommended reprocessing steps for high-level disinfection, leading to device contamination and harm.
Case reports show contamination-related outcomes, even severe ones, are linked more to process and usability than device component breakdown.
6. Comparing Risk Profiles
- Device defects, like mechanical failures, broken materials, or miscalibration, are often easier to trace and quantify. In rhinolaryngoscopes, design-related malfunctions accounted for nearly 65% of total issues (breakage, leakage, poor image quality).
- User-related issues, such as misuse or misinterpretation, account for a smaller share of recall-labeled events. Yet in real-world usage, these errors appear in many injury outcomes, especially with complex or poorly designed medical devices.
7. Implications for Medical Device Teams
Focus on Human-Centered Design
Many user errors are predictable if the device and user interface aren’t intuitive. Design improvements, clear labels, training, and ergonomic controls, reduce misuse.
Better Root Cause Classification
Firms and regulators should refine event categories and separate design flaws from user mistakes. This improves prevention strategies and device improvements.
Training and Documentation
When user error occurs, retraining should include design feedback. Training alone won’t solve misuse if the UI or workflow remains faulty.
Improved Vigilance and Feedback Loops
Collect detailed event data, review usage errors, and track trends. Continuous vigilance helps teams identify whether recurring injuries stem from misuse or inherent device weakness.
8. Summary Table
| Cause Type | Estimated Share | Examples |
| Device defect | ~40–60% of malfunctions | Breakage, leakage, poor image |
| Design-related misuse | ~5–15% of recalls | UI flaws leading to user errors |
| Operator error/use mistakes | Up to 50% in facility repair logs | Misassembly, improper cleaning, misuse |
Conclusion
FDA data and case studies show that both device defects and user interaction issues contribute to adverse events. True user error is relatively rare in recalls, often under 1%, but misuse due to flawed design or unclear instructions is much more common.
Medical device teams must balance two goals: build safe, robust products and design for real users in real environments. When product design guides the user toward safe behavior, both device errors and misuse-related injuries fall.
By digging deeper into cause attribution and improving human factors design, teams can reduce risk and build safer products for patients, providers, and regulators alike.
