Medical Device Failures Expert Article

In this article, biomedical engineering expert Dr. Farah Hamandi introduces the key concepts related to the failure of medical devices, including internal implants, surgical hardware, external devices, clinical equipment and other biomedical systems. 

Medical Device Failure Investigations

Medical device failures may involve:

• Surgically implanted devices: e.g. joint replacements, stents, meshes
• Surgical hardware: e.g. plate, screw, rod, wires
• External prostheses: e.g. orthotics, prosthetics, ambulation aids
• Medical procedure equipment: e.g. lasers, monitoring systems, drug delivery systems
• Or other biomedical systems e.g. wearable technology

When a device fails or malfunctions, determining the root cause is essential in understanding the mechanism of injury, identifying liability, and evaluating whether the failure/malfunction was preventable. 

Common Modes of Medical Device Failure

Medical devices are often exposed to complex biomechanical loads, chemical environments, patient-specific variables, surgical and device related factors that can lead to failure.

Commonly observed failure mechanisms include:

• Fatigue Failure: Progressive cracking due to repetitive loading, often found in femoral nails, plates, and screws.
• Wear and Surface Degradation: Particularly prevalent in joint replacements, where material loss can lead to osteolysis (bone destruction) and loosening.
• Corrosion: Often observed in modular systems (where components mate), including both dissimilar and similar metals. This may lead to localized pitting, fretting damage, or systemic metal ion release.
• Design-Related Stress Concentrations: Features such as notches, threads, or abrupt transitions that concentrate stress and promote fracture initiation.
• Material Degradation: Polymers such as hydrogels and plastics, oxidative aging can reduce toughness, alter surface morphology, increase particle release, and increase brittleness over time.
• Electronic failure: Sensor/monitor malfunction, delivery system failure, power interruptions.
• User error

A Multidisciplinary Approach to Failure Analysis

Failure analysis in biomedical engineering often involves the integration of mechanical engineering, electrical engineering, materials science, anatomy, and clinical context.

Visual Examination

Initial inspection of failed hardware provides valuable clues. Photographs, optical microscopy and scanning electron microscopy (SEM) are used when necessary to examine fracture surfaces, damage/wear patterns, and microstructural features.

Materials and Metallurgical Testing

For metallic, polymer, and ceramic components, assessing factors such as material composition, hardness, surface treatment, and signs of degradation can be useful to understand device failure.

When appropriate, specialized techniques, such as Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), or X-ray Diffraction (XRD), may be used to characterize corrosion products, contaminants, signs of oxidation, or material changes.

These tools are employed selectively based on the nature of the failure and the questions under investigation.

Clinical and Surgical Correlation

Pre- and post-operative medical records including consultations, operative reports, and radiology images and reports include information about how the device was implanted, the patient’s recovery process, and any deviations from intended use. Factors like bone quality, loading conditions, or surgical misalignment/mismatching may contribute to failure.

Injury Mechanism Reconstruction

Experts analyze the relationship between the failed device and the patient’s diagnosed injury.

Did the device failure result in additional treatment, produce injury, or is it a symptom/manifestation of an underlying problem?

Biomedical expertise is applied to determine how and why a device failed. If a specific traumatic incident is in question, a biomechanical investigation applies fundamental principles of physics and engineering to analyze whether the loading experienced during the incident generated the necessary forces to cause the failure and/or injury described.

Medical Device Failure Analysis Expertise

Medical device failures are rarely the result of a single issue. Instead, they emerge from a combination of mechanical stress, material performance, clinical decisions, patient parameters and other factors. The performance of a device may be related to the design or manufacturing. 

The biomedical experts at Robson Forensic are engaged when the cause of a device failure is not known, not understood, or is in dispute, particularly when such failures result in serious injury or raise questions of product defect, surgical technique, or preventability.

For more information, visit our Medical Device & Research Laboratory page or submit an inquiry.

Featured Expert

Farah Hamandi, Ph.D.

Biomedical Engineer & Biomechanics Expert

Dr. Farah Hamandi is a biomedical engineer with specific expertise in biomechanics and biomaterials. She applies her expertise to forensic casework involving traumatic injuries including motor… read more.