In pharmaceutical or medical device litigation, lawsuits generally arise from design or manufacturing defects, plus failures to warn. These forms of product liability are distinct legal principles that can determine how a lawsuit is investigated and what evidence may be needed to support a plaintiff’s claims.
Design defects occur when there is an inherent flaw in a product’s blueprint or plan. The design itself presents an unreasonable risk of harm to consumers, which means every unit produced is affected, including those manufactured exactly as intended.
Courts, depending on jurisdiction, generally use one of two tests, or a combination of both, to evaluate a design defect claim.
Consumer Expectations Test: Applied when the product failed to perform as safely as an ordinary consumer would expect when used as intended.
Risk Utility Test: Applied when the risks of the product’s design outweigh its benefits, and a safer, feasible alternative design exists.
Design defect example: Litigation against C.R. Bard (now a subsidiary of Becton, Dickinson and Company), alleges that Bard’s Powerport contains a dangerous design defect that makes it unsafe for patients. These lawsuits allege a flaw in the design of the port catheter makes it prone to device fractures and migration, resulting in serious harm to users, including blood clots, infection, and other severe injuries after implantation.
Unlike design defects, manufacturing defects occur during the production, assembly, or distribution process. The product's design may be sound, but something went wrong during manufacturing that caused a specific unit or batch to deviate from the intended design.
Manufacturing defects can occur due to multiple factors, including the use of substandard materials, contamination during manufacturing, or human error. Manufacturing defect claims generally fall under the principle of strict liability, meaning that the plaintiff must only show that the product deviated from its intended design or contained a defect and that the defect or deviation caused the harm. A plaintiff need not prove the manufacturer was negligent under strict liability.
Manufacturing defect example:
Ongoing litigation filed against Dexcom, the manufacturer of the Dexcom G6 and G7 continuous glucose monitoring systems, alleges that the devices contain dangerous design and manufacturing defects. Manufacturing defects include modifications made during the production process that substituted substandard materials, which made the devices less effective.
The simplest way to understand the difference between a design and a manufacturing defect: a design defect means the blueprint itself is flawed, so every unit is affected. A manufacturing defect means the blueprint is fine, but something went wrong during production, so only certain units are affected.
This distinction changes what must be proven and what evidence is needed. In a design defect case, plaintiffs may need engineering analysis or expert testimony showing that a safer alternative design was feasible. In a manufacturing defect case, the key evidence is usually quality control records, inspection reports, and internal production documents that reveal where the process deviated from the design.
In practice, the line between the two is not always clear. A defect that appears in every unit might still be argued as a manufacturing issue, and some cases involve both claims of design and manufacturing defects involving the same product.
Manufacturers may also face liability under a third theory: failure to warn. This applies when a manufacturer knew or should have known about a risk associated with the product but failed to provide adequate warnings or labeling to consumers.
For medical devices, failure to warn claims often involve insufficient labeling about known side effects or complications. These claims are frequently brought alongside design or manufacturing defect claims, particularly when a company allegedly continued to market a device as safe despite evidence of risk.
The causes of action in a legal case involving a medical device shape the legal strategy your attorneys use. A design defect case requires different experts, different evidence, and a different theory of liability than a manufacturing defect case. Getting this classification right early in the process is critical.
Medical devices also face a unique legal landscape because of the FDA. Devices go through different approval pathways depending on their risk classification. Many devices reach the market through the 510(k) pathway, which requires the manufacturer to show only that the device is “substantially equivalent” to an existing product already on the market — not that it has been independently proven safe through clinical trials. Higher-risk Class III devices must go through the more rigorous Premarket Approval (PMA) process.
This distinction matters in court because manufacturers of PMA-approved devices may argue that FDA approval of the device’s design shields them from state-law design defect claims — a legal defense known as federal preemption. The U.S. Supreme Court recognized this defense in Riegel v. Medtronic, Inc. (2008).
But manufacturing defect claims may still proceed, because FDA approval covers the design, not whether the manufacturer actually followed that design during production. It is also important to remember that medical devices cleared through the 510(k) pathway do not receive the same preemption protection.
Spinal cord stimulator litigation illustrates how all three theories of liability can apply to a single type of device. Lawsuits allege that certain spinal cord stimulators are inherently prone to lead migration and electrical malfunction due to flaws in their design (design defect), that specific units were produced with structural weaknesses in the lead wires and insulation failures that deviated from approved specifications (manufacturing defect), and that manufacturers withheld critical information from patients and doctors about known failure rates and complications (failure to warn).
Patients who believe that they have suffered harm from a medical device are encouraged to seek medical attention immediately. Keep a detailed record of any injuries or illnesses potentially linked to the device, and preserve device packaging, labeling, or safety communications. Document any symptoms that may be attributed to the allegedly defective device and check the FDA’s recall database to see if the product has been subject to a recall or urgent safety communication.
Once you are able, contact an attorney experienced in medical device litigation. The legal team at Wisner Baum has represented thousands of clients nationwide in product liability claims, including those involving medical devices. Contact us at (310) 207-3233 to discuss your legal claim.
Yes. The Dexcom CGM litigation is one example where plaintiffs allege both types of defects in the same product — flaws in the device’s design as well as production changes that introduced substandard materials.
Strict liability means a plaintiff does not have to prove the manufacturer was careless or negligent — only that the device was defective and the defect caused harm. This standard applies in many jurisdictions, particularly for manufacturing defect claims, because the defect can be measured against the manufacturer’s own design specifications.
Not necessarily. Many devices reach the market through the 510(k) pathway, which requires only that the device is “substantially equivalent” to a product already on the market. A device can have FDA clearance and still contain a defect.
Yes. A recall is a regulatory action. Some medical devices that plaintiffs allege are defective in lawsuits are never recalled by the FDA. The absence of a recall does not necessarily mean a device is safe, nor does it prevent an individual from filing a product liability claim.
Individuals who file a successful defective medical device lawsuit may recover compensation related to medical bills, lost wages, pain and suffering, and loss of future earning capacity.
