Federal Court of Justice Ruling Brings Clarity on Design Defects and Safety Expectations

No Product Liability for the Fracture of a Ceramic Inlay in a Hip Prosthesis – BGH Strengthens Manufacturers

Background of the Case

A patient suffered a fracture of the ceramic insert (“inlay”) of her total hip replacement after implantation. She sued the manufacturer for damages and compensation for pain and suffering. Both the Regional Court and the Higher Regional Court dismissed the claim. The Federal Court of Justice (BGH) has now confirmed these decisions (Judgment of 1 August 2023 – VI ZR 82/22).

The central question: When does a product defect exist within the meaning of the German Product Liability Act (Produkthaftungsgesetz – ProdHaftG)?

Decision of the Federal Court of Justice

The BGH clarified:

• No manufacturing defect: It could not be proven that the specific fracture resulted from a manufacturing error. Circumstantial evidence (“prima facie proof”) did not apply, as there was no typical sequence of events pointing directly to a production defect.
• No design defect: While 36 mm inlays had a higher risk of fracture than smaller models, this reflected the state of the art and was linked to advantages – such as greater mobility and a reduced risk of dislocation. According to the BGH, risks may be accepted if they are technically unavoidable and outweighed by substantial benefits.
• No failure to warn: In 2007, the manufacturer was not required to warn about an increased fracture risk, since such cases only became known from 2009 onwards.
• No application of CJEU case law on pacemakers: Unlike highly sensitive, life-sustaining devices, the situation here did not involve a comparable risk scenario.

Key Legal Principles

• Objective safety expectations are decisive – The relevant benchmark is not the patient’s subjective expectation but the objective perspective of the public and the state of science and technology at the time of market release.
• Risk assessment instead of “zero risk” – Absolute product safety is not required. Risks can be tolerated if they are unavoidable and outweighed by benefits.
• Burden of proof lies with the claimant – Under § 1(4) ProdHaftG, the injured party must prove both the defect and causation.

Two Highlights from the Judgment

1. On the manufacturer’s duty to warn:

“If dangers inherent in the use of a product cannot be avoided by constructive measures according to the state of science and technology, or if such measures are unreasonable for the manufacturer, and if the product may nevertheless be placed on the market despite its dangers, the manufacturer is generally obliged to warn users of those dangers which may arise from intended use or foreseeable misuse and which are not part of the general knowledge of the user group. Users must be enabled to make an informed decision on whether, in light of the product’s benefits, they are willing to accept the associated risks. They must also be put in a position to counteract the risks as far as possible.”

1. On the definition of a design defect:

“A design defect exists if the product, by its very conception, falls below the required safety standard. To ensure product safety, the manufacturer must, already at the design and planning stage, take those measures that are objectively necessary and objectively reasonable to avoid danger (…). The required safeguards are those which, at the time the product is placed on the market, are constructively feasible according to the latest scientific and technical knowledge and appear suitable and sufficient to prevent damage. The possibility of avoiding the danger exists if practically applicable solutions are available according to established expertise in the relevant field. Such a superior alternative design must be sufficiently mature for serial use.”

Background on Product Liability in Medical Device Law

Natural or legal persons may claim compensation for damage caused by a defective product under applicable Union law and national law. This follows from Article 10(16) of Regulation (EU) 2017/745 (MDR). In German law, liability is based in particular on § 823 of the German Civil Code (BGB) and the Product Liability Act (ProdHaftG).

The general safety and performance requirements of the MDR are decisive. If they are not met, the medical device is deemed defective. Manufacturers are therefore obliged under Article 10(16) MDR to maintain sufficient financial coverage for potential liability cases.

Potential liability is defined in Directive 85/374/EEC and identically in § 3 ProdHaftG (Defect):

• § 3(1): A product is defective if it does not provide the safety which one is entitled to expect, taking all circumstances into account, in particular
  a) its presentation,
  b) the use to which it can reasonably be expected to be put,
  c) the time it was put into circulation.
• § 3(2): A product is not defective solely because a better product is subsequently put on the market.

Significance for Patients and Manufacturers

For patients, the ruling means: Not every adverse event automatically creates a claim against the manufacturer. Proof of a specific product defect is required.

For manufacturers, the decision is significant because it confirms the principle that product liability does not guarantee absolute error-free performance. Risks that are unavoidable do not have to be excluded entirely, provided they are manageable under scientific standards and transparently balanced against the benefits.

Practical Implications

• For patients: Those seeking damages must provide medical expert opinions establishing a specific product defect.
• For doctors and hospitals: The selection of prosthetic components requires careful assessment of the patient’s individual circumstances.
• For manufacturers: Comprehensive documentation of development, testing, and risk assessment remains essential to minimize liability risks.

Conclusion

The Federal Court of Justice has made it clear: A fracture alone does not establish product liability. Manufacturers are only liable for products that are objectively defective – not for all unavoidable risks. The ruling strengthens legal certainty while also clarifying the limits of product liability.