Wilkes v Depuy International Ltd

Under Part 1 of the Consumer Protection Act 1987, a product is defective only if, when supplied, its safety was below the level that persons generally were legally entitled to expect. The assessment is objective and holistic. It must consider all relevant circumstances, including the product’s purposes, warnings, foreseeable use and the time of supply.

For medicinal products, safety is relative. Potential risks must be assessed against potential benefits and utility. Compliance with mandatory standards and regulatory approval is not an automatic defence, but may be powerful evidence of adequate safety. A learned healthcare intermediary and warnings supplied to that intermediary are relevant circumstances. A claimant need not prove why a product failed, but must prove defect and causation.

The claimant’s artificial hip used a metal C-Stem manufactured by the defendant. The stem fractured approximately three years after implantation. The claimant alleged negligence and statutory liability under Part 1 of the Consumer Protection Act 1987, contending that the stem’s design was defective because fatigue failure could have been reduced by alternative design measures.

The trial concerned a preliminary issue limited to liability under section 3 of the Act, having regard to the fracture but excluding metallosis and negligence. The central question was whether the C-Stem’s safety, when supplied, was below the level that persons generally were entitled to expect.

1. Outcome. The preliminary question was answered “No”. The defendant was not liable under the Consumer Protection Act 1987.
2. Applicable statutory test. Section 3 requires an objective assessment of whether the product’s safety was such as persons generally were entitled to expect when it was supplied. “Expectation” means legal entitlement, not what an actual patient or the public in fact expected. The court must consider all relevant circumstances, including the matters expressly identified in section 3(2).
3. Medicinal products. Safety is necessarily relative. The assessment may require balancing risks against potential benefits and utility. The ease or extent to which a risk could be eliminated may be relevant, but avoidability is not a free-standing or determinative issue. The “standard” and “non-standard” classification adopted in A v National Blood Authority was unnecessary and potentially misleading.
4. Standards and regulation. Non-compliance with mandatory standards is evidence of defect. Compliance is evidence that the relevant level of safety has been satisfied, although it is not conclusive. Regulatory approval is neither an automatic nor a prima facie defence, but where the product has undergone detailed expert scrutiny it may be powerful evidence of acceptable safety.
5. Warnings and intermediaries. Warnings qualify the level of safety persons generally are entitled to expect. Where a prosthesis is supplied through a healthcare professional, the professional intermediary, the Instructions for Use and the absence of a statutory obligation to provide information directly to the patient are relevant circumstances. They do not create an automatic defence.
6. Application. The C-Stem complied with the applicable standards and regulatory requirements, had been tested beyond the minimum fatigue criteria, and had a very low reported neck-fracture rate. Its Instructions for Use warned of fatigue failure and identified weight and activity as factors increasing the risk. The fracture resulted from a rare and unpredictable combination of biomechanical variables. The proposed alternative thread designs did not establish that the existing holistic design lacked the required safety.
7. The claimant therefore failed to prove a defect existing when the C-Stem was placed on the market. Causation was not determined because the conclusion on defect was dispositive.

The judgment was a first-instance determination of a preliminary issue ordered by Master Cook. No appellate decision is stated.