Court rules in favour of manufacturers in first metal on metal hip replacement case in Scotland

Facts

In the case of Hastings v Finsbury Orthopaedics Ltd and Stryker UK Ltd [2019] CSOH 96, Mr Hastings brought a claim under Section 2 of the Consumer Protection Act 1987 (“the CPA”) against the manufacturers of the two component parts of his MoM THR prosthesis (“the Product”). The CPA imposes no-fault liability on producers and importers if personal injury is caused by a defective product. In particular, Mr Hastings contended that the Product, which he had had implanted in 2009 and revised in 2012, was defective in that its safety was not as persons generally are entitled to expect (Section 3).

The issues

The question for determination was whether certain risks and propensities inherent in the Product rendered it less safe than persons generally were entitled to expect, and therefore “defective” within the meaning of the CPA. To answer this, parties agreed that a 2-stage approach was required, the key questions being:

• What was the “entitled expectation” of persons generally in respect of the Product; and
• Did the Product fail to meet this entitled expectation?

Entitled expectation

Lord Tyre considered the lead authorities on the issue of “defect”, namely the English decisions of Wilkes v. DePuy International Limited [2017] All ER 589, and Gee and others v. DePuy International Limited [2018] EWHC 1208 (QB). He found them to be relatively uncontroversial and helpful. He specifically agreed with Hickinbottom J’s decision in Wilkes that the test for safety requires an objective approach to what persons generally are entitled to expect; and with Andrews J’s statement in Gee that a flexible approach should be taken to the circumstances that may be relevant to assessing the safety of a product.

However, in reaching his conclusion on the formulation of “entitled expectation”, Lord Tyre rejected the formulation set out in Gee: Mr Hastings had argued that the entitled expectation of the Product was that it would be at least as good as alternatives, whereas the manufacturers claimed – in line with Gee - that the Product should not be materially worse than those it was intended to replace. Lord Tyre rejected the Gee formulation preferred by the manufacturer, stating that it imposed an unnecessary burden on the claimant. Instead he set a lower bar for the entitled expectation test, namely that “subject to de minimis considerations, its level of safety would not be worse, when measured by appropriate criteria, than existing non-MoM products that would otherwise have been used.”

There were two other distinctions in the way the Scottish court approached “entitled expectation” compared to the approaches taken in Wilkes and Gee. Firstly, the Scottish decision was at odds with the prior decisions in relation to when defectiveness fell to be assessed: Section 3(2) of the CPA provides that “the time when the product was supplied by its producer to another” is a circumstance which shall be taken into account in determining what persons generally are entitled to expect as regards the safety of a product. The English cases approached this point by considering defectiveness at the time at which the product in question was put into circulation. However, in Hastings, the parties agreed that the ‘date of supply’ was when the Product was implanted in Mr Hastings. Lord Tyre fully recognised the inherent divergence of approach, stating that he had been assured that in Gee “it was agreed that nothing turned on whether the time of supply was taken to be the date when the product was first put on the market or, alternatively, any of the various dates on which prostheses were supplied to the claimants”.

Whilst in many cases this divergence of approach may have little impact on outcome, in developing areas the question of when defectiveness falls to be assessed may be a material issue, and further clarification on the approach to ‘time of supply’ will be welcomed.

The second point of interest in Lord Tyre’s consideration of entitled expectation, was the weight he attached to the Information for Users (“IFU”) supplied with the Product. According to Section 3 of the CPA, “any instructions for, or warnings with respect to, doing or refraining from doing anything with or in relation to the product” should be taken into account when considering what people are entitled to expect with regard to the safety of a product. In applying this provision, the English cases have confirmed (most notably Hickinbottom J in Wilkes) that IFUs are relevant and form part of the factual matrix a judge will consider when assessing entitled expectation. In the case of prosthetics, where there is always a learned intermediary between the producer and the patient, the IFU was considered relevant to the learned intermediaries in coming to a professional view on intervention choices, and remained a valid consideration when assessing entitled expectation as between manufacturer and consumer.

However, despite having heard evidence that IFUs were intended to be read by surgeons carrying out operations, Lord Tyre was sceptical as to whether the IFUs in this case “had (or were expected to have) any real practical value”. He specifically referred to the fact the instructions were in very small typeface and “were in highly general and heavily qualified terms”. Lord Tyre accordingly concluded that the IFU in this case would have “no significant effect” on the entitled expectation test and added little to a surgeon’s knowledge.

Given the importance manufacturers and producers attach to providing warnings and instructions in their IFUs, the dismissal of an IFU as being of “little weight” to considerations of safety and defectiveness will be of interest to manufacturers. It appears that the instructions in Hastings were particularly general and heavily qualified, perhaps owing to the Product still being relatively new (reference is made to the Product not having 10 years of outcome data at the time of implant).

Did the MoM product meet the entitled expectation?

The key issue for Mr Hastings was, however, whether he could establish a causal link between the creation of metal debris from MoM THR products and damage to the body around the site of the prosthesis.

While Lord Tyre found that Mr Hastings had established that there may be a link, the evidence suggested this was present in only a minority of cases and in limited circumstances. It could not therefore be said that the reason for the damage around the site of the prosthesis was necessarily related only to MoM THRs. As Lord Tyre was not satisfied that the necessary causal link had been established on the balance of probabilities, Mr Hastings’ claim failed.

One of the challenges for Mr Hastings was lack of data regarding MoM products generally, including the one he received. His prosthesis had been implanted in 2009. By around 2012, only three years after his procedure, the consensus among the medical community was that failure rates of MoM THRs were higher than expected and compared unfavourably to other types of total hip replacement. As a result, their usage declined. As the implants were only used for a short period of time, the availability of evidence on their effectiveness was substantially curtailed and was less than the minimum benchmark for the Orthopaedic Data Evaluation Panel (which was ten years of outcome data to enable a view to be reached on the clinical efficacy of a product). In summary, the lack of data available to evidence the safety of MoM products meant the court was unable to reach an objective conclusion that people were entitled to expect the improved outcomes that many of the orthopaedic professionals had hoped, and even believed, MoM products would deliver.

Concluding comments

Although Mr Hastings was ultimately unsuccessful, this decision will have implications for the defence of future product liability cases in Scotland. The decision is not a death knell for the various other claims for potentially defective MoM THR products. Lord Tyre specifically commented:

“In holding that the pursuer in the present action has failed to prove that the product supplied to him was defective, I do not exclude the possibility that another pursuer might be able to present evidence in relation to a different product sufficient to establish, on balance of probabilities, that entitled expectation in relation to that product had not been met.”

With regard to product liability claims more generally, manufacturers and their legal counsel are likely to watch with interest for further decisions clarifying the entitled expectation test – its formulation, timing and the role of IFUs - and how it is to be applied north and south of the border.