Damages action over ‘defective’ metal-on-metal hip replacement product dismissed

John Hastings, 64, claimed that the metal on metal (MoM) total hip replacements (THR) used in his operations were “defective” because their safety was not such as people generally were entitled to expect, but a judge in the Court of Session ruled that the pursuer failed to prove that there was a defect in the product.

‘Metal on metal total hip replacement’

Lord Tyre heard that the pursuer, who has a history of arthritis, underwent metal on metal (MoM) total hip replacements (THR) on both sides of his body in 2009 at the Golden Jubilee National Hospital.

The metal parts that made up the artificial hips were manufactured by the defenders Finsbury Orthopaedics Limited and Stryker UK Limited, who entered into an agreement in 2005 to develop the Mitch/Accolade product, which was designed to replicate successful MoM hip resurfacing devices on the market at that time.

The court was told that MoM THRs were developed in the late 1990s and became popular in the early 2000s. 

At one stage during 2000-2010, MoM was the commonest bearing surface implanted, particularly in the young and active. 

But sales of MoM THR began to decline after concerns had begun to be expressed among orthopaedic professionals about revision rates and potential difficulties in carrying out revision operations. 

In 2012, public concern regarding the safety of MoM implants was increased by the broadcasting of the results of an investigation by the British Medical Journal and BBC Newsnight.

The court heard that since then, the implantation of MoM THRs stopped altogether, although some MoM hip resurfacings continue to be performed on patients, including the tennis player Andy Murray, for whom this is considered by surgeons to be the appropriate option. 

‘Loss and damage’

Three years after his operations, the pursuer underwent revision of his left sided implant. The right sided implant has not been revised.

The pursuer argued that he had suffered “loss and damage” as a consequence of the use of MoM THR in his 2009 operations. 

His case was based on section 2 of the Consumer Protection Act 1987, which imposes no-fault liability for damage caused by a defect in a product. 

The preliminary proof heard by the court was restricted to the question of whether certain propensities and risks inherent in MoM THR prostheses rendered the particular combination of components used in the pursuer’s operations defective within the meaning of the 1987 Act.  

The pursuer’s argument focused on the fact that surgeons had stopped recommending MoM THRs about three years after his operations, in the wake of concerns about the length of time the MoM hip replacement lasted before it required to be revised compared to alternative products using different materials; and a “higher risk” of an unsuccessful revision.

The judge found that the pursuer had established that there “may be a causal link” between the creation of metal debris from a MoM THR and periprosthetic damage, but “only in a minority of cases and in limited circumstances, including high levels of exposure, and not necessarily for reasons peculiar to MoM THRs”.

‘Entitled expectation’

But the pursuer had not proved that the THR components used in his operations were defective in relation to “entitled expectation” at the time when his prostheses were supplied.

In a written opinion, Lord Tyre said: “In my opinion, for the reasons set out in the preceding paragraphs, the pursuer has not proved, on balance of probabilities, at the time when his prostheses were supplied, either (a) that survivorship was worse for the Mitch/Accolade product than for existing alternative products that could have been implanted instead; or

(b) that use of the Mitch/Accolade product gave rise to an increased risk that revision surgery, in the event of its failure, would be unlikely to achieve as satisfactory an outcome as if the primary implant had been one of the existing alternatives.

“I therefore find that the pursuer has not proved, on balance of probabilities, that the entitled expectation in relation to the Mitch/Accolade product at the time of its supply to the pursuer was not met. It follows that he has not proved, on balance of probabilities, that there was a defect in the product so as to give rise to liability on the part of the defenders under the 1987 Act.”

However, he added: “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. 

“I have noted the view of Professors Breusch and Pandit [the consultant orthopaedic surgeons who gave expert evidence on behalf of the pursuer and defenders respectively], expressed in their joint statement, that ‘it is a consensus opinion now among orthopaedic surgeons that all large head MoM implants are associated with an increased risk of earlier failure than comparator non-MoM implants but most currently remain satisfactory under long term surveillance’.”

The case was the first such action in which a proof has been heard in the Scottish courts.

Although the proof was concerned with a specific combination of components produced by particular manufacturers, it is envisaged that this opinion will be of relevance to actions concerning MoM THRs more generally.