To answer your question, I do not believe it possible to entirely predict all real world failures of medical devices. The core problem of design controls is that they are created with what the designers or creators anticipate to occur once the product is moved to market. Real world performance of devices depends on a multitude of factors, many of which are out of the control of designers or are so niche that it may have not been a considered issue during the designing phase. Design controls are in place to minimize risk I would say, but not necessarily eliminate it. When you have a risky device like DePuy's hip implant, its important to ensure that your post market surveillance and validation processes are robust to prevent risk from occurring and responding to it efficiently if it were to occur.  DePuys major mistake was relying mostly on passive post market surveillance which relied on voluntary reporting from those experiencing issues. Instead, this post market surveillance should have been an active data backed process to accurately catch problems with the device earlier than later. I think fundamentally it is impossible to predict all instances in which a device can fail under real world usage. That being said, it is absolutely possible to develop design controls to detect and respond to issues that arise quickly and efficiently to prevent harm being done on a large scale to patients using the product. 

While it might be possible that not every real-world failure can be predicted or fixed with design controls, however in this case highlights how design controls are not effective unless there is a workplace culture willing to enforce integrity and commitment to proper design controls. According to the source you provided, the first lawsuit was issued in June of 2010, and the product was launched in 2003. The lawsuit also alleges that Johnson and Johnson knew about the failure rate much earlier than their recall, and quietly issued warnings to doctors about its failure rate while phasing the product out. While I agree with the earlier post that the post market surveillance fell way short of what it should have been, I think that the company's behavior in the wake of the discovery shows a lack of commitment to ensuring patient quality and safety, and is far more serious concern and likely culprit behind this product failure. 

I think that unforeseen circumstances can always occur no matter how in-depth of a plan someone has, it is difficult to predict every possible outcome and even if you have the best scientists available it is easy to miss something. So, having the design controls is just a way to decrease the likelihood of catastrophic reaction occurring, which is possibly what prevented other issues from happening. Similar to how certain medication is only helpful for some patients, it can be difficult to predict how everyone will respond to a product, so the best bet is to have a plan in case something does arise. I agree with the first response about how the company should not have relied on voluntary surveys because it can be hard for patients to depict problems and that means it is more likely that the issues that build up can go unnoticed, but it can be difficult to meet with everyone that has been given the replacement. Also, patients probably do not always have the time available to go in for regular checkups after, so even then it can be easy to miss. Recalls are common no matter what industry it is, so I think that if there are precautions that is better than completely allowing a company to produce a product that has no set of controls because that will lead to a far worse tragedy. 

The failure of the DePuy hip implant is probably due to not enough diversity in the testing population. Real world patients can vary widely in weight, height bone density and levels of physical activity can affect an implant's effectiveness over time. Another factor could be that the long-term biocompatibility testing may have not been sufficient. Even if the materials passed short termed safety tests, more long term exposure to metal debris over the years can cause undetected tissue damage that earlier studies wouldn't detect. To avoid this, I agree that for conclusive post market observation should be conducted as well as, to avoid risk, real life simulations that better reflect how implants will behave in everyday use. Besides post marketing, what else can be done during verification and validation testing to prevents an event like this from happening?

Everyone’s made great points about prediction limits and company oversight. Another major gap is that verification and validation don’t really reflect real-life patient diversity. The DePuy implants may have passed lab tests, but they didn’t consider how factors like bone density, weight, or activity levels affect wear over time.

To improve this, verification could use digital twin simulations or accelerated wear testing that mimic years of movement and different patient profiles. It might also help to run diverse pre-market trials or even “stress-test” sessions where engineers and clinicians try to find weak spots before approval.

We’ll never predict every failure, but adding more realistic, varied testing could make recalls a lot less likely. Do you think making diversity-based simulations mandatory would slow innovation too much, or is it worth it for safety?