The end to end process for the design, manufacture and distribution of hip replacement parts is lengthy and fairly complex. Many different companies, individuals and institutions are involved, each making their own contribution to what is a fairly lengthy supply chain.
In addition, it can take many years from the point at which the product designers create the initial blueprint for a hip replacement part, to the point that the product is first implanted in a patient.
Against this backdrop it is perhaps not surprising that on some, thankfully rare occasions, a small number of hip replacement parts are introduced to the market that subsequently prove to be either defective or have a higher risk of failure than was initially anticipated.
Regulators, manufacturers and all individual professionals involved in the end to end supply chain are committed to producing and distributing only products that are safe. Everyone has a vested interest in doing all that is possible to achieve a 100% successful outcome.
A comprehensive suite of quality checks and controls are integrated into the supply chain right from design through to the introduction of any hip replacement implants live on the market. These controls are intended to ensure that only products that meet strict quality standards will ever reach hospitals, clinics or operating theatres.
However, we all live and operate in the real world, and competing pressures and priorities are inevitably introduced, and the risk of simple human error can never be wholly removed.
In any supply chain, and that for hip replacement parts is no different, there will always be a residual risk remaining that some defective products may reach the market, despite the rigorous checks and control frameworks that are in operation.
Inherent Design Defects - pushing the envelope
Healthcare and joint manufacturing organizations share a common objective to design new products that break new ground. There is a constant drive to develop hip replacement parts and systems that:
Almost inevitably, as pioneering hip implant designs are formulated, tested, manufactured and rolled out, some products may fall short of either expected performance or minimum prescribed safety standards. Any hip implants falling into this category will most likely need to be recalled from the market.
Thankfully, the skills, capabilities and commitment to excellence of all parties involved in the industry are such that the incidence of such failure is relatively rare.
Every supply chain breaks down into a number of distinct process steps that are broadly carried out in sequence.
Up front is the design piece, where a good outcome will be that hip replacement parts are designed that will be safe in use.
'Safe' needs to be interpreted based on the notes below in that it does not mean 100% risk free. In reality Safe means that a product will perform within an expected tolerance, but that some residual risks remain - effectively risks that are inherent to the product, even when it has been manufactured fully in accordance with the specified design.
A manufacturing defect occurs when the manufacturing process and activities result in the creation of a product that fails to match the original specified design.
Defective Warnings & Instructions
All hip implant components carry some inherent risk, even when they have been manufactured and distributed precisely as was intended. This applies regardless of the materials used: metal; ceramic; polyethylene.
Hip replacement parts are essentially man-made, foreign objects that are introduced into the body to substitute for what was originally a natural joint - on this basis, all replacement hip parts will carry some risk in use.
Manufacturers and distributors have a responsibility to ensure that the residual risks inherent to the finished product are clearly, accurately and completely described in the warning and instruction literature that accompanies the product.
Orthopedic surgeons and other professionals need to be able to understand and rely on the written warnings and instructions supplied with hip prostheses in order that the inherent risks of the product can be explained to the patient prior to surgery, enabling fully informed decisions to be made.
If the warnings and / or instructions provided with hip replacement parts are inadequate, contain errors or are misleading then it is likely that the product will need to be recalled from the market.
510(k) Premarket Approval Process
In most medically advanced countries regulators require the manufacturers of hip replacement parts to carry out clinical trials to evidence that products are safe before introducing them to the market. In some countries, including the U.S., there has existed some flexibility in the premarket product approval process, effectively a fast-track route to market, avoiding the need for extensive clinical trials.
In order to qualify for this '510(k) process' (FDA parlance), the manufacturer needs to demonstrate that the new product is 'substantially equivalent' to a product that is already on the market, and which has therefore been subject to appropriate clinical trials and has received prior regulatory approval.
In practice, some products which allegedly have novel design characteristics, have been approved through the 510(k) channel, when in fact they should have been subject to full clinical trials.
The vast majority of hip replacement parts are well designed, correctly manufactured in accordance with that design, and supplied with appropriate warning and instruction documentation.
Very rarely, some defective hip implants products do make it to market which subsequently need to be recalled. A subset of these recalled products may have caused injury or harm to some patients.