The new Dutch hip classification system

The new Dutch hip classification system (NOV): Implications for industry, hospitals and clinical research

During the last few years governmental bodies and healthcare associations are introducing methods and guidelines for comparing medical devices. One intriguing classification system with far-reaching consequences for the industry, funding bodies, hospitals and clinical research has recently been introduced by the Dutch Orthopaedic Association (NOV). [1]

Having stated that its mission would be to work only with high-quality systems, [2] and to aim for maximum transparency for patients, the NOV’s Hip Task Force developed a classification system based on the NICE criteria. [3] For this, hip prostheses were divided into three categories:

  1. NOV 1A – Full acceptance and acknowledgement. A stem or cup with a mean revision rate of 10% or less at 10 years, with revision for any reason. Supporting data must come from any public national registers that are full members of International Society of Arthroplasty Registries (ISAR), [4] with ≥10 years’ follow-up on ≥500 implants or with an ODEP rating of 10A. [5]
  2. NOV 1B – Conditional benchmark. A stem or cup with a mean revision rate of 5% or less at 5 years, with revision for any reason. The data must follow the criteria for 1A, with ≥5 years’ follow-up on ≥500 implant or an ODEP rating of 5A or 7A.
  3. NOV 2 – New implants. Prostheses that do not meet or do not yet meet these above mentioned criteria may only be implanted in an approved research program.

The NOV published a full list of implants that meet the NOV 1A and 1B criteria.

While this method will undoubtedly provide clarity for patients and purchasers, the process will also have a series of consequences, at least in the Dutch market for now.

The Dutch Orthopaedic Association writes in their announcement letter that ‘innovation as a continuous process, which is mandatory for improving patient care, will be stimulated more with this quality classification. Since, all prostheses classified as NOV 2, will have prospective follow-up, to warrant patient safety.’ Although patient safety certainly is the most important goal, the big question is how the industry and healthcare providers will respond to this classification system on the short term.

Implications for the Medical Device Industry

The manufacturers providing hip implants that do not meet the 1A and 1B criteria are facing severe difficulties in continuing the supply of a, sometimes substantial, part of their hip implant product portfolio. Numerous hip implants currently sold in the Dutch market are now classified as NOV 2 because they fall into one of the following two groups:

  1. Hip implant without sufficient clinical data (≥5 years’ follow-up on ≥500 implant or an ODEP rating of 5A or 7A) in any of the 6 national arthroplasty Registers that have full ISAR member status: Many countries do not have any Registers or Orthopaedic Societies that are ‘full member’ of ISAR (e.g. France, Germany, Spain, Switzerland and USA). As a consequence, hip products that are primarily, or even exclusively, implanted in those countries will not be accepted by NOV and may only be implanted in the Netherlands as a part of a research programme (prospective follow-up).
  2. Recently launched hip implant: Any implants with less than 5 years clinical data available in the registries will not classify for the NOV 1B category.

We see two possible ways the industry is likely to respond to this:

  • Quickly start clinical studies for NOV 2 classified products that are currently in the Dutch market or soon to be launched in the Dutch market.
  • Convert current users of NOV 2 implants to another NOV 1A or 1B implant.

Implications for the Dutch hospitals

How will hospitals and orthopedic surgeons currently using category NOV 2 hip implants react? Two possible solutions to the NOV advice, would be to:

  • Try convincing the manufacturer to start a clinical study to prevent a short-term transition to another implant with related learning curve and training needs.
  • Start the procedure of selecting a new hip implant based on the new classification system.

Implications for Clinical Research in Europe

We expect that the implementation of these types of classification systems will spread throughout Europe and that there will be an impact on clinical research. Clinical study programmes will be constructed and developed with the express aim of meeting the criteria of local classification systems. The need for clinical research for new medical devices will be further integrated in the product development process.

Do you share the same opinion? Do you think that the new Dutch hip classification will spread to other European countries? What are the associated challenges for the hospitals and the manufacturers? Please feel free to leave a comment.



  1. Nederlandse Orthopaedische Vereniging. ‘s Hertogenbosch: NOV; 2013. [Accessed: 17 Feb 2013].
  2. Nederlandse Orthopaedische Vereniging. Strategisch Plan NOV. ‘s Hertogenbosch: NOV; 2012. [Accessed: 17 Feb 2013].
  3. National Institute for Health and Clinical Excellence. Guidance on the Selection of Prostheses for Primary Total Hip Replacement. NICE technology appraisal guidance 2. London: NICE, 2000.
  4. International Society of Arthroplasty Registries. Directory. ISAR; [Accessed: 17 Feb 2013].
  5. NHS Supply Chain. Orthopaedic Data Evaluation Panel. [Accessed: 17 Feb 2013].


About Wesley Portegies

Wesley has over 10 years' experience as a marketing manager in the medical industry. He has successfully launched several products in the medical device market and has a great passion for sales and marketing.
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