4 Key Elements of Design Controls

While we already know that design controls are vital to the development of every orthopedic device, the integrated and complex process can leave even seasoned professionals with questions.

Several years ago, John Gagliardi, President of MidWest Process Innovation LLC, authored a series on design controls that we believe is still relevant today. We dug into the archives to pull out four key elements of design controls as they relate to process, with the hope that you can lean on this primer when you need a quick refresher.


FDA requires that each orthopedic manufacturer establish and maintain procedures to make certain that the design requirements relating to a device are appropriate and address the intended use of the device, including the needs of the user and patient, and that packaging and shipping containers are designed and constructed to protect the device during processing, storage, handling and distribution. Design inputs, sometimes referred to as the requirements phase, is the starting point of understanding internal and external customer requirements.

These requirements establish a basis for performing subsequent design tasks and validate the entire device for its intended use, so developing a solid foundation of requirements is the most important design controls activity.

The device’s intended use should be defined in the input stage, and it should be specific and functionally accurate. The input stage is also the time for risk management, when device manufacturers should review recall data, competitor product issues and other resources to determine hazards that can be mitigated through design.

It’s important to note that user needs are the basis for design inputs, but are not design inputs themselves. Because user requirements can be vague (e.g., “must be portable”), a concept document may be the starting point for development but it does not fulfill the requirements of the design input phase, which needs exact measurements and specifications.

Once the concept of the new device design is established, the design input requirements can be developed. The design input defines the following:

  • Device performance
  • Safety and reliability characteristics
  • Environmental limits
  • Physical attributes
  • Compatibility with other devices
  • Applicable standards
  • Regulatory requirements
  • Packaging specifications
  • Labeling

Design input requirements fall into three categories: functional requirements (what the device does), performance requirements (how much or how well the device must perform) and interface requirements (characteristics critical to compatibility with external systems).


The design process is controlled and driven by a cross-functional group of individuals, so the review of data and progress of the design project is important to organize and orchestrate the various stage gates. These design reviews are part of a formal process intended to provide a systematic assessment of design results, including device, production and support process designs.

The formal design review will ultimately determine whether the project is ready to move on to the next stage of development or not. Basic requirements for a design review include the following:

  • Each manufacturer shall establish and maintain procedures to ensure that formal documented reviews of the design results are planned and conducted at appropriate stages of the device’s design development.
  • The procedures shall ensure that participants at each design review include representatives of all functions concerned with the design stage being reviewed, plus an individual who does not have direct responsibility for the design stage being reviewed, as well as any specialists needed.
  • The individual(s) performing the review shall be documented in the Design History File (DHF).

The main function of the reviews is to evaluate or confirm the solutions that the design team offers. Then, things like material choice or manufacturing methods are discussed, followed by issues related to verification, validation and the transfer of the design into manufacturing. While several meetings, iterations and evaluations take place during the design process, it is important to document significant issues and their resolutions using design reviews as a vehicle for compliance.

A formal design review process consistent with quality system requirements should include:

  • Evaluation of the design (including identification of concerns, issues and potential problems)
  • Resolution of concerns
  • Implementation of corrective actions

The procedure should include strategic and tactical linkages with the quality management system as well as post-production implications having to do with a redesign.


Design verification is the confirmation that the design output meets the design input requirements, including risk analysis. The design validation process involves establishing by objective evidence that device specifications conform with user needs and the intended use(s) of the medical device. For the best results and data accuracy, design verification should be achieved with test equipment calibrated and controlled according to quality system requirements. Verification and validation can also be done according to a written protocol. The protocol should include defined conditions for the testing and should be approved before use.

Test protocols evolve throughout the validation period for a new device. As the protocol changes, the designers and other verification personnel carefully annotate the updates, technical comments about deviations or other events that are happening during the testing phase.

Design changes start to be realized as inputs to the design are approved. All design changes should be accounted for and documented in the DHF. Design changes can be made after commercialization of the device, and should be documented, reverified and revalidated.


Design controls require that each orthopedic device manufacturer establish and maintain procedures to ensure that the device design is correctly translated into production specifications. The transfer process must be a part of the design plan.

FDA’s 21 CFR part 820 does not specify the practices that must be used for design transfer, because it is applied to a wide variety of devices and manufacturing systems. Instead, the code establishes a framework for transfer and any changes to a design.

The framework provides orthopedic manufacturers with the flexibility to develop design controls that comply with the regulations but are also appropriate for their own design and development processes. Everyone is expected to define, document and implement design transfer procedures and other quality system procedures, and all changes must be accounted for during the design process to maintain compliance.

The Quality System Regulation also requires that the DHF shall contain or reference the documentation necessary to demonstrate that the design followed the approved design plan and the requirements.

Manufacturers should initiate communication between manufacturing and design personnel early in the development phases and continue throughout the product’s lifecycle. It’s also important for development groups to ensure that production specifications are well understood and effectively implemented by the manufacturing team. The process of summarizing knowledge about the device into production specifications is important to establish the device’s quality throughout the lifecycle of design controls as well as post-commercialization.

The transfer of knowledge in the form of documentation from product development to the manufacturing process should be a well-orchestrated process resulting in the issuance of the Device Master Record (DMR) as part of the design output, with the DHF as the basis for the DMR.

Design controls are an interrelated set of practices and procedures that are not only incorporated into the design and development process, but used by companies to operate on a day-to-day basis and a platform for planning and carrying out an FDA inspection. Therefore, adhering to design controls best practices is imperative for all orthopedic device manufacturers.

John Gagliardi
has had success over 45+ years in the medical device and pharmaceutical industries because of his practical approach to process-orientation and business. He has been actively involved in research and development, quality assurance, training, operations, process architecture, FDA inspections and regulatory affairs. Mr. Gagliardi specializes in building systems in a compliant and business-ready manner.

Heather Tunstall is an ORTHOWORLD Contributing Editor.