4.1 This document provides guidance for a range of assessments and evaluations to aid in preclinical research and device development of hard-on-hard total and resurfacing hip joint replacements used for the repair of musculoskeletal disorders.

4.2 The user is encouraged to use appropriate ASTM or ISO standards to conduct the physical, chemical, mechanical, biocompatibility, and preclinical tests on alloy fabricated forms, ceramic material samples, device components, or devices before assessment in an in vitro model.

4.3 Studies to support regulatory submissions should conform to appropriate regulatory requirements and guidelines for the development of medical devices.

4.4 Assessments with physical, chemical, mechanical, biocompatibility, and preclinical tests on hard-on-hard femoral and acetabular components are not necessarily predictive of human results and therefore should be interpreted cautiously with respect to potential applicability to clinical conditions. Referenced metal-on-metal or ceramic-on-ceramic hip joint replacement publications can be found in the References section at the end of this guide for further review.

1.1 This guide covers materials and design recommendations and general test methods for the mechanical and preclinical assessment of implantable devices with hard-on-hard articulations intended to replace a hip joint. The provided guidance is intended to encompass both total hip joint replacements as well as resurfacing hip joint replacement (RS). There has been long-term clinical experience with metal-on-metal articulating components manufactured from cobalt-28chromium-6molybdenum (Co-28Cr-6Mo) alloy (as specified in ASTM F75, F799, or F1537) and ceramic-on-ceramic articulating components manufactured from alumina-based ceramics (as specified in ISO 6474-1 or ISO 6474-2). This guide has been created based on the current understanding derived from those clinical histories. Implant articulating components manufactured from other metallic alloys, ceramics, or with coated or elementally modified articulating surfaces could also be evaluated with this guide. However, such materials that do not have a history of clinical use may present different risks.

1.2 This guide applies to the acetabular and femoral articulating components of hard-on-hard hip joint replacements. Acetabular components can be monobloc, or a modular component with a separate cup and liner. As stated above, articulating components have been made from Co-28Cr-6Mo for a metal-on-metal bearing; and alumina-based ceramics for a ceramic-on-ceramic bearing. Cups of modular acetabular components have to date been made from Ti-6Al-4V (as specified in ASTM F136 or F1472, or ISO 5832-3) or Co-28Cr-6Mo. The shell is considered part of the acetabular component. Acetabular components may have an external coating and/or porous structure intended for uncemented, press-fit or biological fixation, or for use with bone cement.

1.3 This guide is a summary of available specifications, test methods, practices, and guides from published standards or the scientific literature. Their clinical relevance is unproven. Most of the methods do not have an established precision and bias; therefore, their repeatability and reproducibility have not been established. As the clinical relevance of these methods have not been established, consequently, most do not have performance requirements. This document does not require that all the listed methodologies are always necessary to evaluate these implant systems provided justification for not using each unused method is provided. This document does not intend to prevent the use of new methodologies as they are developed.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.