This document specifies requirements for single layer thermally sprayed hydroxyapatite coatings applied to metallic surgical implants.

These requirements are intended to describe properties of the materials and to communicate these between organizations. These requirements are not written with the objective of replacing a company's internal operational and assessment requirements although they could be used as such.

NOTE 1 For thin coatings with a thickness of less than 50 °m, some of the test methods described in this document might be difficult to apply without modification.

NOTE 2 The requirements of the hydroxyapatite layer of dual-layer coatings (consisting of a lower layer of metallic coating and an upper layer of hydroxyapatite coating) can follow this document; however, testing methods referred to in this document cannot be applied to dual layer coatings. If this document is taken in reference for the requirements of the hydroxyapatite layer of dual layer coatings, a rationale on how the single-layer tested coupons are representative of the dual-layer coated implant might be considered necessary.

This document does not cover coatings made from glasses, glass ceramics, alpha- and beta-tricalcium phosphate, biphasic calcium phosphate or other forms of calcium phosphate.

NOTE 3 While the requirements in this document are intended to be used as specifications of a thermally sprayed coating of hydroxyapatite, it might be necessary to establish routine control procedures specifying control tests and their time intervals to make sure the characteristics of the coating stay within specified limits.

NOTE 4 This document was developed with a focus on plasma sprayed coating of hydroxyapatite. It might also be used to characterize other thermally sprayed coatings of hydroxyapatite. However, thermally sprayed coatings that do not have a history of clinical use might present different risks and might need additional characterizations beyond those identified in this document.