The Interconnected Ancestral Network of Hip Arthroplasty Device Approval

Background: In the United States, the most overwhelming medical devices, including hip arthroplasty devices, are cleared for human use by demonstration of "substantial equivalence" to a predicate, previously approved marketed device. This study examined the predicate approval lineages of modern hip arthroplasty devices. Methods: The FDA 510(k) and premarket approval databases were searched to identify all approved hip arthroplasty devices since the database's inception in May 28, 1976. Ancestral predicate lineages were created using approval documentation, and FDA recall data were used to identify recalled devices. Results: Evaluating 2,118 hip arthroplasty devices approved from 1976 to 2020, we found that the number of descendant devices for each approved device varied from 0 to 242. Many descendant devices served as predicates for other devices, leading to frequent indirect connections of equivalency across a wide range of implants. Two hundred forty-six (11.6%) devices were recalled for various reasons, with 34 (1.6%) related to implant design. Evaluating the predicate lineage of 51 hip arthroplasty devices approved between May 1, 2019, and May 1, 2020, 32 of 51 (62.7%) devices were linked, directly or indirectly, to predicates which were recalled for design issues. Conclusions: The lineage of hip arthroplasty device predicates reflects a complex ancestral web of equivalency across a wide range of implants, although their material and design properties may be different. Several currently approved devices were approved on substantial equivalence claims to products that were subsequently recalled from the market for implant design issues. These findings present several policy considerations for regulators, physicians, and the medical device industry.