title: Case reports: fractures of threaded cups: rare complications of a well-established implant.
abstract: The use of cementless threaded cups in THA is a well-established treatment. Fractures of the cups are rare complications recorded in individual cases with material defects being discussed as the primary cause. We analyzed three cases of fractured cups. Although all three cups were well fixed to existing bone, we observed deficient osseous backing dorsocranially and abrasion particles. There were no signs of femoroacetabular impingement or infection. The cups showed corrosion debris. Scanning electron microscopic investigations showed characteristics of fretting and fretting-related corrosion. We concluded the fractures occurred because of fretting combined with inadequate bony support leading to fatigue of the material and subsequent fracture.
authors.affiliation: Department of Orthopaedics, Trauma and Reconstructive Surgery, Humboldt University of Berlin, Schumannstrasse 20/21, Charité, 10117, Berlin, Germany. arnd.hoburg@charite.de
authors.forename: Arnd T
authors.initials: AT
authors.lastname: Hoburg
authors.forename: Manav
authors.initials: M
authors.lastname: Mehta
authors.forename: Stephan
authors.initials: S
authors.lastname: Tohtz
authors.forename: Carsten
authors.initials: C
authors.lastname: Perka
mesh_terms: D000328:Adult; D001168:Arthritis / Q000000981:diagnostic imaging / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012086:Reoperation; D013314:Stress, Mechanical; D013499:Surface Properties