title: Squeaking and microcracks in a delta-delta ceramic coupling: pin-on-disc study.
abstract: There is a rising concern about squeaking in ceramic-on-ceramic total hip arthroplasty (THA). In pin-on-disc testing of a delta-delta coupling, we reproduced squeaking and observed microcracks on worn surfaces. We used a pin-on-disc machine and made discs and pins by cutting delta ceramic to a diameter of 40 mm (D-D). Cross-linked polyethylene was used for a comparison disc (D-P). We performed the same test using another D-D coupling specimen to confirm reproducibility. Squeaking in the D-D specimen was reproduced in wet conditions, though it was not found in the D-P specimen. Fast Fourier transform analysis showed a peak frequency for squeaking of 2794 Hz. The noise occurred at about 6.6 km of sliding distance. Scanning electron microscopy revealed that the worn surface of the pin in D-D at 10.8 km of sliding distance had some microcracks. However, there was no obvious damage to the worn surface of the pin in D-P at the same sliding distance. We confirmed the reproducibility of these findings, obtaining similar results, including squeaking, from another D-D coupling specimen. Our findings show that squeaking may occur in THA using delta ceramic bearings even if implants are placed to avoid extra-articular impingement of the femoral neck. Although the clinical relevance of microcracks is unknown, they may affect long-term outcomes in THA using delta ceramic bearings.
authors.affiliation: Department of Orthopaedic Surgery, Kanazawa Medical University, Kahoku-gun, Japan. 66406kf@kanazawa-med.ac.jp.
authors.forename: Kiyokazu
authors.initials: K
authors.lastname: Fukui
authors.affiliation: Department of Orthopaedic Surgery, Kanazawa Medical University, Kahoku-gun, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kaneuji
authors.affiliation: Department of Orthopaedic Surgery, Kanazawa Medical University, Kahoku-gun, Japan.
authors.forename: Tadami
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Department of Mechanical Engineering, Kanazawa Institute of Technology, Hakusan, Ishikawa, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shintani
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D002516:Ceramics; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011475:Prosthesis Failure / Q000009:adverse effects; D013016:Sound
keywords: Delta ceramics; Microcracks; Squeaking; Total hip arthroplasty