title: New couplings, old problems: Is there a role for ceramic-on-metal hip arthroplasty?
abstract: Ceramic-on-metal (CoM) total hip arthroplasty (THA) theoretically combines both the advantages of ceramic-on-ceramic (CoC) and metal-on-metal (MoM) bearings: negligible rupture risk of the liner with a limited ion release. As primary endpoint, we asked whether serum cobalt, chromium and molybdenum concentrations in 20 CoM-THA patients at an average of 3-years follow-up were higher than those measured in the pre-operative population and correlate with clinical/radiological parameters. As secondary endpoint, we wanted to verify whether ion levels in CoM-THA patients were different from those obtained in a similar cohort of 29 MoM-THA patients at the same average follow-up. Ion values were measured by atomic absorption spectrometry. Functional outcome was assessed with Harris Hip Score and UCLA scale. Presence of radiographic radiolucencies around the implant, and acetabular inclination angle were evaluated. Chromium and cobalt levels in CoM-THA patients were significantly higher (p < 0.001) at 3-years follow-up than before surgery. Molybdenum concentrations were not significantly different (p = 0.45). No signs of implant loosening were recorded. Functional outcome was excellent with HHS and UCLA scale rising from 50 and 3.6 pre-operatively to 90.8 and 6.3, respectively at 3-years follow-up (p < 0.001). Chromium serum levels were significantly lower in CoM-THA than in MoM-THA group (p = 0.02) while cobalt values, even if lower, did not reach statistically significance (p = 0.054). Our results show that CoM-THA patients achieve excellent clinical outcome with a limited chromium release at 3-years follow-up.
authors: Department I of Orthopaedics and Traumatology, Rizzoli Orthopaedic Institute, Bologna, Italy.|Department of Biomedical and Neuromotor Sciences, Bologna University, Bologna, Italy.
authors: Matteo
authors: M
authors: Cadossi
authors: Department of Biomedical and Neuromotor Sciences, Bologna University, Bologna, Italy.
authors: Antonio
authors: A
authors: Mazzotti
authors: Department of Biomedical and Neuromotor Sciences, Bologna University, Bologna, Italy.|Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopaedic Institute, Bologna, Italy.
authors: Nicola
authors: N
authors: Baldini
authors: Department I of Orthopaedics and Traumatology, Rizzoli Orthopaedic Institute, Bologna, Italy.|Department of Biomedical and Neuromotor Sciences, Bologna University, Bologna, Italy.
authors: Sandro
authors: S
authors: Giannini
authors: Laboratory for Orthopaedic Pathophysiology and Regenerative Medicine, Rizzoli Orthopaedic Institute, Bologna, Italy.
authors: Lucia
authors: L
authors: Savarino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D002516:Ceramics; D002857:Chromium / Q000097:blood*; D003035:Cobalt / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D002857:Chromium; D003035:Cobalt
keywords: ceramic-on-metal coupling; chromium; cobalt; ion release; total hip arthroplasty