15 Years Experiences with Alumina-Ceramic Total Hip-Joint Endoprostheses. A Clinical, Histological and Tribological Analysis

Abstract

The clinical and tribological performance of 67 ceramic sockets was evaluated, implanted 1976 to 1979 without bone cement in alumina-on-alumina metal compound total hipjoint replacements.

8 sockets showed radiological signs of loosening, resulting in a survival probability of 83.85%(±5.4%) at a mean survival time of 144.7 months. Around all stable sockets a 1–2 mm wide radiolucent seam developed and remained constant in time. The surrounding tissues of stable sockets, removed due to stem failures, showed a replica of the ceramic surface grooves by a pseudosynovia or occasional fibrocartilage, but no bone ingrowth. Small amounts of ceramic debris corresponded well to low wear rates/year (socket:0.95 μm, head: 1.7 μm), calculated from tribological analysis of one alumina-pairing after 133 months of service. Early loosening appeared from 8 months on as concentric widening of the radiolucent seam to more than 10 mm, while late loosening was indicated from 25 or 80 months on by tilting into valgus position and migration of the socket. Enormous amounts of ceramic wear particles stored in macrophages were found in surrounding tissues, accompanied by chronic inflammation and bone resorption only in early loosening. Tribological analysis of one loose alumina-pairing showed design-related damage, inadequate ceramic density and thus increased abrasion of the components (socket:27.2 μm, head:40.9 μm/year). In conclusion, properly manufactured alumina-ceramic can meet the expectations for long-lasting articulating surfaces, provided correct position and stable condition of the implant. Cementfree ceramic socket stabilization is only achieved by a connective tissue interlayer to bone which is vulnerable by accumulation of ceramic wear particles.