Emara AK, Peterson J, Piuzzi NS, Klika A, Rajaravivarma R, Higuera-Rueda C, Roy S. Effect of liner offset and inclination on cement retention strength of metal-in-metal acetabular constructs: A biomechanical study.
J Orthop Res 2021;
39:813-820. [PMID:
32678920 DOI:
10.1002/jor.24807]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/17/2020] [Accepted: 06/24/2020] [Indexed: 02/04/2023]
Abstract
Cementing metallic liners into well-fixed acetabular shells facilitates utilizing dual-mobility cups in revision total hip arthroplasty without shell replacement. The current biomechanical study investigated the effect of increasing cemented liner (a) inclination; and (b) offset on the cement retention strength measured as the lever-out moment at cement failure. Eighteen metallic liner prototypes were cemented into cluster-hole acetabular shells at variable inclinations (0°, 10°, and 20°) and offsets (0 and 10 mm) relative to the enclosing acetabular shell (6 groups; n = 3 constructs per group). The constructs were connected to a material testing frame, and lever-out failure moments were tested through an established protocol. Failure occurred at the liner-cement interface (18/18). There was no correlation between liner inclination and the lever-out failure moment (r = -0.327, P = .185). Liner offset demonstrated a strong negative correlation to mean lever-out failure moments (r = -0.788, P < .001). There was no significant difference between mean lever-out failure moments at variable liner inclinations, regardless of offset (P = .358). Greater liner offset was associated with diminished mean lever-out failure moments (P < .001). Compared with neutral (0° inclination, 0 mm offset), the maximum inclination and offset group had the lowest mean lever-out failure moment (P = .011). Cemented metal-in-metal constructs are significantly affected by the liner positioning. While a correlation between liner inclination and cement retention strength could not be asserted, cement retention strength is significantly diminished by increased liner offset.
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