https://doi.org/10.1177/1120700020964976 HIP International 2020, Vol. 30(2S) 59–65 © The Author(s) 2020 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1120700020964976 journals.sagepub.com/home/hpi HIP HIP International Introduction Dislocation is a troublesome complication of total hip arthroplasty (THA) with reported incidence ranging from 0.2% to 7% after primary THA and from 10% to 25% after revision THA. 1 Instability is a leading cause of revision, accounting for 17.3% of all revisions among several popu- lations. 2 The risk of dislocation after THA is multi-facto- rial and includes surgeon-related factors as well as patient-related factors. 3,4 Surgeon-related factors are: sur- gical approach, restoration of hip biomechanics (off-set, leg-length and centre of rotation), component positioning, soft-tissue handling and repair. Patient-related factors are: age, indication for the procedure, previous operation on the hip, comorbidities (including neuromuscular diseases, cognitive dysfunction, spine diseases). Developments in implant design has assisted surgeons to reduce the risk of dislocation. The use of larger femoral heads has been associated with reduced incidence of dislo- cation both in primary and revision THA, 5 whereas con- strained liners are currently considered a salvage procedure Modular dual-mobility cups using ceramic liners: an original solution for selected indications? Rocco D’Apolito, Guido Bandettini, Filippo Maria Piana Jacquot and Luigi Zagra Abstract Background: Dual mobility (DM) has been shown to improve stability both in primary and revision total hip arthroplasty (THA) and is increasingly used in patients at high risk of dislocation and in the treatment of THA instability. The introduction of modular liners has helped to overcome some of the limitations of monoblock DM cups. In this context, the use of a ceramic liner would avoid the conventional cobalt-chromium liner in the titanium shell, which can be problematic in some situations. The aim of this paper is to report the outcomes of a consecutive series of patients undergoing revision THA using a modular DM cup with a ceramic liner instead of the conventional metal one, and to clarify the rationale for this currently “off-label” use. Patients and methods: This is a retrospective series of patients who received this new DM bearing in a single institution. Patients were followed up clinically and radiologically at 1 month, 3 months, 6 months and yearly thereafter. Results: 5 patients received the ceramic liner in the study period (2014–2019). The indications were instability or high risk of dislocation in ceramic liner fracture and ARMD with soft tissue damage after MoM THA. The mean age at surgery was 74 (63–82) years, the mean follow-up was 36 (12–72) months. No dislocation occurred, and no adverse events related to the implant were recorded. Conclusions: The use of a ceramic liner in a modular DM cup offers several advantages in selected patients, and the results of our cohort are encouraging. However, caution is needed in introducing this new bearing because knowledge is currently limited. Further studies on a larger number of patients and with longer follow-ups are needed to confirm these findings and before widespread use of the device. Keywords Ceramic liner, cup revision, dislocation, dual mobility, instability, modular cup, total hip arthroplasty Date received: 20 May 2020; accepted: 05 August 2020 IRCCS Istituto Ortopedico Galeazzi, Hip Department, Milan, Italy Corresponding author: Rocco D’Apolito, IRCCS Istituto Ortopedico Galeazzi, Hip Department, Via Riccardo Galeazzi 4, Milan, 20161, Italy. Email: roccodapolito@hotmail.it 964976HPI 0 0 10.1177/1120700020964976HIP InternationalD’Apolito et al. research-article 2020 Original Research Article