Survivorship of the C-Stem in cement-in-cement revision hip arthroplasty

Introduction: Cement-in-cement (CiC) is a well-established technique in revision hip arthroplasty. It involves cementing a new femoral stem into an existing intact cement mantle. It is less invasive than the conventional technique of removing well-fixed cement. This study evaluates the clinical and radiological outcomes of the C-Stem in CiC revision hip arthroplasty at the design centre. Methods: A retrospective analysis was conducted using a prospectively maintained database of CiC revision hip arthroplasties performed between July 2015 and 2023. Inclusion criteria included patients undergoing CiC femoral revision with a C-Stem and have a minimum of 1 year follow-up. Patients with a disrupted cement mantle, infection at index surgery, or less than 1 year of follow-up were excluded. Data on indications, complications, radiographs and survivorship were analysed. Kaplan–Meier survival analysis was performed with revision for any cause as the endpoint. Results: There were 102 cases, of which 78 had at least 1 year of clinical and radiological follow-up. The average patient age was 71 years (47–90). The mean follow-up was 41 (25–72) months. The 3 most common reasons for revision surgery were cup loosening (60%), dislocation (16%) and stem loosening (11%). Following revision arthroplasty using the CiC technique, there were a total of 11.8% stem revisions. Kaplan-Meier survival analysis was 86% (95% confidence interval 76–96) at 8 years for all-cause stem revisions. There were no re-revisions of the femoral stem for aseptic loosening. The majority of cases (93%) maintained their preoperative Barrack grading. Conclusions: This largest single study demonstrates favourable medium-term implant survival with the C-Stem in CiC revision hip arthroplasty. This technique remains viable in carefully selected revision cases since it is associated with a much lower complication and risk profile. Further studies with longer follow-up and functional outcome scores are warranted.