Clinical Outcomes of Offset Stem Couplers with or without Cone Augmentation in Revision Total Knee Arthroplasty.

Introduction Intramedullary stems are often required in patients undergoing revision total knee arthroplasty (rTKA) to achieve stable fixation. Significant bone loss may require the addition of a metal cone to maximize fixation and osteointegration. The purpose of this study was to investigate clinical outcomes in rTKA using different fixation techniques. Methods We conducted a single-institution retrospective review of all patients who received a tibial and femoral stem during rTKA between August 2011 and July 2021. Patients were separated into three cohorts based on fixation construct: press-fit stem with an offset coupler (OS), fully cemented straight (CS) stem, and press-fit straight (PFS) stem. A sub analysis of patients who received tibial cone augmentation was also conducted. Results A total of 358 patients who underwent rTKA were included in this study, of which 102 (28.5%) had a minimum two-year follow-up and 25 (7.0%) had a minimum five-year follow-up. In the primary analysis, 194 patients were included in the OS cohort, 72 in the CS cohort, and 92 in the PFS cohort. When stem type alone was considered, there was no significant difference in re-revision rate (p=0.431) between cohorts. Sub analysis of patients who received augmentation with a tibial cone demonstrated that OS implants led to significantly higher rates of re-revision compared to the other two stem types (OS: 18.2% vs CS: 2.1% vs PFS: 11.1%; p=0.037). Conclusion The findings of the present analysis demonstrate that fully cemented stems and cones in rTKA may provide more reliable long-term outcomes compared to press-fit stems with offset couplers.