Survivorship of Isolated Head-Liner Exchange at Mean Follow up of Seven Years: A Comparison of Cemented and Uncemented Liners

Introduction: With improvements in femoral and acetabular fixation, there has arisen a need for more limited revision surgery in the form of isolated head-liner exchange. In many instances, despite a well-fixed cup, the locking mechanism has failed and one option has been to cement a new liner into the existing metalbacking. It has been shown that the cemented liners perform biomechanically the same or sometimes better than uncemented liners. The aim of this study is to evaluate the overall survivorship of a cohort of cemented and uncemented head-liner exchange revision surgeries.

Methods: We completed a retrospective study of all revision THAs performed for head-liner exchange at our institution. We stratified our cohort into two groups: cemented and uncemented polyethylene liners. Our primary outcome was survivorship of the exchanges for both cemented and uncemented liners. The survivorship of both groups was measured using Kaplan-Meier analysis.

Results: Between 2000 and 2018, 97 patients underwent head-liner exchange surgery (20 cemented and 77 uncemented liners). The mean follow-up was 7 years (range0.2-18 years). Twelve cases required revision (12.4%). One cemented liner failed for dislocation (1%), while seven (7.2%) uncemented liners failed for dislocation and four (4.1%) for non-dislocation causes.The survival analysis of all head-liner revisions was 66.9% at 18 years (95% CI 18.9-32.19%). There was no significant difference in revision rates between cemented and uncemented liners. There was, however, a positive trend toward improved survivorship in the cemented group at 85.7% (95% CI 12.1-52.3%) compared to 62.1% (95% CI 21.8-34.7%) in the uncemented group.

Conclusion: The present study shows no differences in survivorship between cemented and uncemented head-liner exchange. Cementing a liner into a pre-existing well-fixed metalbacked acetabular component is an excellent option for isolated head-liner exchange revision surgery.