Is it Possible to Treat Insert Dislocation With a Fixed Insert Tibial Component After Primary Oxford Phase 3 Mobile Unicompartmental Knee Arthroplasty?

Abstract

Background: The aim of this study was to investigate the clinical and radiologic outcomes of patients who underwent the revision surgery of tibial component replacement using fix-insert in the cases of Oxford phase 3 medial unicompartmental knee arthroplasty with insert dislocation after initial insert replacement. Materials and Methods: Nine patients who experienced insert dislocation after insert replacement and who underwent partial replacement revision (tibial component revision) were included in this study. Demographic data and complications of these patients were evaluated. Clinical outcomes were determined through Knee Society Score and Functional Knee Society Score. Results: Insert redislocation happened in 11 of 17 patients whose insert was already replaced after initial insert dislocation. Among 11 patients, 2 patients underwent primer and revision total knee replacement revision surgery due to gap inequality and medial collateral ligament deficiency. In the other 9 patients, partial tibal component revision was performed. The mean follow-up time for the patients was 44.4 (21 to 76) months. The mean Knee Society Score/Functional Knee Society Score scores were 80.1 (72 to 95)/78.6 (70 to 90) and 79.5 (72 to 90)/77.5 (68 to 90) at the final follow-up after partial revision and before the insert dislocation, respectively. There was no decline in clinical scores and no revision was required in the mid-term follow-up. Conclusions: In this study, we found that there was no worsening in the clinical scores of the patients in the mid-term and no revision was required following the treatment of redislocation through tibial component revision. It was concluded that partial revision treatment with a fixed insert tibial component in the case of insert redislocation does not increase morbidity and could be an ideal treatment option. However, this conclusion should be further supported by multicenter studies along with the high number of cases. Level of Evidence: Level IV—retrospective case-control study.