Medium to long-term results of the UNIX uncemented unicompartmental knee replacement

Abstract

Introduction: We report the first non-designer study of the Unix uncemented unicompartmental knee prosthesis.

Materials and methods: Eighty-five consecutive UKRs were carried out with sixty-five available for follow-up. Oxford Knee Scores, WOMAC questionnaire and radiological assessment were completed.

Results: The mean Oxford Knee Score was thirty-eight and WOMAC Score was twenty. Overall Kaplan Meier survival estimate is 76% (95% confidence interval 60%-97%) at 12years and 88% (95% confidence interval 76-100%) with aseptic loosening as the endpoint. Radiographic assessment showed lysis in the tibia in 6% of patients with no lysis evident around the central fin.

Discussion: Survivorship is comparable to other published series of UKRs. We suggest the central fin design is key to dissipating large forces throughout the proximal tibia, resulting in low levels of tibial loosening. Level of evidence IV.

Keywords: Radiolucent lines; Tibial loosening; Unicompartmental knee replacement; Unix.