The unicompartmental knee implant UniSpacer (TM): Ten-year outcomes after treatment for medial tibio-femoral osteoarthritis

Background: UniSpacer (TM) type implants were part of the therapeutic armamentarium for medialtibio-femoral osteoarthritis before they were taken off the market in 2011. UniSpacer (TM) is a mobile interpositional self-centring implant that replicates the shape of the meniscus. It requires no bone cuts or component fixation. The objective of this follow-up note is to provide data on the 10-year outcomes in a cohort investigated previously in a study published in 2011. This study provides a re-evaluation of implant survival 5 years after the first analysis, as well as information on patient satisfaction and functional outcomes. Hypothesis: UniSpacer (TM) survival remains stable after 5 additional years and provides satisfactory functional outcomes. Material and methods: We included the same patients operated on from 2003 to 2009, namely, with 17 UniSpacer (TM) implants in 16 patients. The operative technique was the same in all patients. At last follow up, the patients attended a visit designed specifically to allow a clinical evaluation (IKS score, revision, forgotten implant) and new radiographic imaging of the treated knee. Results: Mean follow-up of this retrospective study of a prospective database was 118 +/- 25 months. Of the 17 implants, 9 (53%), in 8 patients, were still in place. Six (37.5%) patients underwent early revision arthroplasty (between 6 months and 4 years). One patient was lost to follow-up and another had died. The mean global IKS knee score was 76 +/- 15 and the mean IKS function score was 80 +/- 25. The global IKS score at last follow-up was 157 +/- 39. Mean range of flexion was 119 +/- 20 degrees Of the 8 patients (9 implants) who still had their implants at last follow-up, 5 (56%) reported forgetting their implant. No revisions were performed between 4 and 10 years of follow-up. Discussion: The ten-year survival was limited (53%). Clinical outcomes were satisfactory in the patients who still had their implants. The low cost and simplicity of insertion may make this implant a reasonable alternative for patients with contraindications to very major surgery. (C) 2021 Published by Elsevier Masson SAS.