The Oxford medial unicompartmental knee replacement has been shown to provide good long-tern results in numerous studies with survivorship at 10 years ranging from 82% to 100%. This prospective study describes the survival of 265 Oxford unicompartmental knee replacements implanted in one centre from 1995-2009. 8 were lost to follow up. 40 of the 265 knees were revised. For operation performed from1995-1999 the risk of revision at 5 years was 10%, operations from 2000-2004 the risk of revision was 15% and from 2005-2009 the risk of revision at 5 years was 36%.

This study demonstrates that since 2005 there has been a significant increase in early failure of the Oxford unicompartmental knee at this institution and discusses the possible reasons for this.