Revision surgery for failed unicompartmental knee replacement: technical aspects and clinical outcome

The aims of this study were to determine the complexity of surgery required to revise failed unicompartmental knee replacements and to evaluate the outcome following revision. Between 2000 and 2009, 494 cemented Oxford phase 3 medial unicompartmental knee replacements were implanted, with 24 (4.9%) requiring revision (mean age: 63.5 years; 58% male). Mean time to revision was 3.0 years. All cases were revised to a cemented total knee replacement, with primary components used in 67% and revision components in 33%. At a mean follow-up of 3.2 years the median Oxford knee score was 333% with one knee requiring re-revision (5-year survival 933%). Most failed unicompartmental knee replacements could be revised without the need for stemmed implants, augmentation, or bone allograft. When bone loss occured it was commonly on the tibial side. Good functional outcome for the revised unicompartmental knee replacement was achieved and was comparable to primary knee replacement.