Abstract
This study presents the intraoperative findings of a cohort of 201 cases of failed Unicompartmental knee arthroplasties (UKA) from the Trent Wales arthroplasty audit group (TWAAG) register from 1990 to 2008. The main objectives of the study were to determine the common modes of failure and trends in implant systems used using sex and age matching criteria.
Results demonstrate the varying reasons for revision, use of augmentation and surgical preference in revision system. Results include survival rates and revision rates of UKA from the Trent Wales arthroplasty audit group. The average patient age at revision surgery with the average times from primary UKA to total knee arthroplasty are demonstrated. Aseptic loosening was the commonest reason for revision in both younger and older age groups, closely followed by Polyethylene wear in the younger age group versus progression of osteoarthritis in the other compartments in the older age group. The commonest implant used was Oxford unicompartmental knee system at primary surgery with the PFC implant used in almost 50% of all cases that were revised. This study demonstrates the survival rate of UKAs to be significantly higher in female patients and in those patients with primary UKAs at a younger age. The trends in revision systems have changed over the years. In the early years, over 50% used the PFC knee systems, compared to the latter eight years where the majority used revision knee systems, (e.g. LCCK and Legion). This trend is due to increased availability and ease of use of revision systems. The commonest site of augmentation was for tibial bone defects. Approximately 50% of all augmented cases required tibial blocks or wedges.
Although current thinking suggests most UKAs can be revised to a primary total knee system without difficulty, a significant proportion required revision implant systems with associated implications.
The abstracts were prepared by Mr Matt Costa and Mr Ben Ollivere. Correspondence should be addressed to Mr Costa at Clinical Sciences Research Institute, University of Warwick, Clifford Bridge Road, Coventry CV2 2DX, UK.
