Causes of revision following Oxford phase 3 unicompartmental knee arthroplasty

Revision of unicompartmental knee arthroplasty (UKA) is relatively rare, but there is concern that the minimally invasive approach might result in more complications and a higher rate of revision. Current data regarding the revision of UKA using the Oxford phase 3 prosthesis are confined to a few reviews of single-institution experience. The purpose of this study was to provide an evidence-based summarisation of the revision of UKA with a pooled analysis of the reported cases.

A systematic review of published studies that evaluated the causes that required further surgical intervention after UKA using the Oxford phase 3 prosthesis was performed. A structured literature review of multiple databases referenced articles from 1998 to 2012. The revision rates between Asian population and western population were compared.

A total of 2,683 patients (3,138 knees) from 17 published studies were assessed. The median age of the patients was 62.5 (range 32-93) years. The median follow-up period was 5.6 (range 0.1-11) years. Postoperative revision was necessary in 146 knees with a pooled percentage of 4.6 %. Bearing dislocation was found to be the single most important predisposing cause of revision, with a pooled percentage of 1.5 % (47/3,138 knees). The rate of bearing dislocation was significantly higher in Asian population than that in western population (p < 0.001).

Mobile bearing UKA seems to be less appropriate for the Asian population as extreme knee flexion is required for cultural purposes.