Revision following patello-femoral arthoplasty

To describe the population of patients undergoing patello-femoral arthroplasty (PFA) revision and the reasons for which these implants are being revised. To compare this information with the observed failure patterns described in other national registries and with those seen for total knee replacement (TKR). Using data accessed from the National Joint Registry for England and Wales, we identified 4634 primary PFA implanted between 1 April 2003 and 30 June 2010. As of 1 July 2010, 195 PFAs had been revised. The epidemiology of PFA revision is described with specific emphasis upon the reasons for revision. The median age at revision was 61 years (145 F:50 M). Revision occurred at a median of 2.0 years following primary surgery. Sixty of the 98 centres (61%) performing PFA revisions undertook only one such procedure. The 195 revisions were undertaken by 140 different consultants. Unexplained pain was the reason for revision in 46% of cases where a reason was stated. Progression of tibio-femoral arthritis was seen in only 14% of cases. Undiagnosed pain remained the most common reason for revision irrespective of patient age and time to revision, and was twice as common for PFA revision when compared to a matched group of failed TKR (43% vs. 19%, P < 0.001). Unexplained pain is the principal indication for early revision of the failing PFA. The high proportion of revisions performed for unexplained pain raises questions about the adequacy of surgical selection for patients undergoing PFA. Retrospective comparative study, Level III.