Abstract
Summary Statement
This paper is the first to compare the results of unicompartmental to total knee arthroplasty revision surgery between cases with explained pain and cases with unexplained pain. Revision surgery for unexplained pain usually results in a less favourable outcome.
Introduction
Although it is suggested in literature that results of UKA to TKA revision surgery improve when the mechanism of failure is understood, a comparative study regarding this topic is lacking.
Methods
All cases of revision surgery in two hospitals in the Netherlands were listed retrospectively. Fifteen cases with unexplained pain were listed in group A and 15 cases with a cause for pain in group B. Oxford knee scores (OKS), visual analogue scores (VAS) and patient satisfaction one year after revision surgery were compared.
Results
OKS improved from 19 to 25 within group A and from 23 to 38 within group B. VAS improved from 7, 7 to 5, 4 within group A and from 7, 4 to 1, 7 within group B. The difference in outcome between both groups is statistically significant, p=0,022 for OKS and p=0,002 for VAS. Subgroup analysis in group A, performed in order to define a patient factor that predicts outcome of revision surgery in case of unexplained pain, showed no preoperative differences between both subgroups.
Discussion
These results are important to properly inform patients about what to expect of revision surgery, highlighting that UKA to TKA revision surgery for unexplained pain generally results in a less favourable outcome.
