Unicompartmental Arthroplasty with the Oxford Knee. Buy the book here.
This chapter is available from Goodfellow Publishers as a PDF.
Unicompartmental Arthroplasty with the Oxford Knee. Buy the book here.
This chapter is available from Goodfellow Publishers as a PDF.
Introduction
In this chapter we describe the common modes of failure of the OUKA and suggest ways of dealing with them. We also discuss why they occur and how they can be prevented.
Complications occur more commonly in the hands of learners than in those of the experienced surgeons whose reports are published in the literature. As a result, the incidence of complications is lower in published cohort series compared to national registers
In Table 11.1 we show the incidence of the various different complications in two different series, the NJR and our own series out to 15 years.
Table 11.1 Reasons for reoperation in the designer series and NJR based on Patient Time Incident Rate (PTIR).
|
Indication for re-operation / revision |
Designer Series: Phase 3, at mean 10 years |
NJR Data: at 10 years |
|
Progression of arthritis in the lateral compartment |
2.4 % |
2.6 % |
|
Bearing dislocation |
0.7 % |
0.1 % |
|
Unexplained pain |
0.7 % |
1.9 % |
|
Infection |
0.6 % |
0.5 % |
|
Aseptic loosening |
0.2 % |
3.6 % |
|
Fracture |
|
0.2 % |
|
PFJ problem |
|
|
|
Other |
0.6 % |
3.5 % |
In the long term, the commonest cause of failure is progression of arthritis in the lateral compartment although the incidence is low. In the NJR, there is a much higher incidence of revision for pain or loosening than in the designer series. This is likely to be, at least in part, because of misinterpretation of tibial radiolucency. Inexperienced surgeons often consider the common stable radiolucency to be a source of pain or indicative of loosening when the evidence suggests it is not. The dislocation rate of 0.1% in the NJR is surprisingly low, perhaps because surgeons do not consider treatment of a dislocation to be a revision. There are no failures because of patellofemoral joint problems or wear in either series.
