2023 ISAKOS Biennial Congress ePoster
Comparison Of Outcomes Of Primary TKA With Revision UKA To TKA - A Propensity Matched Study
Ravi Teja Rudraraju, MD, Hyderabad, Telangana INDIA
Harbeer Ahedi, PhD Biomedical Sciences, Sydney, New South Wales AUSTRALIA
Brett A. Fritsch, MBBS BSc(Med), FRACS, FAOrthA, Hunters Hill, NSW AUSTRALIA
David A. Parker, MBBS, BMedSc, FRACS, Sydney, NSW AUSTRALIA
Myles R. J. Coolican, FRACS, Sydney, NSW AUSTRALIA
Sydney Orthopaedic Research Institute, Sydney, New South Wales, AUSTRALIA
FDA Status Not Applicable
Summary
Our study has showed that re-revision rates, survivorship and outcomes in primary UKA patients are better than previously thought and similar to primary TKA patients.
ePosters will be available shortly before Congress
Abstract
Introduction
Joint replacement registries have shown patients undergoing revision of UKA to TKA to have Oxford scores, satisfaction scores and implant survivorship similar to those of revision TKR patients and less satisfactory than primary TKA. We hypothesised that our UKA revision to TKA Oxford scores, patient satisfaction and implant survivorship would be about the same as our primary TKA patients.
Method
Patients who presented to our clinic and underwent revision of a UKA to TKA were included in the study group and compared with primary TKA patients from the same period matched for age, BMI and sex. This was a retrospective analysis of prospectively collected data. We compared Oxford and knee satisfaction scores, VR12 and re-revision rates in for both groups with data collected preoperatively and at 1 year, 2-4 yrs. and five years after surgery. Characteristics of the population were summarised as means and standard deviations (SD) or as frequencies and percentages.
Results
Included in the study were 78 patients with a UKA revision and 90 patients were propensity matched TKA patients. The average age (71.0 yrs. vs 71.4 yrs., p=0.70), gender distribution (Females: 52% vs 57%, 0.47) and mean body mass index (BMI) (31.4 kg/m2 vs 30.4 kg/m2, p=0.38) was similar in both groups. Re-revision rate in UKA group was 4.4% with a 10 year survivorship of 93.44% and at 15 years 90.12%. Before surgery the Oxford score in both groups was similar (24.5 vs 25.9, p=0.82). One year after surgery, there was improvement in the score in both groups with TKA doing slightly better (38.4 vs 41.8, p<0005). However, long term Oxford score for both groups showed no difference (41.2 vs 40.1, p=0.80). In addition, at the end of one year of follow up patient satisfaction scores and VR 12 scores for both groups were similar.
Discussion
Despite the commonly held belief that a good UKA has better function than a good TKA, the past 15 years has seen a gradual reduction in the proportion of UKA to TKA. Whilst this is likely in part due to a higher revision rate as portrayed by national registries, a further contributing factor is data to suggest that the inevitable failure of a UKA will be followed by a less satisfied patient after TKA with a higher chance of revision. Our data runs contrary to this suggestion.
Conclusions
Combining registry data shows an overall UKA implant survivorship at 15 years of 81.8% with New Zealand at 81.1% , Australian 78% and the UK registry at 14 years is 83.1%. Our study has showed that re-revision rates, survivorship and outcomes in primary UKA patients are better than previously thought and similar to primary TKA patients.