Abstract
Introduction
Patient self-reported outcome scales have recently been used to evaluate total knee arthroplasty (TKA) outcomes. Many follow-up studies have been conducted on patients undergoing TKA; however, they have mostly reported outcomes after unilateral TKA. We believe that a longitudinal study after bilateral TKA will be more useful in evaluating the quality of life (QOL) of such patients.
Objectives
The objective of this study was to longitudinally evaluate QOL using the Japanese Knee Osteoarthritis Measure (JKOM). Objective outcomes were assessed using the Knee Society Score (KSS) and the Timed Up and Go test (TUG) for more than 5 years after bilateral TKA. Furthermore, QOL and objective outcomes were compared between younger (age ≤ 80 years at the final follow-up point) and older (age > 80 years) age groups.
Methods
In total, 109 patients underwent two-staged bilateral TKAs for varus knee osteoarthritis at our clinic between October 2006 and March 2013. Of these patients, 78 were evaluated preoperatively (Pre) and at 1, 3 and 5 years or more (average, 6.7 years; range, 5–10 years) after bilateral TKAs using JKOM, KSS and TUG. The average patient age at the time of the first and the contralateral TKAs was 73.3 (range, 61–85) years and 74.0 (range, 62–85) years, respectively. The average patient age at the final follow-up point among younger (36 patients) and older (42 patients) age groups was 75.8 (range, 67–80) years and 84.7 (range: 81–92) years, respectively. The outcomes at each evaluation point were compared using Steel–Dwass test. A comparison of the JKOM scores and objective outcomes between the younger and older age groups was performed using Mann–Whitney U-test. P values < 0.05 were considered significant.
Results
A significant improvement in the JKOM score was observed between ‘Pre’ and ‘1 year after bilateral TKA’; the improvement was maintained until the final follow-up point. All four subscales in JKOM showed the same improvement as JKOM itself. Furthermore, significant improvements in the total KSS, knee and function scores were observed between ‘Pre’ and ‘1 year after bilateral TKA’; the improvement was maintained until the final follow-up point. A significant improvement in the TUG scores was observed between ‘Pre’ and ‘1 year after bilateral TKA’; although the improvement was maintained for 3 years, there was a small but significant deterioration at the final follow-up point. Although the average age difference between the two groups was 8.9 years, no significant differences were found in the JKOM and objective outcome scores between the younger and older age groups.
Conclusions
This is the first longitudinal mid-term follow-up study to evaluate QOL after bilateral TKAs. The JKOM and objective outcome scores reached a plateau 1 year after bilateral TKA, and the improvement was maintained for an average of 6.7 years; however, TUG scores showed a small deterioration at the final follow-up point. The improvement in the JKOM and objective outcome scores maintained by the older age group was equivalent to that by the younger one.
