Abstract
Introduction
Patients-reported outcome measures (PROMs) have been reported as the important methods to evaluate clinical outcomes in total knee arthroplasty (TKA). The patient satisfaction score in Knee Society Score (KSS-2011) has been used in the recent literatures. Patient satisfaction was subjective parameter, and would be affected by multiple factors including psychological factors and physical conditions at not only affected joint but also elsewhere in the body. The question was raised regarding the consistency of patient satisfaction score in KSS-2011 to other PROMs.
The purpose of this study was to investigate the correlation of patient satisfaction in KSS-2011 to other categories in KSS-2011 and to other PROMs including Forgotten Joint Score (FJS-12), EuroQol-5 Dimensions (EQ-5D) and 25-questions in Geriatric Locomotive Function Scale (GLFS-25).
Material & Method
83 patients over 65 years old with osteoarthritic knees were involved in this study. All patients underwent CR-TKAs (Persona CRR). The means and ranges of demographics were as follows: age; 74.5 years old (65–89), Hip-Knee-Ankle (HKA) angle; 12.4 (−6.2–22.5) in varus. We asked patients to fulfill the questionnaire including KSS-2011, FJS-12, EQ-5D and GLFS-25 at 1-year postoperative follow-up visit. KSS-2011 consisted of 4 categories of questions; patient satisfaction (PS), symptoms, patient expectations (PE), functional activities (FA).
We evaluated the correlation of PS to other PROMs using simple linear regression analyses (p<0.001).
Results
The means and standard deviations of 1-year postoperative scores were as follows: PS; 28.5 ± 7.0, symptoms; 19.1 ± 4.3, PE; 11.2 ± 2.9, FA; 71.5 ± 16.6, FJS-12; 51.5 ± 18.6, EQ5D; 0.69 ± 0.10, GLFS-25; 25.7 ± 16.9. PSs were moderately positively correlated to other categories in KSS-2011(correlation coefficient (r): symptoms; 0.69, PE; 0.73, FA; 0.69). PSs were positively correlated to both FJS-12 and EQ5D (r: FJS-12; 0.72, EQ-5D; 0.67) and negatively correlated to GLFS-25(r; −0.74).
Discussions
Patient satisfaction score positively correlated to the symptoms, patient expectation and functional activities in KSS-2011 with moderately high correlation coefficient. This meant the better pain relief and functional outcome improved patient satisfaction. Although there had be reported preoperative higher expectation would lead to poor patient satisfaction postoperatively, we interestingly found positive correlation between patient satisfaction and expectation at 1 year after TKA. Patient with the higher satisfaction tended to expect more in the future, on the other hand, unsatisfied patient with residual pain and/or poor function would resign themselves to the present status and reduced their expectation in our patient population. We have found patient satisfaction score in KSS-2011 significantly correlated to FJS-12 and GLFS-25 with strong correlation coefficient. This meant patient satisfaction could be considered consist to other PROMS in relatively younger patient with better functional status in this study.
Conclusion
The patient satisfaction score in KSS-2011 was found to be consistent with moderately high correlations coefficient to other categories in KSS-2011 and other PROMs including FJS-12, EQ-5D, GLFS-25 at 1 year after (CR)-TKA.
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