TY - JOUR

T1 - Obese Patients Achieve Good Improvements in Patient-Reported Outcome Measures After Medial Unicompartmental Knee Arthroplasty Despite a Lower Preoperative Score

AU - Bagge, Anders

AU - Jensen, Christian B.

AU - Mikkelsen, Mette

AU - Gromov, Kirill

AU - Nielsen, Christian S.

AU - Troelsen, Anders

N1 - Publisher Copyright: © 2022 The Author(s)

PY - 2023

Y1 - 2023

N2 - Background: In this study, we examined the association between obesity and patient-reported outcome measures after medial unicompartmental knee arthroplasty (MUKA), assessed through score changes, Patient Acceptable Symptom State (PASS), and minimal important change (MIC). Second, the association between obesity and early readmissions was examined. Methods: A total of 450 MUKAs (mean body mass index [BMI] 30.3, range, 19.6-53.1), performed from February 2016 to December 2020, were grouped using BMI: <30, 30-34.9, and >34.9. Oxford Knee Score (OKS), Forgotten Joint Score (FJS), and Activity and Participation Questionnaire (APQ) were assessed preoperatively and at 3, 12, and 24 months, postoperatively. The 12-month PASS and MIC were also assessed, defining PASS as OKS = 30, MIC-OKS as change in OKS = 8, and MIC-FJS as change in FJS = 14. Results: No significant differences in OKS change were found between BMI groups. After 12 months, patients who had a BMI of 30-34.9 had lower change in FJS (estimate −8.1, 95% CI −14.9 to −1.4) and were less likely to reach PASS (odds ratio 0.4, 95% CI 0.2-0.7) as well as MIC-FJS (odds ratio 0.5, 95% CI 0.2-0.9). Both obese groups had lower change in APQ after 12 months. Differences in 90-day readmission rates were nonsignificant between groups. Conclusion: Our findings of no differences in OKS improvement between BMI groups and achieving MIC for BMI > 34.9 suggest good improvements in obese patients despite lower preoperative scores, supporting contemporary indications for MUKA. Lower APQ development and achievement of 12-month PASS may be used when addressing expectations of recovery.

AB - Background: In this study, we examined the association between obesity and patient-reported outcome measures after medial unicompartmental knee arthroplasty (MUKA), assessed through score changes, Patient Acceptable Symptom State (PASS), and minimal important change (MIC). Second, the association between obesity and early readmissions was examined. Methods: A total of 450 MUKAs (mean body mass index [BMI] 30.3, range, 19.6-53.1), performed from February 2016 to December 2020, were grouped using BMI: <30, 30-34.9, and >34.9. Oxford Knee Score (OKS), Forgotten Joint Score (FJS), and Activity and Participation Questionnaire (APQ) were assessed preoperatively and at 3, 12, and 24 months, postoperatively. The 12-month PASS and MIC were also assessed, defining PASS as OKS = 30, MIC-OKS as change in OKS = 8, and MIC-FJS as change in FJS = 14. Results: No significant differences in OKS change were found between BMI groups. After 12 months, patients who had a BMI of 30-34.9 had lower change in FJS (estimate −8.1, 95% CI −14.9 to −1.4) and were less likely to reach PASS (odds ratio 0.4, 95% CI 0.2-0.7) as well as MIC-FJS (odds ratio 0.5, 95% CI 0.2-0.9). Both obese groups had lower change in APQ after 12 months. Differences in 90-day readmission rates were nonsignificant between groups. Conclusion: Our findings of no differences in OKS improvement between BMI groups and achieving MIC for BMI > 34.9 suggest good improvements in obese patients despite lower preoperative scores, supporting contemporary indications for MUKA. Lower APQ development and achievement of 12-month PASS may be used when addressing expectations of recovery.

KW - minimal important change

KW - obesity

KW - Oxford Knee Score

KW - patient acceptable symptom state

KW - patient-reported outcome measures

KW - unicompartmental knee arthroplasty

U2 - 10.1016/j.arth.2022.09.002

DO - 10.1016/j.arth.2022.09.002

M3 - Journal article

C2 - 36096272

AN - SCOPUS:85138820146

VL - 38

SP - 252-258.e2

JO - Journal of Arthroplasty

JF - Journal of Arthroplasty

SN - 0883-5403

IS - 2

ER -