2021 ISAKOS Biennial Congress ePoster
Minimal Clinically Important Difference (MCID) In WOMAC Score And Factors Related To Achievement Of WOMAC Score MCID After Medial Opening Wedge High Tibial Osteotomy For Knee Osteoarthritis
Dong-Chul Park, MD, Seoul, South Korea KOREA, REPUBLIC OF
Man-Soo Kim, MD, PhD, Seoul KOREA, REPUBLIC OF
Yong Gyu Sung, MD, Seoul KOREA, REPUBLIC OF
Jae Jung Kim, MD, Seoul KOREA, REPUBLIC OF
Yong In, MD, PhD, Seoul KOREA, REPUBLIC OF
Seoul St. Mary's Hospital, Seoul, KOREA, REPUBLIC OF
FDA Status Cleared
Summary
The MCID for WOMAC scores in patients who underwent MOWHTO were 4.2 points for pain, 1.9 points for stiffness, 10.1 points for function, and 16.1 points for total WOMAC score. Lower preoperative WOMAC score, severe OA, and under- or over-correction were related to failure to achieve MCID
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Abstract
Introduction
Many approaches have been used to determine minimal clinically important differences (MCID) in total knee arthroplasty patients, but MCID in outcome measures after medial opening wedge high tibial osteotomy (MOWHTO) for the treatment of medial compartment knee osteoarthritis (OA) have not been reported. The purpose of this study was to define MCID for Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores after MOWHTO and to identify risk factors for not achieving MCID.
Methods
Among patients with medial compartment knee OA who underwent MOWHTO, 174 patients who were followed-up for 2 years were included in the study. MCID of WOMACs was measured using the anchor-based method with a 15-item anchor questionnaire. MCID were calculated as the difference in WOMAC scores between the minimal improvement group and no change group. Preoperative OA severity was measured by Kellgren-Lawrence grade, and the acceptable range of the postoperative weight bearing line (WBL) ratio was defined as 50 - 70%. Patients were divided into two groups based on whether MCID was achieved, and then factors related to the failure to achieve MCID were analyzed using multivariate logistic regression analysis.
Results
MCID in WOMAC scores were 4.2 points for the pain score, 1.9 points for the stiffness score, 10.1 points for the function score, and 16.1 points for the total score. 116 (66.7%), 99 (56.9%), 127 (73.0%) and 128 (73.6%) patients achieved the MCID for WOMAC pain, stiffness, function, and total scores after MOWHTO. The odds of not achieving the MCID in WOMAC total score were 1.09 times greater (95% CI: 1.05 - 1.13, p < 0.001) in individuals with a low preoperative WOMAC total score (cut-off values: 10.5 for pain, 3.5 for stiffness, 34.5 for function, and 51.0 for total score), 11.77 times greater (95% CI: 3.68 – 37.70, p < 0.001) in patients with K-L grade 4 OA compared to K-L grades 2 or 3 OA, and 8.39 times greater (95% CI: 2.98 – 23.63, p < 0.001) in patients with under- or over-correction.
Conclusions
The MCID for WOMAC scores in patients who underwent MOWHTO were 4.2 points for pain, 1.9 points for stiffness, 10.1 points for function, and 16.1 points for total WOMAC score. Lower preoperative WOMAC score, severe OA, and under- or over-correction were related to failure to achieve MCID.