Nishitani Kohei, Yamamoto Yosuke, Furu Moritoshi, Kuriyama Shinichi, Nakamura Shinichiro, Ito Hiromu, Fukuhara Shunichi, Matsuda Shuichi
Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-Cho, Sakyo, Kyoto, 606-8507, Japan.
Department of Healthcare Epidemiology, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-Cho, Sakyo, Kyoto, 606-8507, Japan.
J Orthop Sci. 2019 Nov;24(6):1053-1057. doi: 10.1016/j.jos.2019.09.001. Epub 2019 Sep 19.
The new Knee Society Score (2011KSS) has been used to evaluate post-operative outcomes after total knee arthroplasty (TKA). However, there is no minimum clinically important difference (MCID) for 2011KSS. The purpose of this study is to define MCID of 2011KSS after TKA.
Patients who underwent primary TKA for primary knee osteoarthritis between April 2012 and December 2016 were included in the study. The Japanese version of 2011KSS and original Knee Society Score (OKSS) were recorded preoperatively and at one-year postoperatively. With improvement in pain score of OKSS as an anchor, an anchor-based approach was used to identify the MCID of 2011KSS. The improvement in pain of OKSS was classified into 5 categories. The MCID was determined using a linear regression analysis of delta 2011KSS against improvement in the category of pain in OKSS. The MCID for 2011KSS expectation was not calculated because the items of pre- and post-operative questionnaires were different.
Five hundred and twenty-two cases were enrolled (age: 74.8 ± 7.3 years, female: 80.0%). After 1-year follow-up, 344 TKAs were finally included (age: 74.6 ± 7.1 years, female: 77.9%). Linear regression analyses showed that MCID for 2011KSS was 1.9 (95% confidential interval (CI): 1.3-2.5) in symptom, 2.2 (95%CI: 1.4-2.9) in satisfaction, and 4.1 (95%CI: 2.5-5.7) in functional activities.
MCID for 2011KSS was successfully calculated. These MCID values make the 2011KSS a more efficient tool for evaluating the physical activities of the populations of patients undergoing TKA. These MCID values can also be used to calculate sample size to evaluate the power of a study in designing clinical studies.
新的膝关节协会评分（2011KSS）已用于评估全膝关节置换术（TKA）后的术后结果。然而，2011KSS尚无最小临床重要差异（MCID）。本研究的目的是确定TKA后2011KSS的MCID。
纳入2012年4月至2016年12月期间因原发性膝关节骨关节炎接受初次TKA的患者。术前和术后1年记录2011KSS的日语版本和原始膝关节协会评分（OKSS）。以OKSS疼痛评分的改善为锚点，采用基于锚点的方法确定2011KSS的MCID。OKSS的疼痛改善分为5类。通过对2011KSS差值与OKSS疼痛类别改善进行线性回归分析来确定MCID。由于术前和术后问卷项目不同，未计算2011KSS期望的MCID。
共纳入522例（年龄：74.8±7.3岁，女性：80.0%）。1年随访后，最终纳入344例TKA（年龄：74.6±7.1岁，女性：77.9%）。线性回归分析显示，2011KSS在症状方面的MCID为1.9（95%置信区间（CI）：1.3 - 2.5），在满意度方面为2.2（95%CI：1.4 - 2.9），在功能活动方面为4.1（95%CI：2.5 - 5.7）。
成功计算出2011KSS的MCID。这些MCID值使2011KSS成为评估TKA患者群体身体活动的更有效工具。这些MCID值还可用于计算样本量，以评估设计临床研究时研究的效能。
