BACKGROUND Several studies have investigated failure rates and magnitude of improvement in patient-reported outcome measures after microfracture surgery for focal chondral defects of the knee; however; what constitutes clinically significant improvement in this patient population is poorly understood. PURPOSE To (1) establish the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) thresholds for microfracture surgery including the time-dependent nature of these thresholds and (2) identify predictors of achieving the MCID and PASS in patients specifically undergoing microfracture of the knee. STUDY DESIGN Case series; Level of evidence, 4. METHODS A secure institutional cartilage preservation repository was queried for all patients who underwent microfracture between 2004 and 2017. The distribution method was used to calculate MCID thresholds for the International Knee Documentation Committee (IKDC) score and the Knee injury and Osteoarthritis Outcome Score (KOOS), whereas an anchor-based method was used for the PASS. Multivariate logistic regressions were constructed to determine predictors of achieving the MCID and PASS. RESULTS A total of 206 patients with a mean ± SD age of 33.7 ± 13.2 years and body mass index of 26.9 ± 5.3 kg/m2 were included. All thresholds for the MCID and PASS increased over time except for the MCID thresholds for the KOOS Sports and Symptoms subscales. The proportion of patients who achieved the MCID (6 months, 78.4%; 12 months, 83.9%; 24 months, 88.6%) and PASS (6 months, 67.7%; 12 months, 79.2%; 24 months, 76.1%) generally increased over time. Older age and larger lesion size were negative independent predictors of MCID achievement. Older age was also a negative predictor of the PASS, whereas male sex and higher preoperative KOOS Symptoms and Pain scores were positive independent predictors of the PASS. CONCLUSION The MCID and PASS thresholds for the IKDC and KOOS in patients undergoing microfracture of the knee are dynamic, with an increasing number of patients achieving the MCID over time. The percentage achieving the PASS increased between 6 and 12 months and then declined slightly at 24 months. Independent predictors of achieving the MCID were lesion size and age at surgery, whereas predictors of achieving the PASS included lesion size, male sex, and greater preoperative KOOS Symptoms and Pain scores.

中文翻译：

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定义膝关节微骨折的最小临床重要差异和患者可接受的症状状态：短期随访的心理分析。

背景技术一些研究调查了膝关节局灶性软骨缺损的微骨折手术后的失败率和患者报告的结局指标的改善幅度。然而; 对该患者群体的临床上显着改善的构成了解甚少。目的（1）建立微骨折手术的最小临床重要差异（MCID）和患者可接受的症状状态（PASS）阈值，包括这些阈值的时间依赖性；以及（2）具体确定患者中实现MCID和PASS的预测因子膝盖微骨折。研究设计案例系列；证据级别，第4级。方法对2004年至2017年间接受微骨折的所有患者，查询了一个安全的机构软骨保存库。分布方法用于计算国际膝关节文献委员会（IKDC）得分以及膝关节损伤和骨关节炎结果得分（KOOS）的MCID阈值，而PASS使用基于锚的方法。构建多元逻辑回归，以确定实现MCID和PASS的预测因子。结果共纳入206例患者，平均±SD年龄为33.7±13.2岁，体重指数为26.9±5.3 kg / m2。MCID和PASS的所有阈值都随时间增加，但KOOS运动和症状子量表的MCID阈值除外。达到MCID（6个月，78.4％; 12个月，83.9％; 24个月，88.6％）和PASS（6个月，67.7％; 12个月，79.2％; 24个月，76.1％）的患者比例普遍增加随着时间的推移。年龄较大和病变较大是MCID成就的阴性独立预测因子。年龄也是PASS的阴性预测因素，而男性，术前KOOS症状和疼痛评分较高是PASS的阳性独立预测因素。结论膝关节微骨折患者的IKDC和KOOS的MCID和PASS阈值是动态的，随着时间的推移，越来越多的患者达到MCID。通过PASS的百分比在6到12个月之间增加，然后在24个月时略有下降。实现MCID的独立预测因素是手术时的病变大小和年龄，而达到PASS的预测因素包括病变大小，男性，术前KOOS症状和疼痛评分更高。年龄也是PASS的阴性预测因素，而男性，术前KOOS症状和疼痛评分较高是PASS的阳性独立预测因素。结论膝关节微骨折患者的IKDC和KOOS的MCID和PASS阈值是动态的，随着时间的推移，越来越多的患者达到MCID。通过PASS的百分比在6到12个月之间增加，然后在24个月时略有下降。获得MCID的独立预测因素是手术时的病变大小和年龄，而达到PASS的预测因素包括病变大小，男性，术前KOOS症状和疼痛评分更高。年龄也是PASS的阴性预测因素，而男性，术前KOOS症状和疼痛评分较高是PASS的阳性独立预测因素。结论膝关节微骨折患者的IKDC和KOOS的MCID和PASS阈值是动态的，随着时间的推移，越来越多的患者达到MCID。通过PASS的百分比在6到12个月之间增加，然后在24个月时略有下降。获得MCID的独立预测因素是手术时的病变大小和年龄，而达到PASS的预测因素包括病变大小，男性，术前KOOS症状和疼痛评分更高。结论膝关节微骨折患者的IKDC和KOOS的MCID和PASS阈值是动态的，随着时间的推移，越来越多的患者达到MCID。通过PASS的百分比在6到12个月之间增加，然后在24个月时略有下降。获得MCID的独立预测因素是手术时的病变大小和年龄，而达到PASS的预测因素包括病变大小，男性，术前KOOS症状和疼痛评分更高。结论膝关节微骨折患者的IKDC和KOOS的MCID和PASS阈值是动态的，随着时间的推移，越来越多的患者达到MCID。通过PASS的百分比在6到12个月之间增加，然后在24个月时略有下降。获得MCID的独立预测因素是手术时的病变大小和年龄，而达到PASS的预测因素包括病变大小，男性，术前KOOS症状和疼痛评分更高。