BACKGROUND Persistent postsurgical pain after total knee arthroplasty is a common problem and a major reason for patient dissatisfaction. This secondary analysis aimed to investigate the effects of anesthesia (spinal vs. general) and tourniquet use on persistent pain after total knee arthroplasty. METHODS In this secondary analysis of a previously presented parallel, single-center, randomized trial, 404 patients scheduled for total knee arthroplasty were randomized to spinal versus general anesthesia and no-tourniquet versus tourniquet groups. Patients assessed pain using the Brief Pain Inventory-short form preoperatively and 3 and 12 months postoperatively. The prespecified main outcome was the change in "average pain" measured with numerical 0 to 10 rating scale 1 yr postoperatively. The threshold for clinical importance between groups was set to 1.0. RESULTS The change in average pain scores 1 yr postoperatively did not differ between the spinal and general anesthesia groups (-2.6 [SD 2.5] vs. -2.3 [SD 2.5], respectively; mean difference, -0.4; 95% CI, -0.9 to 0.1; P = 0.150). The no-tourniquet group reported a smaller decrease in the average pain scores than the tourniquet group (-2.1 [SD 2.7] vs. -2.8 [SD 2.3]; mean difference, 0.6; 95% CI, 0.1 to 1.1; P = 0.012). After 1 yr, the scores concerning the mean of four pain severity variables (numerical rating scale) decreased more in the spinal than in the general anesthesia group (-2.3 [SD 2.2] vs. -1.8 [SD 2.1]; mean difference, -0.5; 95% CI, -0.9 to -0.05; P = 0.029) and less in the no-tourniquet than in the tourniquet group (-1.7 [SD 2.3] vs. -2.3 [SD 2.0]; mean difference, 0.6; 95% CI, 0.2 to 1.0; P = 0.005). None of the differences in pain scores reached the threshold for clinical importance. CONCLUSIONS The type of anesthesia (spinal vs. general) or tourniquet use has no clinically important effect on persistent postsurgical pain after total knee arthroplasty. EDITOR’S PERSPECTIVE

中文翻译：

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全膝关节置换术后的麻醉方法、止血带的使用和持续的术后疼痛：随机试验的预设二级分析。

背景技术全膝关节置换术后持续的术后疼痛是一个常见问题，也是患者不满意的主要原因。本次分析旨在研究麻醉（脊柱与全身）和止血带的使用对全膝关节置换术后持续疼痛的影响。方法 在对先前提出的平行、单中心、随机试验的二次分析中，404 名计划进行全膝关节置换术的患者随机分为脊髓麻醉组与全身麻醉组以及无止血带组与止血带组。患者在术前和术后 3 个月和 12 个月使用简短疼痛量表评估疼痛。预设的主要结果是术后 1 年用 0 到 10 的数字量表测量的“平均疼痛”的变化。组间临床重要性的阈值设置为 1.0。结果 腰麻组和全身麻醉组术后 1 年平均疼痛评分的变化没有差异（分别为 -2.6 [SD 2.5] 与 -2.3 [SD 2.5]；平均差异，-0.4；95% CI，-0.9到 0.1；P = 0.150）。与止血带组相比，无止血带组报告的平均疼痛评分下降幅度较小（-2.1 [SD 2.7] vs. -2.8 [SD 2.3]；平均差异，0.6；95% CI，0.1 至 1.1；P = 0.012 ）。1 年后，与全身麻醉组相比，脊柱中四个疼痛严重程度变量（数值评定量表）的平均值下降更多（-2.3 [SD 2.2] vs. -1.8 [SD 2.1]；平均差异，- 0.5；95% CI，-0.9 至 -0.05；P = 0.029）且无止血带组低于止血带组（-1.7 [SD 2.3] vs. -2.3 [SD 2.0]；平均差，0.6；95% CI，0.2 到 1.0；P = 0.005）。疼痛评分的差异均未达到临床重要性的阈值。结论 麻醉类型（脊柱与全身）或止血带的使用对全膝关节置换术后持续性术后疼痛没有临床意义的影响。编辑的观点