Background: 

Spinal anesthesia provides several benefits for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA), but historically comes at the cost of slow and unpredictable return of lower-extremity motor function related to the use of long-acting local anesthetics. In this prospective, double-blinded, randomized clinical trial we sought to determine if an alternative local anesthetic, mepivacaine, would allow more consistent return of motor function compared with low-dose bupivacaine spinal anesthesia during primary THA and TKA.

Methods: 

This trial was conducted at a single academic institution. Prior to trial initiation an internal pilot study determined that 154 patients were required to achieve 80% power. Patients were randomized in a 1:1 fashion with use of advanced computerized stratification based on procedure, age group, sex, and body mass index. Following the surgical procedure, motor function was assessed every 15 minutes in the nonoperative lower extremity according to the Bromage scale and discontinued once Bromage 0 was achieved (spontaneous movement at hip, knee, and ankle).

Results: 

Return of lower-extremity function was more predictable in patients who received mepivacaine than in those who received low-dose bupivacaine. Among patients who received mepivacaine, 1% achieved motor function return beyond 5 hours compared with 11% of patients who received bupivacaine (p = 0.013). The mean time to return of lower-extremity motor function was 26 minutes quicker in patients who received mepivacaine (185 minutes; 95% confidence interval, 174 to 196 minutes) compared with low-dose bupivacaine (210 minutes; 95% confidence interval, 193 to 228 minutes) (p = 0.016). There were no significant differences in safety outcomes including pain scores, time to participation in physical therapy, incidence of orthostatic hypotension, urinary retention, or transient neurologic symptoms in patients receiving mepivacaine compared with low-dose bupivacaine.

Conclusions: 

In patients undergoing primary THA and TKA, spinal anesthesia with mepivacaine allowed more consistent return of lower-extremity motor function compared with low-dose bupivacaine, without a concomitant increase in complications potentially associated with spinal anesthetics. This is particularly of value in an era of short-stay and outpatient surgical procedures.

Level of Evidence: 

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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在全髋关节和全膝关节置换术中使用甲哌卡因与布比卡因脊髓麻醉相比，运动功能更可预测的回报：一项双盲，随机临床试验。

背景： 

脊柱麻醉为接受全髋关节置换术（THA）和全膝关节置换术（TKA）的患者提供了多种好处，但历史上是以与使用长效局麻药相关的下肢运动功能缓慢且不可预测的恢复为代价的。在这项前瞻性，双盲，随机临床试验中，我们试图确定在初次THA和TKA期间，与低剂量布比卡因脊柱麻醉相比，替代的局部麻醉药甲哌卡因能否使运动功能恢复更一致。

方法： 

该试验是在单个学术机构中进行的。在开始试验之前，一项内部先导研究确定需要154名患者达到80％的功率。根据手术程序，年龄组，性别和体重指数，采用先进的计算机分层方法，以1：1方式将患者随机分组。手术后，根据Bromage量表每15分钟对非手术性下肢运动功能进行评估，并在达到Bromage 0（髋，膝和踝关节自发运动）后停止运动功能。

结果： 

与接受小剂量布比卡因的患者相比，接受甲哌卡因的患者下肢功能的恢复更容易预测。在接受甲哌卡因的患者中，超过5小时的运动功能恢复率为1％，而接受布比卡因的患者为11％（p = 0.013）。与小剂量布比卡因（210分钟； 95％置信区间193）相比，接受甲哌卡因（185分钟； 95％置信区间为174至196分钟）的患者，下肢运动功能恢复的平均时间快26分钟。至228分钟）（p = 0.016）。安全性结果包括疼痛评分，参加物理治疗的时间，体位性低血压的发生率，尿incidence留，

结论： 

在接受原发性THA和TKA的患者中，与小剂量布比卡因相比，使用甲哌卡因进行脊柱麻醉可使下肢运动功能更一致地恢复，而不会伴随潜在地增加与脊髓麻醉药有关的并发症。这在短期住院和门诊手术时代特别有价值。

证据级别： 

治疗I级。有关证据水平的完整说明，请参见《作者说明》。