The optimal analgesia for total knee arthroplasty (TKA) requires excellent analgesia while preserving muscle strength. This study aimed to determine the hypothesis that continuous adductor canal block (CACB) combined with the distal interspace between the popliteal artery and the posterior capsule of the knee (IPACK) block could effectively alleviate the pain of the posterior knee, decrease opioids consumption, and promote early recovery and discharge.
Patients undergoing unilateral, primary TKA were allocated into group CACB+SHAM (receiving CACB plus sham block) or group CACB+IPACK (receiving CACB plus IPACK block). The primary outcome was cumulative opioid consumption. Secondary outcomes included the incidence of postoperative pain originated from the posterior knee, visual analogue scale (VAS) score, range of motion, ambulation distance, and satisfaction for pain management.
The incidence of moderate-severe pain of the posterior knee was lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours (17.1% vs. 42.8%; p = 0.019), 8 hours (11.4% vs. 45.7%; p = 0.001), and 24 hours (11.4% vs. 34.3%; p = 0.046) after TKA. The VAS scores of the posterior knee were lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours [2 (2) vs. 3 (2-4); p = 0.000], 8 hours [1 (1, 2) vs. 3 (2-4); p = 0.001], and 24 hours [1(0-2) vs. 2 (1-4); p = 0.002] after TKA. The overall VAS scores were lower in group CACB+IPACK than that of the group CACB+SHAM at 4 hours [3 (2, 3) vs. 3 (3, 4); p = 0.013] and 8 hours [2 (2, 3) vs. 3 (2-4); p = 0.032] at rest and 4 hours [3 (3, 4) vs. 4 (4, 5); p = 0.001], 8 hours [3 (2-4) vs. 4 (3-5); p = 0.000], 24 hours [2 (2, 3) vs. 3 (2-4); p = 0.001] during active flexion after TKA. The range of motion (59.11 ± 3.90 vs. 53.83 ± 5.86; p = 0.000) and ambulation distance (44.60 ± 4.87 vs. 40.83 ± 6.65; p = 0.009) were superior in group CACB+IPACK than that of the group CACB+SHAM in postoperative day 1. The satisfaction for pain management was higher in group CACB+IPACK than that of the group CACB+SHAM [9 (8, 9) vs. 8 (7-9); p = 0.024]. There was no difference in term of cumulative opioids consumption between group CACB+IPACK and group CACB+SHAM [120(84-135) vs. 120(75-135); p = 0.835].
The combination of CACB and distal IPACK block could decrease the incidences of moderate-severe posterior knee pain, improve the postoperative pain over the first 24 hours after TKA, as well as promoting recovery of motor function. However, the opioids consumption was not decreased by adding distal IPACK to CACB.
This study was registered at Chinese Clinical Trial Registry ( ChiCTR2200059139 ; registration date: 26/04/2022; enrollment date: 16/11/2020; http://www.chictr.org.cn ).

To compare the analgesia effect and clinical rehabilitation between continuous adductor canal block (ACB) and single shot ACB in total knee arthroplasty (TKA)．.
Between October 2016 and February 2017, 60 patients with severe knee osteoarthritis undergoing primary unilateral TKA were prospectively recruited in the study. All the patients were randomly allocated into 2 groups and received ultrasound-guided continuous ACB (group A, n=30) or single shot ACB (group B, n=30), respectively. There was no significant difference in gender, age, body mass index, nationality, American Society of Anesthesiology (ASA) grading, and preoperative knee range of motion and quadriceps strength between 2 groups ( P>0.05). After operation, the tourniquet time, postoperative drainage volume, hospitalization time, and adverse events in 2 groups were recorded. Visual analogue scale (VAS) scores at rest and during activity, the quadriceps strength, the knee range of motion, and the time of 90° knee flexion in 2 groups were also recorded and compared.
There was no significant difference in tourniquet time, postoperative drainage volume, and incidence of adverse events between 2 groups ( P>0.05). But the hospitalization time was significant shorter in group A than in group B ( P<0.05). VAS scores at rest and during activity were lower in group A than in group B, with significant differences in VAS score at rest after 12 hours and in VAS score during activity after 8 hours between 2 groups ( P<0.05). The quadriceps strength was higher in group A than in group B, with significant difference at 24, 48, and 72 hours ( P<0.05). The knee range of motion was significantly better in group A than in group B at 24, 48, 72 hours and on discharge ( P<0.05). The time of 90° knee flexion was significantly shorter in group A than in group B ( t=-2.951, P=0.016). There were 4 patients in group A and 7 patients in group B requiring meperidine hydrochloride (50 mg/time) within 24 hours, and 3 patients in group A and 7 patients in group B at 24 to 48 hours, and 1 patient in group A and 3 patients in group B at 48 to 72 hours. Effusion in the catheter site occurred in 2 cases of group A, but no catheter extrusion occurred.
Continuous ACB is superior in analgesia both at rest and during activity and opioid consumption compared with single shot ACB after TKA. And the quadriceps strength could be reserved better in continuous ACB group, which can perform benefits in early rehabilitation.
探讨多模式镇痛下置管持续收肌管阻滞（adductor canal block，ACB）与单次注射 ACB 对人工全膝关节置换术（total knee arthroplasty，TKA）后镇痛及早期康复的影响。.
2016 年 10 月—2017 年 2 月，将 60 例因重度退行性骨关节炎拟行初次单膝 TKA 且符合选择标准的患者纳入研究，随机分为置管持续 ACB 组（A 组）和单次注射 ACB 组（B 组），每组 30 例。两组患者性别、年龄、体质量指数、民族、美国麻醉医师协会（ASA）分级以及术前膝关节活动度、股四头肌肌力等一般资料比较，差异均无统计学意义（ P>0.05），具有可比性。记录两组术中使用止血带时间、术后引流量、术后住院时间、盐酸哌替啶使用情况、不良反应事件发生情况。术后行静息及活动时疼痛视觉模拟评分（VAS），采用徒手肌力法评定股四头肌肌力，测量膝关节活动度并记录首次屈膝达 90° 时间。.
A 组术中使用止血带时间、术后引流量、不良反应发生率与 B 组比较，差异均无统计学意义（ P>0.05）；但 A 组术后住院时间较 B 组明显缩短（ P<0.05）。术后各时间点 A 组 VAS 评分均低于 B 组，其中术后 12 h 后静息 VAS 评分及 8 h 后活动 VAS 评分与 B 组比较，差异均有统计学意义（ P<0.05）。术后各时间点 A 组股四头肌肌力均优于 B 组，其中术后 24、48、72 h 组间比较差异有统计学意义（ P<0.05）。A 组术后 24、48、72 h 及出院当天膝关节活动度均显著优于 B 组（ P<0.05），患者首次屈膝达 90° 时间较 B 组明显缩短（ t=–2.951， P=0.016）。术后 24 h 内使用盐酸哌替啶（50 mg/次）者，A 组 4 例、B 组 7 例；术后 24～48 h 使用，A 组 3 例、B 组 7 例；术后 48～72 h 使用，A 组 1 例、B 组 3 例。A 组 2 例发生置管处渗液，无 1 例发生置管脱落。.
置管持续 ACB 对 TKA 术后静息及活动状态下的镇痛效果均优于单次注射 ACB，能明显降低阿片类药物使用量，更有利于患者股四头肌肌力恢复，促进早期功能康复。.