We explored the efficacy of an interspace between the popliteal artery and capsule of the posterior knee (IPACK) block when added to an established enhanced recovery after surgery (ERAS) pathway to assist with posterior knee analgesia and functional mobility after total knee arthroplasty (TKA). We recruited participants undergoing TKA in our prospective, randomized, triple-blinded controlled trial. All study patients participated in our ERAS pathway consisting of a primary spinal anesthetic, adductor canal nerve catheter, and periarticular joint infiltration. Patients were randomized to receive an IPACK block or no block. The primary outcome was total postoperative opioid consumption. Secondary outcomes included pain scores, recovery unit length of stay, time to first opioid use, the incidence of posterior knee pain, ambulation distance and activities of daily living on postoperative day 1, and hospital length of stay. A total of 96 patients were randomized to the control and IPACK groups. There were no statistical differences in primary or majority of secondary outcomes. There was a lower incidence of posterior knee pain (39%) in the IPACK group when compared with controls (8.7%), p < 0.01. In terms of opioid consumption and a majority of functional outcomes, our study demonstrates no overall benefits of adding an IPACK block in this ERAS pathway in TKA. Nevertheless, IPACK may have the potential of mitigating posterior knee pain after TKA. Level of evidence: level 1.

Clinical trial number and registry URL: NCT03653416. www.clinicaltrials.gov.

我们探讨了将腘动脉和后膝关节囊 (IPACK) 阻滞剂之间的间隙添加到已建立的加速康复外科 (ERAS) 途径中以协助全膝关节置换术 (TKA) 后膝关节后部镇痛和功能活动的功效。我们在前瞻性、随机、三盲对照试验中招募了接受 TKA 的参与者。所有研究患者都参与了我们的 ERAS 途径，包括初级脊髓麻醉、内收肌管神经导管和关节周围关节浸润。患者被随机分配接受 IPACK 阻滞或不接受阻滞。主要结果是术后阿片类药物的总消耗量。次要结局包括疼痛评分、恢复单位住院时间、首次使用阿片类药物的时间、膝后疼痛的发生率、术后第 1 天的步行距离和日常生活活动以及住院时间。总共 96 名患者被随机分为对照组和 IPACK 组。主要或大多数次要结局没有统计学差异。与对照组 (8.7%) 相比，IPACK 组膝后疼痛的发生率 (39%) 较低，p  < 0.01。就阿片类药物的消耗和大多数功能结果而言，我们的研究表明在 TKA 的 ERAS 途径中添加 IPACK 块并没有总体益处。尽管如此，IPACK 可能具有减轻全膝关节置换术后膝后部疼痛的潜力。证据级别：1级。

临床试验编号和注册网址：NCT03653416。www.clinicaltrials.gov。