Background When combined with adductor canal block (ACB), local anesthetic infiltration between popliteal artery and capsule of knee (iPACK) is purported to improve pain following total knee arthroplasty (TKA). However, the analgesic benefits of adding iPACK to ACB in the setting of surgeon-administered periarticular local infiltration analgesia (LIA) are unclear.
Objectives To evaluate the analgesic benefits of adding iPACK to ACB, compared with ACB alone, in the setting of LIA following TKA.
Evidence review We conducted a meta-analysis of randomized trials comparing the effects of adding iPACK block to ACB versus ACB alone on pain severity at 6 hours postoperatively in adult patients undergoing TKA. We a priori planned to stratify analysis for use of LIA. Opioid consumption at 24 hours, functional recovery, and iPACK-related complications were secondary outcomes.
Findings Fourteen trials (1044 patients) were analyzed. For the primary outcome comparison in the presence of LIA (four trials, 273 patients), adding iPACK to ACB did not improve postoperative pain at 6 hours. However, in the absence of LIA (eight trials, 631 patients), adding iPACK to ACB reduced pain by a weighted mean difference (WMD) (95% CI) of −1.33 cm (−1.57 to –1.09) (p<0.00001). For the secondary outcome comparisons in the presence of LIA, adding iPACK to ACB did not improve postoperative pain at all other time points, opioid consumption or functional recovery. In contrast, in the absence of LIA, adding iPACK to ACB reduced pain at 12 hours, and 24 hours by a WMD (95% CI) of −0.98 (−1.79 to –0.17) (p=0.02) and −0.69 (−1.18 to –0.20) (p=0.006), respectively, when compared with ACB alone, but did not reduce opioid consumption. Functional recovery was also improved by a log(odds ratio) (95% CI) of 1.28 (0.45 to 2.11) (p=0.003). No iPACK-related complications were reported.
Conclusion Adding iPACK to ACB in the setting of periarticular LIA does not improve analgesic outcomes following TKA. In the absence of LIA, adding iPACK to ACB reduces pain up to 24 hours and enhances functional recovery. Our findings do not support the addition of iPACK to ACB when LIA is routinely administered.
- regional anesthesia
- nerve block
- lower extremity
Data availability statement
Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
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Contributors All authors provided equal contribution.
Funding Dr Brull receives research time support from the Evelyn Bateman Cara Operations Endowed Chair in Ambulatory Anesthesia and Women’s Health, Women’s College Hospital, and Merit Award Program, Department of Anesthesia and Pain Medicine, Toronto, Ontario, Canada.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.