Local infiltration of anesthesia (LIA) was shown to provide improved post-operative analgesia at rest when compared to regional nerve block (RB) and epidural analgesia (EA), according to findings from a meta-analysis published in Pain Physician. Additional benefits to utilizing LIA include preservation of quadriceps function in the early post-operative period, which may have implications for improved functional recovery and early mobilization post-operatively.
Total knee arthroplasty (TKA) is an increasingly common operative procedure, especially for indication such as osteoarthritis, and is associated with a need for good post-operative pain control since early mobilization is important for optimal functional outcomes.
Neuraxial analgesia methods, including insertion of epidural catheters for post-operative pain relief are increasingly used in conjunction with TKA procedures. The use of neuraxial blockade, while effective, can also be associated with potentially unwanted side effects including hypotension, urinary retention, pruritis, and the risk of spinal infection.
As a result, the use of peripheral nerve blocks (PNBs) including femoral nerve block, sciatic nerve block, obturator nerve block, and adductor canal block, have been increasingly used to augment pain control in patients undergoing TKA. These nerve blocks are associated with their own downsides, including unwanted prolonged effects of motor nerves that may prevent the orthopedic surgery teams from conducting a thorough neurological post-operative examination following TKA.
The use of intra-operative LIA has advanced the utilization of multimodal pain control, and has contributed to the progression of pain control in TKA procedures. To examine the clinical utility of LIA as compared to RB and neuraxial analgesia, Bin Hu, MD, of the Department of Orthopaedic Surgery, Wenzhou Medical University, Ningbo, People’s Republic of China, and colleagues collated studies for meta-analysis, including randomized controlled trials (RCTs) that compared LIA to RB with the primary outcome studied being efficacy of post-operative pain control, amount of morphine consumption, time to functional recovery, complication profile, and length of hospitalization.
Researchers searched Embase, Medline, Cochrane Library, CINAHL, Web of Science, and Scopus for RCTs evaluating the efficacy and safety of LIA compared to RB for postoperative pain control following TKA. Nonrandomized trials, case reports, editorials, letters, commentaries, and comparative studies that did not state inclusion criteria were excluded for data analysis.
The meta-analysis found that when LIA was used for post-operative pain control post-TKA, a significantly lower numeric rating scale (NRS) score was obtained at rest, when compared to those patients who received RB (Weighted mean difference [WMD]: -0.40 [-0.72, -0.07]; P = .02). Morphine consumption did not differ between groups (WMD: -1.39 [-7.21, 4.44]; P = .64).
Patients who received LIA had increased ability to perform the straight leg test on post-operative day 1 as compared to those receiving TB (RR: 2.90 [2.15, 3.93]; P < .00001). These patients also demonstrated improved range of motion within 1 week of surgery as compared to those receiving RB (WMD: 4.33 [2.61, 6.05]; P < .00001). There were minor differences in inpatient hospitalization between patients receiving LIA and RB (WMD: -0.25 [-0.49, -0.01]; P = .05).
Summary and Clinical Applicablity
In this pooled meta-analysis, LIA provided better analgesia at rest in the immediate post-operative period when compared to RB, in addition to preserving quadriceps function.
Limitations and Disclosures
A randomized clinical trial, adequately powered, would need to be performed to validate the results in this study.
Conflict-of-interest issues regarding the authorship or article: None declared
Hu B, Lin T, Yan SG, et al. Local Infiltration Analgesia Versus Regional Blockade for Postoperative Analgesia in Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Trials. Pain Physician. 2016;19(4):205-14.