Researchers determined the meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy and safety of local infiltration anesthesia (LIA) versus epidural analgesia (EPA) for postoperative pain control in total knee arthroplasty (TKA).

Appropriate pain control is a prerequisite to promoting early mobilization and functional recovery after TKA. Several options are available for postoperative pain management following TKA, but all of them have shortcomings. Epidural analgesia consisting of a local anesthetic agent and an opioid has been a regular regimen used for postoperative analgesia after TKA.

However, some studies have indicated that the benefit of epidural analgesia must be weighed against the frequency of its adverse effects such as urinary retention, hypotension, pruritus, and motor block that delays mobilization. The advantage of LIA is the ability to provide pain control without interfering with lower extremity motor strength, thereby allowing early mobilization of patients.

Studies have shown that LIA is consistently more effective in the treatment of postoperative pain after TKA when compared with placebo. There was still controversy about which protocol is more suitable for pain control after TKA. Therefore, we searched for relevant studies and performed a meta-analysis comparing LIA versus epidural anesthesia for reducing pain intensity in TKA patients.

Current meta-analysis indicated that LIA has an equivalent efficacy for pain-relieving with rest of mobilization at an early period and late period than EPA after TKA. LIA was associated with an increase of the range of motion than EPA at an early period after TKA. And LIA was associated with a reduction of the occurrence of nausea and the length of hospital stay than EPA. There was no significant difference between the occurrence of infection.

They conducted a recent meta-analysis of RCTs showing that LIA achieves better analgesic effects comparing with EPA. Our meta-analysis also has several potential limitations that should be taken into account when considering the benefits. First, our analysis comprised only seven RCTs, but one of them had a modest sample size (n < 100). Compared to large sample size studies, small sample size studies are inclined to overestimate the intervention effect, which limits the power of inference.

Second, although the effect size in the funnel plot was symmetrical, they could not exclude the publication bias due to the small number of the included studies. Meanwhile, the relatively short follow-up duration will underestimate the complications.

Although the overall quality of the evidence can be considered “middle,” they objectively assessed the benefits and risk of LIA and EPA. Based on this meta-analysis of all currently published RCTs, the findings have important implications for the medical community, namely, that LIA is an effective alternative to provide less length of hospital stay and nausea but provides a comparable level of pain relief in comparison with the EPA.