加入局部浸润镇痛的多模式镇痛在全膝关节置换中的应用

 目的 探讨局部浸润镇痛在初次单侧全膝关节置换(total knee arthroplasty,TKA)术后多模式镇痛中的作用及安全性。方法 将60例拟行初次单侧TKA手术的患者随机分为局部浸润镇痛组与无局部浸润镇痛组,每组30例。两组均于术前3天给予塞来昔布口服(200 mg,2次/d),于手术室进行术侧股神经阻滞(3.3 g/L罗哌卡因30 ml)。采用静脉吸入复合麻醉。局部浸润镇痛组于术中假体安放完毕后行切口局部浸润镇痛(2.5 g/L罗哌卡因60 ml+0.1 mg肾上腺素);无局部浸润镇痛组不做切口局部浸润镇痛。术后均不使用静脉患者自控式镇痛泵。观察两组患者麻醉清醒后2、6、12、24、48、72 h及出院时的静息与活动疼痛视觉模拟评分(visual analogue scale,VAS);术后24、48、72 h关节活动度、股四头肌肌力及镇痛相关不良反应发生率。结果 局部浸润镇痛组术后各时点的静息及运动VAS评分均低于无局部浸润镇痛组,术后2 h至48 h静息VAS及24 h以后运动VAS的差异有统计学意义。局部浸润镇痛组术后24、48、72 h及出院时膝关节活动度、股四头肌肌力优于无局部浸润镇痛组,首次直腿抬高时间早于无局部浸润镇痛组,对阿片类药物的需求(哌替啶35.0 mg/例)少于无局部浸润镇痛组(哌替啶66.7 mg/例),镇痛相关不良反应发生率(2/30,6.7%)低于无局部浸润镇痛组(7/30,23.3%),术后平均住院时间(5.4 d)少于无局部浸润镇痛组(6.8 d),差异均有统计学意义。结论 以股神经阻滞联合局部浸润镇痛为主的多模式镇痛在初次单侧TKA术后有较好的镇痛效果。     

Pain control after total knee arthroplasty: a randomized trial comparing local infiltration anesthesia and continuous femoral block

Background and purpose Pain after total knee arthroplasty (TKA) is usually severe, and epidural analgesia or femoral nerve block has been considered to be an effective pain treatment. Recently, local infiltration analgesia (LIA) has become increasingly popular but the outcome of this method regarding the analgesic effect has not been fully evaluated. We compared local infiltration analgesia and femoral block with regard to analgesia and morphine demand during the first 24 h after TKA.

Methods 40 patients undergoing TKA under spinal anesthesia were randomized to receive femoral nerve block (group F) or peri- and intraarticular infiltration analgesia (group LIA) with a mixture containing ropivacaine, ketorolac, and epinephrine. All patients had access to intravenous patient-controlled analgesia (PCA) with morphine postoperatively. Pain intensity at rest and upon movement was assessed on a numeric rating scale (0–10) on an hourly basis over 24 h if the patients were awake.

Results The average pain at rest was marginally lower with LIA (1.6) than with femoral block (2.2). Total morphine consumption per kg was similar between the 2 groups. Ancillary analysis revealed that 1 of 20 patients in the LIA group reported a pain intensity of > 7 upon movement, as compared to 7 out of 19 in the femoral block group (p = 0.04).

Interpretation Both LIA and femoral block provide good analgesia after TKA. LIA may be considered to be superior to femoral block since it is cheaper and easier to perform.     

The adductor canal catheter and interspace between the popliteal artery and the posterior capsule of the knee for total knee arthroplasty

Analgesia for total knee arthroplasty (TKA) is not a new topic; however, some newer approaches to peripheral nerve blocks for control of postoperative pain have been developed. The femoral nerve block plus or minus a sciatic nerve block has been shown to provide effective analgesia, but not without some degree of motor block. The adductor canal block provides analgesia not inferior to a femoral with less motor weakness, and a continuous catheter technique can be used to prolong its effects. Blocking the sciatic nerve has been a subject of controversy, in part because of the motor weakness but also because of the inclusion of the common peroneal nerve, a nerve that can potentially be damaged by TKA. An infiltration of the interspace between the popliteal artery and the capsule of the posterior knee, provides analgesia for the posterior knee without motor effects or common peroneal block. The combination of an adductor canal catheter and an interspace between the popliteal artery and the capsule of the posterior knee provides a balance of effective postoperative analgesia and preservation of motor function, ultimately shortening length of stay following TKA.     

Improved pain control after cardiac surgery: results of a randomized, double-blind, clinical trial

OBJECTIVE: We sought to determine whether a continuous regional infusion of a local anesthetic delivered to the operative site would result in decreased levels of postoperative pain and narcotic requirements for patients who undergo a standard median sternotomy for cardiac surgery. METHODS: A double-blind, randomized, controlled trial was conducted at a single center. Patients who were undergoing elective coronary artery bypass graft surgery alone or combined with laser transmyocardial revascularization received bilateral intercostal nerve blocks with either ropivacaine or saline. At wound closure, 2 catheters with multiple side openings were inserted percutaneously and placed directly over the sternum. The same agent (ropivacaine vs saline) was then administered as a continuous regional infusion for 48 hours through an elastomeric pump. Requirements for postoperative systemic narcotic analgesics and pain assessment scores were recorded for 72 hours after the operation. Secondary outcome measures were hospital length of stay and pulmonary function test results. Pain scores and narcotic use on the second postoperative day were also compared to avoid the confounding influence of anesthesia administered at the time of the operation. RESULTS: The total amount of narcotic analgesia required by the ropivacaine group was significantly less than that of the control group (47.3 vs 78.7 mg, respectively; P =.038). The ropivacaine group required less narcotics on postoperative day 2 as well (15.5 vs 29.4 mg, P =.025). The mean overall pain scores for the ropivacaine group were significantly less than the mean overall scores for the normal saline group (1.6 vs 2.6, respectively; P =.005). Patients receiving ropivacaine had a mean length of stay of 5.2 days compared with 8.2 days for patients in the normal saline group (P =.001). Excluding the data from outliers (length of stay = 39 days), the normal saline group mean length of stay was 6.3 days (P <.01). There was no difference in assessment of pulmonary function. CONCLUSION: Continuous delivery of local anesthetics significantly improved postoperative pain control while decreasing the amount of narcotic analgesia required in patients who underwent standard median sternotomy. There was also a significant decrease in hospital length of stay, which is likely to result in significant cost reductions.     

Effects of local infiltration analgesia for posterior knee pain after total knee arthroplasty: comparison with sciatic nerve block

Background

Although femoral nerve block provides good analgesia after total knee arthroplasty (TKA), residual posterior knee pain may decrease patient satisfaction. We compared the efficacy of periarticular infiltration analgesia (PIA) and sciatic nerve block (SNB) for posterior knee pain.

Methods

Forty-nine patients scheduled for TKA were prospectively randomized into the PIA group (n = 25) or SNB group (n = 24) and received general anesthesia with ultrasound-guided femoral nerve block (FNB). In the PIA group, 60 ml 0.5 % ropivacaine and 0.3 mg epinephrine were injected intraoperatively into the periarticular soft tissue before inserting the components. In the SNB group, patients received ultrasound-guided SNB with 20 ml 0.375 % ropivacaine and periarticular infiltration with 20 ml normal saline and 0.3 mg epinephrine. We evaluated postoperative pain scores, posterior knee pain, frequency of rescue analgesics for 36 h, and performance time of PIA and SNB.

Results

Visual analogue pain scores at 12–24 h were significantly lower in the PIA group than in the SNB group (p < 0.05). The majority of patients had no posterior knee pain. There were no significant differences between the groups in frequency and time of first administration of rescue analgesics and in side effects. Time for performance of periarticular infiltration was significantly shorter than that for SNB (p < 0.05). The dose of intraoperative remifentanil was significantly lower in the SNB group than in the PIA group (p < 0.001).

Conclusions

The combination of FNB and PIA provides sufficient analgesia after TKA. The rapid and convenient periarticular infiltration technique could be a good alternative to SNB.     

Doubtful effect of continuous intraarticular analgesia after total knee arthroplasty

Background and purpose — Local infiltration analgesia (LIA) is well established for effective postoperative pain relief in total knee arthroplasty (TKA). To prolong the effect of LIA, infusion pumps with local intraarticular analgesia can be used. We evaluated the effect of such an infusion pump for the first 48 h postoperatively regarding pain, knee function, length of stay (LOS) in hospital, and complications.

Patients and methods — 200 patients received peroperative LIA and a continuous intraarticular elastomeric infusion pump set at 2 mL/h. The patients were randomized either to ropivacaine (7.5 mg/mL) or to NaCl (9 mg/mL) in the pump. Visual analog scale (VAS) pain (0–100 mm), analgesic consumption, side effects of medicine, range of motion (ROM), leg-raising ability, LOS, and complications during the first 3 months were recorded.

Results — On the first postoperative day, the ropivacaine group had lower VAS pain (33 vs. 40 at 12 noon and 36 vs. 43 at 8 p.m.; p = 0.02 and 0.03, respectively), but after that all recorded variables were similar between the groups. During the first 3 months, the ropivacaine group had a greater number of superficial and deep surgical wound infections (11 patients vs. 2 patients, p = 0.02). There were no other statistically significant differences between the groups.

Interpretation — Continuous intraarticular analgesia (CIAA) with ropivacaine after TKA has no relevant clinical effect on VAS pain and does not affect LOS, analgesic consumption, ROM, or leg-raising ability. There may, however, be a higher risk of wound-healing complications including deep infections.     

Effects of a preoperative femoral nerve block on pain management and rehabilitation after total knee arthroplasty

The objective of this prospective, randomized, double-blind study was to determine if preoperative administration of a femoral nerve block reduces the amount of morphine needed for postoperative analgesia after total knee arthroplasty (TKA). Forty-two patients undergoing TKA were randomly assigned to receive either a femoral nerve block (0.50% bupivacaine hydrochloride with epinephrine 1:200,000) or matching placebo. Results showed postoperative morphine use was significantly lower in patients who received the nerve block (25.5 vs 37.5 mg, P = .016); however, the 2 groups had similar pain scores and rehabilitative outcomes. In general, a preoperative femoral nerve block is a safe and effective adjunct for decreasing morphine use for post-TKA analgesia.     

Effects of a preoperative femoral nerve block on pain management and rehabilitation after total knee arthroplasty.

The objective of this prospective, randomized, double-blind study was to determine if preoperative administration of a femoral nerve block reduces the amount of morphine needed for postoperative analgesia after total knee arthroplasty (TKA). Forty-two patients undergoing TKA were randomly assigned to receive either a femoral nerve block (0.50% bupivacaine hydrochloride with epinephrine 1:200,000) or matching placebo. Results showed postoperative morphine use was significantly lower in patients who received the nerve block (25.5 vs 37.5 mg, P = .016); however, the 2 groups had similar pain scores and rehabilitative outcomes. In general, a preoperative femoral nerve block is a safe and effective adjunct for decreasing morphine use for post-TKA analgesia.     

Effectiveness of 3-in-1 continuous femoral block of differing concentrations compared to patient controlled intravenous morphine for post total knee arthroplasty analgesia and knee rehabilitation

We assessed the effectiveness of the 3-in-1 continuous femoral block as a form of postoperative pain relief for unilateral total knee arthroplasty (TKA). Sixty patients undergoing elective unilateral TKA under subarachnoid block were randomized into three groups. Postoperative analgesia was provided with a continuous 3-in-1 femoral nerve catheter with 0.15% ropivacaine in group A, a continuous 3-in-1 femoral nerve catheter with 0.2% ropivacaine in group B, or patient controlled intravenous morphine in group C (control group). Groups A and B received patient controlled intravenous morphine pumps for rescue analgesia. Patients in each group were followed for 72 hours postoperatively. Five patients were excluded after randomization. In the remaining 55 patients there was no statistical difference in pain score between the groups. Total morphine use was highest in group C (P < 0.05). No appreciable difference could be found with sensorimotor blockade, morphine usage and satisfaction scores when comparing groups A and B. Femoral catheter dislodgement rate was 7.9%. There was no statistical difference between the groups when comparing the day of first ambulation and the time to discharge from the hospital. Satisfaction scores were higher in group A (P = 0.028) and group B (P = 0.002) compared to group C. We conclude that a continuous 3-in-1 femoral nerve block with ropivacaine 0.15% or 0.2% for elective unilateral TKA has an opioid-sparing effect.     

Comparison of Local Infiltration of Analgesia and Sciatic Nerve Block in Addition to Femoral Nerve Block for Total Knee Arthroplasty

We conducted a prospective randomized controlled trial to test the null hypothesis that there is no difference between sciatic nerve block (SNB) and local infiltration of analgesia (LIA) regarding postoperative analgesia after total knee arthroplasty (TKA), when administrated in addition to femoral nerve block (FNB). Forty-six patients scheduled for TKA were randomized into two groups: concomitant administration of FNB and SNB or FNB and LIA. Average pain scores during the first 21 days after surgery were similar in the two groups and remained at low level. There was no significant difference in the need for adjuvant analgesics, patient satisfaction level, the time to achieve rehabilitation goals, and length of hospital stay. The LIA offers a potentially safer alternative to SNB as an adjunct to FNB.     

收肌管阻滞联合腘动脉-膝关节囊后间隙阻滞或胫神经阻滞在全膝关节置换术中的应用

目的 比较收肌管阻滞(ACB)联合腘动脉-膝关节囊后间隙阻滞(IPACK)或选择性胫神经阻滞(TNB)用于全膝关节置换术的镇痛效果及对运动功能的影响.方法 选择2020年4—6月行全膝关节置换术老年患者60例,男28例,女32例,年龄65～84岁,ASAⅡ或Ⅲ级.采用随机数字表法分为两组:IPACK组(I组)和TNB组...     

A randomized, controlled trial comparing local infiltration analgesia with epidural infusion for total knee arthroplasty

Background

There have been few studies describing wound infiltration with additional intraarticular administration of multimodal analgesia for total knee arthroplasty (TKA). In this study, we assessed the efficacy of wound infiltration combined with intraarticular regional analgesia with epidural infusion on analgesic requirements and postoperative pain after TKA.

Methods

40 consecutive patients undergoing elective, primary TKA were randomized into 2 groups to receive either (1) intraoperative wound infiltration with 150 mL ropivacaine (2 mg/mL), 1 mL ketorolac (30 mg/mL), and 0.5 mL epinephrine (1 mg/mL) (total volume 152 mL) combined with intraarticular infusion (4 mL/h) of 190 mL ropivacaine (2 mg/mL) plus 2 mL ketorolac (30 mg/mL) (group A), or (2) epidural infusion (4 mL/h) of 192 mL ropivacaine (2 mg/mL) combined with 6 intravenous administrations of 0.5 mL ketorolac (30 mg/mL) for 48 h postoperatively (group E). For rescue analgesia, intravenous patient-controlled-analgesia (PCA) morphine was used.Morphine consumption, intensity of knee pain (0–100 mm visual analog scale), and side effects were recorded. Length of stay and corrected length of stay were also recorded (the day-patients fulfilled discharge criteria).

Results

The median cumulated morphine consumption, pain scores at rest, and pain scores during mobilization were reduced in group A compared to group E. Corrected length of stay was reduced by 25% in group A compared to group E.

Interpretation

Peri- and intraarticular analgesia with multimodal drugs provided superior pain relief and reduced morphine consumption compared with continuous epidural infusion with ropivacaine combined with intravenous ketorolac after TKA.Total knee arthroplasty (TKA) usually results in severe postoperative pain. Continuous epidural infusion with a local anesthetic is a standard regime for postoperative analgesia after TKA. Epidural analgesia and also peripheral nerve block analgesia have been shown to reduce opioid consumption compared with intravenous patient-controlled analgesia (PCA). Even though both modalities reduce the occurrence of the well-known side effects of opioid drugs, they involve extra equipment and are associated with substantial side effects (Choi et al. 2003, Davies et al. 2004, Boezaart 2006). Wound infiltration with multimodal analgesia has been a controversial issue for many years (Dahl et al. 1994). Different modes of perioperative analgesia either without or combined with intraarticular infusion or bolus injection(s) for both TKA and total hip arthroplasty have been described (Bianconi et al. 2003, Rasmussen et al. 2004, Reilly et al. 2005, Andersen et al. 2007a, b). Only a few studies have described high-volume peri- and intraarticular analgesia for TKA (Busch et al. 2006, Vendittoli et al. 2006, Toftdahl et al. 2007). The hypothesis in our trial was that wound infiltration and intraarticular infusion of ropivacaine and ketorolac would reduce opioid consumption during the active treatment period (0–48 h postoperatively) after TKA compared to epidural infusion of ropivacaine and intravenous ketorolac. Primary outcome was 48-h opioid use. Secondary outcomes included pain at rest and during mobilization, side effects, length of hospital stay (LOS), and corrected length of stay (the day-patients fulfilled discharge criteria).     

局部浸润罗哌卡因联合静脉镇痛对全膝关节置换术后镇痛及早期康复的影响

目的评估伤口单次局部浸润罗哌卡因联合静脉自控镇痛对全膝关节置换(TKA)术后镇痛的效果及术后早期膝关节康复训练的影响。方法选择腰麻下行膝关节置换手术的患者50例,根据镇痛方式分为两组,罗哌卡因组(25例):术毕切口浸润0.25%罗哌卡因20 ml,术后行静脉自控镇痛(PCIA);对照组(25例):术毕切口浸润生理盐水20 ml,术后行PCIA。采用视觉模拟评分法(VAS)评估不同时间点的镇痛效果,不同时间评定术后康复训练依从性、膝关节主动活动度(ROM)、膝关节功能。结果术后4、6、8、12 h VAS评分:罗哌卡因组分别为1.28分±1.03分、2.17分±1.67分、2.13分±1.76分、2.38分±0.34分,对照组分别为2.75分±1.09分、3.25分±1.29分、4.50分±1.51分、4.62分±1.60分,两组比较差异有统计学意义(P0.01)。术后24、48 h VAS评分:罗哌卡因组分别为3.20分±1.21分、3.17分±0.84分,对照组分别为3.28分±1.21分、3.56分±1.19分,两组比较差异无统计学意义(P0.05)。罗哌卡因组与对照组术后康复训练依从性、膝关节ROM及HSS评分比较差异均有统计学意义(P0.01)。结论应用罗哌卡因局部浸润联合PCIA用于TKA术后镇痛是一种安全有效的镇痛方法,有利于膝关节术后功能的恢复,具有较好的临床应用价值。     

A single injection ultrasound-assisted femoral nerve block provides side effect-sparing analgesia when compared with intrathecal morphine in patients undergoing total knee arthroplasty

Postoperative pain after total knee arthroplasty (TKA) is severe, and achieving adequate analgesia remains a clinical challenge. We tested the hypothesis that, in patients having unilateral TKA under intrathecal (IT) anesthesia, the addition of a femoral nerve block would provide superior analgesia when compared with IT morphine and demonstrate fewer adverse side effects. In a single-blinded and controlled trial, 41 ASA I-III patients undergoing unilateral TKA were randomized into 2 groups. Both groups received 15 mg of IT hyperbaric bupivacaine for the surgical anesthetic. Group ITM received 250 microg of IT morphine and group FNB received an ultrasound-assisted femoral nerve block with 40 mL of 0.5% ropivacaine, 5 microg/mL of epinephrine, and 75 microg of clonidine. At 1, 2, 4, 6, 12, and 24 h postoperatively, we measured visual analog scales for pain, cumulative IV morphine consumption, hemodynamics, and side effects. There were no statistically significant differences in morphine consumption, pain at rest, or pain with movement. However, group FNB had fewer perioperative side effects including nausea, vomiting, and pruritus (P < 0.05 for each event). This corresponded to a decrease in patient satisfaction in group ITM, in which 20% of the patients rated their experience as "unsatisfactory" (P < 0.05). We conclude that, in comparison with IT morphine, a single injection femoral nerve block provides equivalent analgesia but with a significant reduction in side effects for patients having TKA under bupivacaine intrathecal anesthesia.     

A comparison of epidural analgesia with combined continuous femoral-sciatic nerve blocks after total knee replacement

Epidural analgesia remains the "gold standard" of pain relief after total knee replacement. However, peripheral nerve block is gaining popularity because the incidence of side effects may be reduced. Our study tests this postulate. Sixty patients were prospectively randomized to receive either epidural infusion or combined continuous femoral and sciatic nerve blocks. Ropivacaine 2 mg/mL plus sufentanil 1 mug/mL was given either epidurally or through the femoral nerve catheter, and ropivacaine 0.5 mg/mL was given through the sciatic nerve catheter using elastomeric infusers (delivering 5 mL/h for 55 h). The primary outcome measure was the total incidence of side effects (urinary retention and moderate to severe degrees of dizziness, pruritus, sedation, and nausea/vomiting on the first postoperative day). Intensity of motor blockade, pain at rest and on mobilization, and rehabilitation indices were also registered for 72 h. One or more side effects were present in 87% of patients in the epidural group whereas only 35% of patients in the femoral and sciatic block groups were affected on the first postoperative day (P = 0.0002). Motor blockade was more intense in the operated limb on the day of surgery and the first postoperative day in the peripheral nerve block group (P = 0.001), whereas the non-operated limb was more blocked in the epidural group on the day of surgery (P = 0.0003). Pain on mobilization was well controlled in both groups and there were no differences in the length of hospital stay. Rehabilitation indices were similar. The results demonstrate a reduced incidence of side effects in the femoral/sciatic nerve block group than in the epidural group on the first postoperative day.     

The Efficacy and Safety of Regional Nerve Blocks in Total Knee Arthroplasty: Systematic Review and Direct Meta-Analysis

BackgroundRegional nerve blocks are widely used in primary total knee arthroplasty (TKA) to reduce postoperative pain and opioid consumption. The purpose of our study was to evaluate the efficacy and safety of regional nerve blocks after TKA in support of the combined clinical practice guidelines of the American Association of Hip and Knee Surgeons, American Academy of Orthopaedic Surgeons, Hip Society, Knee Society, and American Society of Regional Anesthesia and Pain Management.MethodsWe searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials for studies published before March 24, 2020 on femoral nerve block, adductor canal block, and infiltration between Popliteal Artery and Capsule of Knee in primary TKA. All included studies underwent qualitative and quantitative homogeneity testing followed by a systematic review and direct comparison meta-analysis to assess the efficacy and safety of the regional nerve blocks compared to a control, local peri-articular anesthetic infiltration (PAI), or between regional nerve blocks.ResultsCritical appraisal of 1,673 publications yielded 56 publications representing the best available evidence for analysis. Femoral nerve and adductor canal blocks are effective at reducing postoperative pain and opioid consumption, but femoral nerve blocks are associated with quadriceps weakness. Use of a continuous compared to single shot adductor canal block can improve postoperative analgesia. No difference was noted between an adductor canal block or PAI regarding postoperative pain and opioid consumption, but the combination of both may be more effective.ConclusionSingle shot adductor canal block or PAI should be used to reduce postoperative pain and opioid consumption following TKA. Use of a continuous adductor canal block or a combination of single shot adductor canal block and PAI may improve postoperative analgesia in patients with concern of poor postoperative pain control.     

Reconstruction of the medial patellofemoral ligament for treatment of patellar instability

Background and purpose Postoperative pain is often severe after total knee arthroplasty (TKA). We investigated the efficacy of the local infiltration analgesia (LIA) technique, both intraoperatively and postoperatively.

Methods 48 patients undergoing TKA were randomized into 2 groups in a double-blind study. In group A, 400 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine were infiltrated periarticularly during operation. In group P, no injections were given. 21 h postoperatively, 200 mg ropivacaine, 30 mg ketorolac, and 0.1 mg epinephrine were injected intraarticularly in group A, and the same volume of saline was injected in group P. All patients were followed up for 3 months.

Results Median morphine consumption was lower in group A during the first 48 h: 18 (1–74) mg vs. 87 (36–160) mg in group P. Postoperative pain was lower at rest in group A during the first 27 h, and on movement during the first 48 h, except at 21 h. Time to fulfillment of discharge criteria was shorter in group A than in group P: 3 (1–7) vs. 5 (2–8) days. Patient satisfaction was higher in group A than in group P on days 1 and 7. The unbound venous blood concentration of ropivacaine was below systemic toxic blood concentrations.

Interpretation The local infiltration analgesia (LIA) technique provides excellent pain relief and lower morphine consumption following TKA, resulting in shorter time to home readiness and higher patient satisfaction. There were few side effects and systemic LA concentrations were low.     

Dexmedetomidine Prolongs the Analgesic Effects of Periarticular Infiltration Analgesia following Total Knee Arthroplasty: A Prospective,Double-Blind,Randomized Controlled Trial

BackgroundPeriarticular infiltration analgesia (PIA) is widely administered to relieve postoperative pain following total knee arthroplasty (TKA). The present study aimed to evaluate the effect of prolonging the analgesic duration by adding dexmedetomidine to PIA for pain management after TKA.MethodsOne hundred and sixteen patients were randomly allocated into 3 groups based on PIA regimens including group R (ropivacaine), group E (ropivacaine plus epinephrine), and group D (ropivacaine plus dexmedetomidine). The primary outcomes were postoperative visual analog scale scores, time until the administration of first rescue analgesia, and opioid consumption. The secondary outcomes included postoperative inflammatory biomarkers and functional recovery. The tertiary outcomes were postoperative complications and adverse events.ResultsThe patients in group D had significantly lower resting visual analog scale scores than those in groups R and E at 6 hours after surgery. Group R showed the higher pain scores at rest and motion than groups D and E 12 hours postoperatively. The use of dexmedetomidine or epinephrine postponed the time until the administration of first rescue analgesia and led to lower opioid consumption in the first 24 hours after TKA. The levels of interleukin-8 and tumor necrosis factor-α in groups D and E were significantly lower than those in group R on postoperative day 3. Furthermore, no significant differences were observed in functional recovery, postoperative complications, or adverse events among the three groups.ConclusionsAdding dexmedetomidine as an adjuvant to PIA could potentiate and prolong the analgesic effect in the early stage following TKA without increasing the risk of adverse events.