This work is licensed under a Abstract
Purpose
The objective of this study was to assess the benefits of the PENG block on pain control and functional recovery.
Methods
Randomized controlled trials in PubMed, Web of Science, Embase, and the Cochrane Library were selected, and data were meta-analyzed using a random-effects model to estimate mean difference (MD) or standardized mean differences (SMD).
Results
Eleven trials involving 1,135 patients were included. The PENG block was associated with significantly lower total opioid consumption than sham/no block (MD: −25.23, 95% CI: −27.01 to −23.45, I2 = 0%), as well as better functional recovery. The PENG block was noninferior to the suprainguinal fascia iliaca block regarding postoperative pain scores and functional recovery and had a significant reduction in total opioid consumption (MD: −8.25, 95% CI: −16.48 to −0.02, I2 = 68%). The PENG block was associated with similar total opioid consumption and functional recovery as the periarticular anesthetic infiltration (PAI), but worse static pain scores at 12 h (SMD: 0.41, 95% CI: 0.08–0.75, I2 = 51%) and dynamic pain scores at 48 h after surgery (SMD: 0.36, 95% CI: 0.08–0.64, I2 = 0%).
Conclusions
While current evidence supports the PENG block as a viable alternative to other types of peripheral analgesia in THA, existing data remain insufficient to conclude that the PENG block outperforms other peripheral analgesia when it comes to pain control or functional recovery. More well-designed randomized controlled trials are needed in the future to thoroughly explore whether the PENG block has superiority over other analgesic techniques.
Keywords: pericapsular nerve group, total hip arthroplasty, pain, opioid consumption, functional recovery
Introduction
Total hip arthroplasty (THA) is one of the most effective treatments for painful, deformed, or damaged hip joints. In the United States alone, more than 262,369 such procedures were performed in 2019, and it is expected to reach 710,000 by 2040 (1). To control the moderate to severe pain that can occur after the procedure (2), peripheral analgesia is usually applied as part of a multimodal analgesic strategy (3). This strategy can include the suprainguinal fascia iliaca block (SFIB), which is a fascial plane block (4), or the periarticular anesthetic infiltration (PAI), in which analgesics are injected around the joints to control pain without weakening muscles (5). While these various approaches are known to control pain well and promote functional recovery after total knee arthroplasty, the efficacy of PAI in THA is controversial (6, 7, 8). In addition, SFIB may weaken the quadriceps muscle after hip surgery, delaying functional recovery (9).
The pericapsular nerve group (PENG) block is a novel peripheral nerve block in which the articular branches of the femoral, obturator, and accessory obturator nerves are targeted under ultrasound guidance to control pain while sparing motor function (10). Recently, increasing studies have reported the efficacy of the PENG block in pain control and functional recovery following THA, but have come to conflicting conclusions. Some studies reported that PENG blocks have lower postoperative pain, lower opioid consumption, and better postoperative hip function (9, 11), while others show that PENG blocks have similar pain control or functional recovery as other types of analgesia (5, 12, 13). To make matters worse, the conclusion is also inconsistent across studies that compared the PENG block with sham/no block (14, 15).
The quality of evidence in several recent meta-analyses is also of concern. These include pooled data from different anesthetic types (16), as well as subject populations (17), even including the combination of PENG block and PAI (16, 17). In addition, those studies did not evaluate functional recovery, which is an important determinant of prognosis. Given the limitations of existing studies and the availability of high-quality randomized controlled trials, the present study—divided into three subgroups based on the type of anesthesia in the control group, i.e. sham/no block, SFIB, and PAI—was conducted to perform a comprehensive and up-to-date systematic review and meta-analysis to assess the efficacy of the PENG block after THA.
Methods
This study has been reported in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) (18) and AMSTAR (Assessing the Methodological Quality of Systematic Reviews) (19) guidelines. Ethical approval was considered unnecessary because only anonymized data already published in peer-reviewed journals were used. The present study was registered on PROSPERO (Registration number: CRD42023470161).
Search strategy
Two independent researchers systematically searched the electronic databases of PubMed, Web of Science, Embase, and the Cochrane Library for relevant studies using combinations of MESH terms and keywords related to the pericapsular nerve group and THA, as well as the term ‘randomized controlled trial’. The search was conducted up to April 30, 2024. Search strategies applied to each database can be found in Appendix 1 (see section on Supplementary materials given at the end of the article). No date or language restrictions were applied. Reference lists in relevant articles were also manually searched for additional eligible trials.
Study selection
Studies had to satisfy the following inclusion criteria based on the PICOS principle: the participants were adults who underwent THA; the intervention was the PENG block; the comparator was sham/no block or SFIB, or PAI; outcomes were pain control, functional recovery, and complications after surgery; and study design was randomized controlled trial. Studies were excluded if they combined the PENG block with another type of peripheral anesthesia.
Data extraction
Two researchers independently extracted the base and block information from the included literature using a pre-established form. Data on pain control were collected in the form of total opioid consumption (in terms of oral morphine equivalents (20)) and/or static or dynamic pain scores at 3, 6, 12, 24, and 48 h after surgery. Data on functional recovery were collected in terms of muscle strength, motor block, and functional performance. Data were collected on the following complications: postoperative nausea and vomiting (PONV), urinary retention, respiratory depression, pruritus, and puncture complications. If data for the same outcome could not be pooled across studies, they were converted to a single form suitable for pooling using formulas in the Cochrane Handbook (Version 6.5, 2024) (21).
Evaluation of study bias
Two researchers independently evaluated the risk of bias in the included literature according to the Cochrane Collaboration’s tool for assessing bias risk in randomized trials (21).
Statistical analysis
Statistical analysis was performed using R 4.3.1. Data were pooled using the ‘metacont’ and ‘metabin’ functions. All meta-analyses were performed using a random-effects model because we anticipated substantial differences across studies in the approach during THA, composition of analgesic cocktails, and basic analgesic protocols. Heterogeneity across studies was assessed using the I2 test, with I2 > 50% defined as substantial heterogeneity (22). When I2 > 50%, sensitivity analyses were conducted to identify potential sources of heterogeneity and evaluate the robustness of the results. The quality of evidence for the meta-analysis results was assessed using the ‘Grading of Recommendations Assessment, Development and Evaluation’ (GRADE) system (23).
Results
We retrieved 152 potentially relevant publications from four electronic databases and other resources, which fell to 88 after removing duplicates, then to 29 after screening based on titles and abstracts, leaving 14 that were read in full. After excluding three studies that evaluated the combination of PENG block and PAI (24, 25, 26), we were left with 11 studies involving 1,135 patients (5, 9, 11, 12, 13, 14, 15, 27, 28, 29, 30) (Fig. 1, Tables 1 and 2).
Figure 1.
Flowchart of study selection.
Table 1.
Characteristics of the randomized controlled trials in this review.
| Study | Country | THA approach | Sample size (n(M)) | Age (mean ± SD) | ||
|---|---|---|---|---|---|---|
| T | C | T | C | |||
| Aliste et al. (9) | Chile | PA | 20 (7) | 20 (7) | 56.8 ± 13.0 | 59.6 ± 9.2 |
| Bravo et al. (27) | Chile | PLA | 30 (8) | 30 (13) | 60.6 ± 11.1 | 59.5 ± 10.0 |
| Carella et al. (28) | Belgium | PLA | 51 (24) | 51 (21) | 68.2 ± 10.5 | 64.8 ± 12.7 |
| Choi et al. (29) | South Korea | PA | 27 (14) | 27 (16) | 60.5 ± 18.4 | 61.9 ± 14.9 |
| Domagalska et al. (14) | Poland | PA | 239 (140) | 237 (122) | 66.0 ± 5.8 | 66.0 ± 5.1 |
| Et et al. (12) | Turkey | PLA | 30 (13) | 29 (13) | 68.8 ± 11.1 | 68.5 ± 13.1 |
| Iglesias et al. (30) | Argentina | PLA | 20 (9) | 20 (12) | 60.6 ± 10.4 | 61.9 ± 8.8 |
| Kukreja et al. (15) | USA | PA | 56 (26) | 56 (22) | 58.5 ± 14.8 | 62.1 ± 11.3 |
| Vamshi et al. (11) | India | PA | 30 (20) | 30 (22) | 43.2 ± 13.6 | 41.0 ± 12.7 |
| Ye et al. (13) | China | PLA | 40 (21) | 40 (19) | 52.1 ± 10.8 | 52.3 ± 12.8 |
| Zheng et al. (5) | South Korea | PLA | 25 (15) | 27 (16) | 60.0 ± 10.9 | 63.0 ± 11.7 |
C, control group; GA, general anesthesia; M, male; PA, posterior approach; PAI, the periarticular anesthetic infiltration; PCA, patient-controlled analgesia; PENG, the pericapsular nerve group block; PLA, posterolateral approach; SA, spinal anesthesia; SFIB, the suprainguinal fascia iliaca block; T, treatment group; THA, total hip arthroplasty.
Table 2.
Anesthetic and analgesic protocol followed in the included studies.
| Study | Anesthesia | Peripheral anesthesia | Basic analgesia protocol | Anesthetic cocktail | ||
|---|---|---|---|---|---|---|
| T | C | T | C | |||
| Aliste et al. (9) | SA | PENG | SFIB | PCA (morphine bolus = 1 mg; lockout interval = 8 min), oral acetaminophen (1 g, q6h) and ketoprofen (100 mg, q8h) during 48 h | 20 mL of adrenalized levobupivacaine 0.50% | 40 mL of adrenalized levobupivacaine 0.25% |
| Bravo et al. (27) | SA | PENG | PAI | PCA (morphine bolus = 1 mg; lockout interval = 8 min), oral acetaminophen (1 g, q6h) and ketoprofen (100 mg, q8h) during 48 h | 20 mL of adrenalized bupivacaine 0.50% | 60 mL of adrenalized bupivacaine 0.25% |
| Carella et al. (28) | SA | PENG | SFIB | Intravenous paracetamol (1 g) at the end of the surgery, oral paracetamol (1 g, q6h) and etoricoxib (60 mg, qd), and PCA (0.2% morphine) after surgery | 20 mL of ropivacaine 0.75% | 40 mL of ropivacaine 0.375% |
| Choi et al. (29) | GA | PENG | SFIB | PCA (fentany l7 μg/kg), oral celecoxib (200 mg, q12h), and intravenous acetaminophen (1 g, q12h) | 20 mL of ropivacaine 0.2% with epinephrine 1:200,000 | 30 mL of ropivacaine 0.2% with epinephrine 1:200,000 |
| Domagalska et al. (14) | SA | PENG | Sham | Intravenous acetaminophen (1 g, q6h), metamizole (1 g, q6h), and oral ketorolac (50 mg, q12h) | 20 mL of ropivacaine 0.5% | 20 mL of NaCl 0.9% |
| Et et al. (12) | SA | PENG | PAI | Intravenous paracetamol (1 g, q8h) and oral diclofenac (50 mg, 25 mg ≥75 years, q8h) | 20 mL of bupivacaine 0.5% | 30 mL of 5% bupivacaine with 30 mL of saline |
| Iglesias et al. (30) | SA | PENG | PAI | Oral paracetamol (500 mg, q8h), etoricoxib (60 mg, q12h), and gabapentin (300 mg, qn) | 20 mL of 0.25% bupivacaine with epinephrine | 80 mL of morphine 10 mg, ketorolac 60 mg, and bupivacaine 0.25% with epinephrine |
| Kukreja et al. (15) | SA | PENG | Blank | Oral paracetamol and celecoxib | 25 mL of bupivacaine 0.5% | None |
| Vamshi et al. (11) | GA | PENG | SFIB | PCA (1 mg morphine bolus with a lockout time of 10 min with a maximal dose of 20 mg/4 h), and 1 g intravenous paracetamol (1 g) at 6 h after surgery | 30 mL of bupivacaine 0.25% with clonidine 1 μg/kg | 30 mL of bupivacaine 0.25% with clonidine 1 μg/kg |
| Ye et al. (13) | GA | PENG | PAI | Oral celecoxib (200 mg, q12h) | 20 mL of ropivacaine 0.5% with 1:200,000 adrenaline | 30 mL of ropivacaine 0.33% with 1:200,000 adrenaline |
| Zheng et al. (5) | SA | PENG | PAI | PCA (fentanyl 1,500 μg and ramosetron 0.6 mg), and oral naproxen (VIMOVO® 500/20 mg) | 30 mL of ropivacaine 0.5% | 20 mL of ropivacaine 0.75%, ketorolac 60 mg, and epinephrine 1 g |
C, control group; GA, general anesthesia; PAI, the periarticular anesthetic infiltration; PCA, patient-controlled analgesia; PENG, the pericapsular nerve group block; PLA, posterolateral approach; SA, spinal anesthesia; SFIB, the suprainguinal fascia iliaca block; T, treatment group.
All studies were published in 2021 or later, with eight studies published in 2023 (11, 12, 13, 14, 15, 27, 28, 30). Two studies were performed in Chile (9, 27), and another two in South Korea (5, 29), while one study was performed in each of the following countries: India (11), Turkey (12), China (13), Poland (14), the USA (15), Belgium (28), and Argentina (30).
All adopted a posterior or posterolateral approach during the surgery. Eight studies used spinal anesthesia (5, 9, 12, 14, 15, 27, 28, 30), while the remaining three used general anesthesia (11, 13, 29). A summary of outcome comparisons between patients in the PENG or control arms of the included studies is presented in Table 3.
Table 3.
Summary of outcome comparisons between patients in the PENG or control arms of included studies.
| Study | Outcomes evaluated | Comparison of PENG and control arms |
|---|---|---|
| PENG block vs sham/no block | ||
| Kukreja et al. (15) | Total opioid consumption, pain score, QoR-15, walking distance, complications | PENG block is associated with better recovery and lower opioid consumption within 48 h after surgery, but with similar pain scores and walking distance as control at all time points |
| Domagalska et al. (14) | Total opioid consumption, pain score, quadriceps strength, walking ability | PENG block is associated with lower opioid consumption and pain scores within 72 h after surgery, as well as better leg elevation on the operated hip within 6 h, and walking ability within 10 h |
| PENG block vs SFIB | ||
| Aliste et al. (9) | Total opioid consumption, pain score, motor block, ability to engage in physiotherapy, complications | PENG block is associated with a lower incidence of quadriceps motor block at 3 and 6 h after surgery, better hip adduction at 3 h, but similar analgesia and complications as control |
| Carella et al. (28) | Total opioid consumption, pain score, 2MWT, 6MWT, QoR-15, TUG, complications | PENG block is associated with similar postoperative analgesia and recovery as control |
| Vamshi et al. (11) | Total opioid consumption, pain score, quadriceps weakness, complications | PENG block is associated with lower opioid consumption and pain scores within 48 h after surgery, as well as stronger quadriceps at 6 h after surgery |
| Choi et al. (29) | Total opioid consumption, pain score, quadriceps strength, complications | PENG block is associated with similar opioid consumption, quadriceps strength, complications, and pain scores at all time points as control (except that static pain scores are lower in the PENG group at 6 and 24 h after surgery) |
| PENG block vs PAI | ||
| Bravo et al. (27) | Total opioid consumption, pain score, motor blocks, ability to engage in physiotherapy, complications | PENG block is associated with similar knee extension and hip adduction as PAI, but with higher static pain scores (especially during the first 24 h), and dynamic pain scores (first 6 h) |
| Et et al. (12) | Total opioid consumption, pain score, quadriceps and adductor muscle strength, QoR-40, complications | PENG block is associated with lower dynamic pain scores at 3 and 6 h after surgery, as well as a longer delay until first opioids, but similar functional recovery as PAI. |
| Ye et al. (13) | Total opioid consumption, pain score, hip flexion, quadriceps strength, walking distance, complications | PENG block is associated with similar total opioid consumption, functional recovery, and complications as PAI, but higher dynamic pain scores within 12 h after surgery |
| Zheng et al. (5) | Total opioid consumption, pain score, QoR-40, complications | PENG block is associated with similar pain scores, opioid consumption, functional recovery, and complications as PAI |
| Iglesias et al. (30) | Pain score, motor ability, complications | PENG block is associated with lower opioid consumption than PAI, but with similar motor recovery and complications |
2MWT, 2 min walking test; 6MWT, 6 min walking test; PAI, the periarticular anesthetic infiltration; PENG, the pericapsular nerve group block; QoR-15, quality of recovery-15 questionnaire; QoR-40, quality of recovery-40 questionnaire; SFIB, the suprainguinal fascia iliaca block; THA, total hip arthroplasty; TUG, timed up-and-go test.
Six studies were assessed as being at low risk of bias, three were at unclear risk (11, 28, 30), and another two were at high risk (5, 12) (Fig. 2). The high risk was attributable to a high rate of patient withdrawal for reported pain scores (5), or strong potential for types of bias not directly assessed in the Cochrane tool (12).
Figure 2.
Assessment of the included studies (5, 9, 11, 12, 13, 14, 15, 27, 28, 29, 30). (A) Risk of bias; (B) methodological quality.
Comparison of the PENG block with the sham/no block
Two studies involving 588 patients (14, 15) compared the PENG block to sham/no block in terms of total opioid consumption, postoperative pain scores, and functional recovery. One study (15) also compared them in terms of complications.
Meta-analysis showed that the PENG block was associated with significantly lower total opioid consumption (MD: −25.23, 95% CI: −27.01 to −23.45, I2 = 0%; Fig. 3A). One study (14) reported that the PENG block reduced the rate of intravenous morphine by about 25% and prolonged the mean delay until first opioid consumption by 5 h.
Figure 3.
Forest plot of the meta-analysis of total opioid consumption. (A) PENG block vs sham/no block (14, 15); (B) PENG block vs SFIB (9, 11, 28, 29); (C) PENG block vs PAI (5, 12, 13, 27). SFIB, the suprainguinal fascia iliaca block; PAI, the periarticular anesthetic infiltration.
One study (15) reported no significant differences between study arms in static pain scores upon arrival in the post-anesthesia care unit or at any time between 6 and 48 h after surgery. In contrast, the other study (14) found the PENG block to be associated with significantly lower static and dynamic pain scores at 48, 72, and >72 h after surgery.
One study (15) associated the PENG block with a significantly better quality of recovery (based on the QoR-15 survey), but not greater walking distance. The other study (14) associated the PENG block with a greater frequency of being able to elevate the leg on the operated hip within 6 h after surgery, or being able to walk within 10 h after surgery.
The one study containing data on complications (15) reported that none occurred.
Comparison of the PENG block with the SFIB
Four studies involving 256 patients (9, 11, 28, 29) compared the PENG block to the SFIB in terms of total opioid consumption, postoperative pain scores, functional recovery, and complications.
Meta-analysis associated the PENG block with significantly lower total opioid consumption (MD: −8.25, 95% CI: −16.48 to −0.02, I2 = 68%, Fig. 3B). Sensitivity analysis showed that, except for the study by Aliste et al. (9), the deletion of any other study failed to show a statistically significant difference in total opioid consumption between the two groups.
Meta-analysis showed no significant difference between the study arms in static or dynamic pain scores at time points between 3 and 48 h after surgery (Fig. 4). In addition, one study (28) found no significant difference between the study arms in static or dynamic pain scores at 8:00 h and 13:00 h on postoperative days 1 or 2.
Figure 4.
Forest plot of the meta-analysis of postoperative pain scores between the PENG block and SFIB. (A) Static (9, 28, 29); (B) dynamic (9, 11, 29). SFIB, the suprainguinal fascia iliaca block.
Qualitative analysis of the four studies indicated that the PENG block was at least comparable to the SFIB in terms of functional recovery. Two studies associated the PENG block with a lower incidence of quadriceps weakness or quadriceps motor block after surgery (9, 11), but another study found no significant differences between the study arms in quadriceps strength at any time point between 6 and 48 h after surgery (29). One study (9) linked the PENG block to better preservation of hip adduction at 3 h, but similar proportions of the two study arms were unable to perform physiotherapy on postoperative days 1 or 2 due to motor blockade or pain. Consistently, another study (28) did not observe significant differences between the study arms in the ability to stand up at 6 h after surgery, or in the results of timed ‘up-and-go’, 2 min or 6 min walking tests, or responses on the QoR-15 quality of recovery questionnaire on postoperative days 1 and 2.
The pooled results indicated that the PENG block was noninferior to the SFIB regarding the risk of PONV, urinary retention, respiratory depression, pruritus, and puncture complications after surgery (Table 4).
Table 4.
Outcomes of meta-analyses of complications.
| Complications | Studies | RR (95% CI) | P | I 2 |
|---|---|---|---|---|
| PENG block vs sham/no block | INS | |||
| PENG block vs SFIB | ||||
| PONV | 4 | 1.28 (0.70; 2.34) | 0.54 | 0% |
| Urinary retention | 2 | 3.25 (0.52; 20.29) | 0.2066 | 0% |
| Respiratory depression | 2 | - | - | - |
| Pruritus | 2 | 0.96 (0.26; 3.55) | 0.946 | 0% |
| Puncture complications | 2 | - | - | - |
| PENG block vs PAI | ||||
| PONV | 4 | 0.73 (0.39; 1.38) | 0.3379 | 30% |
| Urinary retention | 2 | 2.9 (0.31; 27.11) | 0.3501 | 0% |
| Respiratory depression | 2 | - | - | - |
| Pruritus | 3 | 1.57 (0.37; 6.63) | 0.5427 | 0% |
| Puncture complications | 1 | - | - | - |
INS, insufficient data for meta-analysis; PAI, the periarticular anesthetic infiltration; PENG, the pericapsular nerve group block; PONV, postoperative nausea and vomiting; SFIB, the suprainguinal fascia iliaca block; RR, relative risk; CI, confidence interval.
Comparison of the PENG block with PAI
A total of five studies involving 290 patients (5, 12, 13, 27, 30) compared the PENG block with PAI in terms of postoperative pain scores, functional recovery, and complications. All but one of the studies, with 40 patients (30), also compared the two techniques in terms of total opioid consumption.
Meta-analysis associated the PENG block with similar total opioid consumption as PAI (MD: −0.95, 95% CI: −3.70 to 1.80, I2 = 34%, Fig. 3C), and with similar static or dynamic pain scores at all postoperative time points, except at 12 h, when the PENG block was associated with higher static pain (SMD: 0.41, 95% CI: 0.08–0.75, I2 = 51%), and at 48 h, when the PENG block was associated with higher dynamic pain (SMD: 0.36, 95% CI: 0.08–0.64, I2 = 0%; Fig. 5).
Figure 5.
Forest plot of the meta-analysis of postoperative pain scores between the PENG block and PAI. (A) Static (5, 12, 13, 27, 30); (B) dynamic (12, 13, 27). PAI, the periarticular anesthetic infiltration.
Furthermore, a sensitivity analysis was conducted on outcomes with heterogeneity greater than 50%. The results of this analysis are presented in Table 5. For static pain scores at 3 and 6 h, the results demonstrated that PAI exhibited a superior analgesic effect compared to the PENG block, with I2 values of 0 and 20%, respectively. For the 12 h static pain score, the I2 value decreased to 49 and 10%, respectively, after the removal of Iglesias et al. and Ye et al. The results demonstrated that PAI was more efficacious than the PENG block or that the two methods exhibited comparable effects. For the 24 h static pain score, although I2 decreased to 0% after the removal of Bravo et al. the results indicated no difference between the two analgesic methods. The sensitivity analysis results for other outcomes with high heterogeneity indicated that I2 remained above 50%. However, the findings showed that the two analgesic methods were equally effective, or that the PAI block was superior to the PENG block.
Table 5.
Outcomes of sensitivity analysis.
| Main source of heterogeneity | SMD (95% CI) | I 2 |
|---|---|---|
| Total opioid consumption (PENG block vs SFIB) | *−8.25 (−16.48 to −0.02) | 68% |
| Vamshi et al. (11) | −4.3 (−10.99 to 2.39) | 32% |
| 6 h static pain score (PENG block vs SFIB) | −0.30 (−0.74 to 0.15) | 55% |
| Choi et al. (29) | −0.09 (−0.42 to 0.24) | 0% |
| 3 h static pain score (PENG block vs PAI) | 0.17 (−0.31 to 0.66) | 69% |
| Et et al. (12) | 0.43 (0.10–0.75) | 0% |
| 6 h static pain score (PENG block vs PAI) | 0.38 (−0.25 to 1.01) | 86% |
| Et et al. (12) | 0.71 (0.41–1.01) | 20% |
| 12 h static pain score (PENG block vs PAI) | 0.41 (0.08–0.75) | 51% |
| Iglesias et al. (30) | 0.5 (0.14–0.86) | 49% |
| Ye et al. (13) | 0.28 (−0.01 to 0.57) | 10% |
| 24 h static pain score (PENG block vs PAI) | 0.23 (−0.10 to 0.57) | 51% |
| Bravo et al. (27) | 0.07 (−0.18 to 0.33) | 0% |
| 12 h dynamic pain score (PENG block vs PAI) | 0.73 (−0.50 to 1.96) | 94% |
| Ye et al. (13) | 0.11 (−0.26 to 0.49) | 6% |
PAI, the periarticular anesthetic infiltration; PENG, the pericapsular nerve group block; SFIB, the suprainguinal fascia iliaca block; SMD, standardized mean difference.
Value is mean difference (95% CI).
Qualitative analysis of the five studies indicated that the PENG block was at least comparable to PAI in terms of functional recovery, based on diverse assessment methods. Two studies reported similar scores on the QoR-40 quality of recovery questionnaire (5, 12), while one of them also reported similar postoperative strength in the quadriceps and adductor muscles (12). Other studies reported no significant differences between study arms in hip flexion, quadriceps muscle strength, or walking distance on postoperative days 1 or 2 (13); similar motor function in the leg on the operated hip (30); or similar incidence of motor block during knee extension or hip adduction at all postoperative time points, with similar proportions of the two study arms unable to perform physiotherapy on postoperative days 1 and 2 due to motor blockade or pain (27).
Meta-analysis indicated that the PENG block was associated with a similar risk of PONV, urinary retention, respiratory depression, pruritus, and puncture complications as PAI (Table 4).
Quality of meta-analytical evidence
The GRADE classification of the results of all meta-analyses can be found in Appendix 2.
Discussion
The PENG block has recently emerged as offering motor-sparing peripheral anesthesia in THA, but conflicting analyses of its efficacy have hindered its broader implementation. Our results suggest that the PENG block is an effective alternative to the SFIB or PAI for patients undergoing THA, though further work is needed to determine whether it is superior to the SFIB or PAI.
No studies have meta-analyzed the efficacy of the PENG block versus sham/no block. The available evidence indicates that the PENG block has a positive effect on total opioid consumption and the time to first opioid use. However, for static pain, the PENG block’s analgesic effect does not appear significant. Although Domagalska et al. (14) reported a statistically significant difference between the PENG block and sham block at 72 h postoperatively, we found that the difference in pain scores was less than 1 point. Given that pain is a subjective sensation, a difference in pain scores of less than 1 point may not be perceived as significant by the patient. The dynamic pain reported by Domagalska et al. (14) demonstrated statistical significance over the monitored timeframe, with a difference in pain scores exceeding 1 point. Regrettably, Kukreja et al. (15) did not report the results of the dynamic pain outcomes. In terms of functional recovery, the two available studies demonstrated beneficial effects. Therefore, we hypothesized that the benefits of the PENG block might be shown in terms of reduced total opioid consumption, delayed time to first opioid use, and dynamic pain control. Dynamic pain control is closely related to early functional recovery.
The findings of this study indicated that the PENG block was more effective than the SFIB in reducing total opioid consumption, but 68% heterogeneity was observed. Further sensitivity analyses demonstrated a reduction in heterogeneity following the exclusion of the study by Vamshi et al. (11). We hypothesized that this may be related to the younger age of the subjects in that study. Regarding pain and functional recovery, our findings indicated that the PENG block was noninferior to the SFIB. We observed that the heterogeneity of the results of several pain-related meta-analyses exceeded 50%, which might stem from differences in population characteristics and anesthetic drugs among different studies. From an anatomical perspective, local anesthesia does not spread to the obturator nerve when performing the SFIB. (11) This may explain the retention of motion observed with the PENG block, as the PENG block can target the obturator nerve, thereby providing superior pain control. However, with the PENG block, diffusion of local anesthetic to the femoral nerve may weaken the quadriceps muscle (31, 32), while certain injection positions or large injection volumes can weaken the adductor muscle (33).
In comparison to PAI, which is popular because of its relative ease and low risk of adverse events, our results show that the PENG block was at least comparable to PAI in terms of total opioid consumption, pain scores, and functional recovery based on diverse assessment methods. Although there are differences in static pain scores at 12 h and dynamic pain scores at 48 h, the small statistical differences at limited time points are unlikely to translate into clinical significance in pain assessment. Thus, our results suggest that the two techniques, both of which are valued because they spare motor function, may offer comparable pain control. Similarly, the high heterogeneity of the results of pain-related meta-analyses may stem from the differences in population characteristics and anesthetic drugs among different studies. PAI distributes local anesthetic over a wider range than the PENG block, including the joint capsule, muscles, peritrochanteric area, and subcutaneous tissue (13), yet it may lead to insufficient infiltration of anesthetic into the anterior hip capsule during traditional posterior or posterolateral THA. The anterior hip capsule contains significantly more sensory nerve endings than the posterior hip capsule (34). In other words, PAI acts primarily on the posterior capsule, while the PENG block acts mainly from the anterior capsule. Given our finding that the PENG block and PAI also offer comparable functional recovery, whether in terms of quadriceps strength or functional performance, clinicians and researchers should continue to explore the combined use of the PENG block and PAI because of their complementary sites of action (24, 25, 35). The PENG block and PAI offer comparable pain control and functional recovery in THA; therefore, exploring their combined use is recommended to leverage their complementary benefits.
Our study has several limitations. First, the major one is that studies differed in the approach used for THA, the type of anesthesia, and the basic analgesic protocol. We compensated for this heterogeneity using random-effects models in all meta-analyses, but we could not perform subgroup analysis to assess the impact of these parameters on the results due to the lack of available data. Similarly, the available data in randomized controlled trials are insufficient to determine optimal puncture-related parameters in the PENG block, which affect analgesic and functional outcomes. Second, we did not meta-analyze data on the efficacy of the plexus nerve block in one included study (30) or the quadratus lumborum block in another study (12). Future work should compare the PENG block with these types of anesthesia. Third, whether our meta-analysis can be generalized to THA via the anterior approach is unclear, since all studies in our review applied the traditional posterior or posterolateral approach. Fourth, evaluating long-term effects is essential for fully understanding the impact of the PENG block. Due to limited data availability, our meta-analysis focused on short-term effects up to 48 h, as most studies lack reliable long-term data beyond this timeframe. Thus, we need to focus on observing the PENG block’s long-term effects, hoping to gain more insights and overcome this limitation in future research. Furthermore, our analysis is restricted by the number of included trials in each subgroup, which leads to insufficient statistical power. Therefore, although our research findings provide preliminary evidence, they should be interpreted with caution until they are verified in more well-designed studies. Finally, baseline differences among studies (countries, potential social differences, mobilization strategies and length of stay) may cause biases in the results, but we do not have sufficient data to conduct relevant subgroup analyses.
Conclusion
The current evidence from randomized controlled trials suggests that the PENG block is a viable and effective option compared to the SFIB or PAI for patients undergoing THA. However, the limited sample size of each subgroup has led to inadequate statistical power, which makes it impossible for us to definitively establish whether the PENG block has superiority over the SFIB or PAI in terms of pain management and functional recovery. More high-quality randomized controlled trials are needed to confirm its equivalence or potential superiority. Thus, the most appropriate type of peripheral anesthesia can be selected based on clinician skill, patient characteristics, and other contextual factors. Combinations of these blocks should be considered if necessary. These deliberations should also take into account that the PENG block can be delivered while the patient is supine, which may be particularly advantageous in the event of femoral neck fracture, ankylosed hip, or severe hip pain. Future research is urgently needed to develop guidelines on the technical parameters of the PENG block to optimize its efficacy.
Supplementary materials
ICMJE Statement of Interest
The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the work reported.
Funding Statement
The current project is supported by the ‘Traditional Chinese Medicine Evidence-Based Capacity Building Project (2019XZZX-GK004)’ of the State Administration of Traditional Chinese Medicine.
Author contribution statement
YPL and FL searched the literature and extracted data. YPL and QYW analyzed the data. CY and YPL wrote the manuscript. ZJZ and CY conceived the idea. JYG reviewed the manuscript.
Data sharing
The data can be obtained by contacting the corresponding author.
Registration
This meta-analysis was registered on PROSPERO (Registration number: CRD42023470161).
Acknowledgments
We thank Professor Qiao Hang from the Evidence-Based and Translational Medicine Center of Zhongnan Hospital of Wuhan University for methodology support, Professor Jiaguo Zhao from the orthopedic department of Beijing Tongren Hospital Affiliated with Capital Medical University for valuable discussions, and A. Chapin Rodríguez, PhD, for English language editing.
References
- 1.Shichman I, Roof M, Askew N, et al. Projections and epidemiology of primary hip and knee arthroplasty in medicare patients to 2040–2060. JB JS Open Access 2023. 8 e22.00112. ( 10.2106/jbjs.oa.22.00112) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Wainwright TW, Gill M, McDonald DA, et al. Consensus statement for perioperative care in total hip replacement and total knee replacement surgery: enhanced recovery after surgery (ERAS®) society recommendations. Acta Orthop 2020. 91 363. ( 10.1080/17453674.2020.1724674) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Anger M, Valovska T, Beloeil H, et al. PROSPECT guideline for total hip arthroplasty: a systematic review and procedure-specific postoperative pain management recommendations. Anaesthesia 2021. 76 1082–1097. ( 10.1111/anae.15498) [DOI] [PubMed] [Google Scholar]
- 4.Gao Y, Tan H, Sun R, et al. Fascia iliaca compartment block reduces pain and opioid consumption after total hip arthroplasty: a systematic review and meta-analysis. Int J Surg 2019. 65 70–79. ( 10.1016/j.ijsu.2019.03.014) [DOI] [PubMed] [Google Scholar]
- 5.Zheng L, Jo Y, Hwang J, et al. Comparison of the analgesic efficacy of periarticular infiltration and pericapsular nerve group block for total hip arthroplasty: a randomized, non-inferiority study. Ann Palliat Med 2022. 11 1222–1230. ( 10.21037/apm-21-2785) [DOI] [PubMed] [Google Scholar]
- 6.den Hartog YM, Mathijssen NMC, van Dasselaar NT, et al. No effect of the infiltration of local anaesthetic for total hip arthroplasty using an anterior approach: a randomised placebo controlled trial. Bone Joint Lett J 2015. 97-B 734–740. ( 10.1302/0301-620x.97b6.35343) [DOI] [PubMed] [Google Scholar]
- 7.Hirasawa N, Kurosaka K, Nishino M, et al. No clinically important difference in pain scores after THA between periarticular analgesic injection and placebo: a randomized trial. Clin Orthop Relat Res 2018. 476 1837–1845. ( 10.1097/corr.0000000000000374) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Zoric L, Cuvillon P, Alonso S, et al. Single-shot intraoperative local anaesthetic infiltration does not reduce morphine consumption after total hip arthroplasty: a double-blinded placebo-controlled randomized study. Br J Anaesth 2014. 112 722–728. ( 10.1093/bja/aet439) [DOI] [PubMed] [Google Scholar]
- 9.Aliste J, Layera S, Bravo D, et al. Randomized comparison between pericapsular nerve group (PENG) block and suprainguinal fascia iliaca block for total hip arthroplasty. Reg Anesth Pain Med 2021. 46 874–878. ( 10.1136/rapm-2021-102997) [DOI] [PubMed] [Google Scholar]
- 10.Girón-Arango L, Peng PWH, Chin KJ, et al. Pericapsular nerve group (PENG) block for hip fracture. Reg Anesth Pain Med 2018. 43 859–863. ( 10.1097/AAP.0000000000000847) [DOI] [PubMed] [Google Scholar]
- 11.Vamshi C, Sinha C, Kumar A, et al. Comparison of the efficacy of pericapsular nerve group block (PENG) block versus suprainguinal fascia iliaca block (SFIB) in total hip arthroplasty: a randomized control trial. Indian J Anaesth 2023. 67 364–369. ( 10.4103/ija.ija_311_22) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Et T & Korkusuz M. Comparison of the pericapsular nerve group block with the intra-articular and quadratus lumborum blocks in primary total hip arthroplasty: a randomized controlled trial. Korean J Anesthesiol 2023. 76 575–585. ( 10.4097/kja.23064) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Ye S, Wang L, Wang Q, et al. Comparison between ultrasound-guided pericapsular nerve group block and local infiltration analgesia for postoperative analgesia after total hip arthroplasty: a prospective randomized controlled trial. Orthop Surg 2023. 15 1839–1846. ( 10.1111/os.13777) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Domagalska M, Ciftci B, Reysner T, et al. Pain management and functional recovery after pericapsular nerve group (PENG) block for total hip arthroplasty: a prospective, randomized, double-blinded clinical trial. J Clin Med 2023. 12 4931. ( 10.3390/jcm12154931) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Kukreja P, Uppal V, Kofskey AM, et al. Quality of recovery after pericapsular nerve group (PENG) block for primary total hip arthroplasty under spinal anaesthesia: a randomised controlled observer-blinded trial. Br J Anaesth 2023. 130 773–779. ( 10.1016/j.bja.2023.02.017) [DOI] [PubMed] [Google Scholar]
- 16.Kim E, Shin WC, Lee SM, et al. Efficacy of pericapsular nerve group block for pain reduction and opioid consumption after total hip arthroplasty: a meta-analysis of randomized controlled trials. Hip Pelvis 2023. 35 63–72. ( 10.5371/hp.2023.35.2.63) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Huda AU & Ghafoor H. The use of pericapsular nerve group (PENG) block in hip surgeries is associated with a reduction in opioid consumption, less motor block, and better patient satisfaction: a meta-analysis. Cureus 2022. 14 e28872. ( 10.7759/cureus.28872) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Int J Surg 2021. 88 105906. ( 10.1016/j.ijsu.2021.105906) [DOI] [PubMed] [Google Scholar]
- 19.Shea BJ, Reeves BC, Wells G, et al. Amstar 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. BMJ 2017. 358 j4008. ( 10.1136/bmj.j4008) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Nielsen S, Degenhardt L, Hoban B, et al. A synthesis of oral morphine equivalents (OME) for opioid utilisation studies. Pharmacoepidemiol Drug Saf 2016. 25 733–737. ( 10.1002/pds.3945) [DOI] [PubMed] [Google Scholar]
- 21.Lefebvre C, Glanville J, Briscoe Set al. Searching for and selecting studies. In: Cochrane Handbook for Systematic Reviews of Interventions. Higgins JPT, Thomas J, Chandler Jet al. (Eds.) version 6.5 (updated August 2024). Cochrane, 2024. Available from www.training.cochrane.org/handbook [Google Scholar]
- 22.Higgins JPT & Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med 2002. 21 1539–1558. ( 10.1002/sim.1186) [DOI] [PubMed] [Google Scholar]
- 23.Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ 2008. 336 924–926. ( 10.1136/bmj.39489.470347.ad) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Pascarella G, Costa F, Del Buono R, et al. Impact of the pericapsular nerve group (PENG) block on postoperative analgesia and functional recovery following total hip arthroplasty: a randomised, observer-masked, controlled trial. Anaesthesia 2021. 76 1492–1498. ( 10.1111/anae.15536) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Zheng J, Pan D, Zheng B, et al. Preoperative pericapsular nerve group (PENG) block for total hip arthroplasty: a randomized, placebo-controlled trial. Reg Anesth Pain Med 2022. 47 155–160. ( 10.1136/rapm-2021-103228) [DOI] [PubMed] [Google Scholar]
- 26.Duan L, Zhang L, Shi CG, et al. Comparison of continuous pericapsular nerve group (PENG) block versus continuous fascia iliaca compartment block on pain management and quadriceps muscle strength after total hip arthroplasty: a prospective, randomized controlled study. BMC Anesthesiol 2023. 23 233. ( 10.1186/s12871-023-02190-1) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Bravo D, Aliste J, Layera S, et al. Randomized clinical trial comparing pericapsular nerve group (PENG) block and periarticular local anesthetic infiltration for total hip arthroplasty. Reg Anesth Pain Med 2023. 48 489–494. ( 10.1136/rapm-2023-104332) [DOI] [PubMed] [Google Scholar]
- 28.Carella M, Beck F, Piette N, et al. Comparison between supra-inguinal fascia iliaca and pericapsular nerve group blocks on postoperative pain and functional recovery after total hip arthroplasty: a noninferiority randomised clinical trial. Eur J Anaesthesiol 2023. 40 660–671. ( 10.1097/eja.0000000000001875) [DOI] [PubMed] [Google Scholar]
- 29.Choi YS, Park KK, Lee B, et al. Pericapsular nerve group (PENG) block versus supra-inguinal fascia iliaca compartment block for total hip arthroplasty: a randomized clinical trial. J Pers Med 2022. 12 408. ( 10.3390/jpm12030408) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Iglesias SL, Nieto I, López P, et al. Pericapsular nerves block (PENG) is an effective and safe alternative for postoperative pain management after primary total hip arthroplasty: a randomised clinical trial. Rev Esp Cir Ortop Traumatol 2023. 67 T226–T232. ( 10.1016/j.recot.2023.02.021) [DOI] [PubMed] [Google Scholar]
- 31.Lin DY, Morrison C, Brown B, et al. Pericapsular nerve group (PENG) block provides improved short-term analgesia compared with the femoral nerve block in hip fracture surgery: a single-center double-blinded randomized comparative trial. Reg Anesth Pain Med 2021. 46 398–403. ( 10.1136/rapm-2020-102315) [DOI] [PubMed] [Google Scholar]
- 32.Yu HC, Moser JJ, Chu AY, et al. Inadvertent quadriceps weakness following the pericapsular nerve group (PENG) block. Reg Anesth Pain Med 2019. 44 611–613. ( 10.1136/rapm-2018-100354) [DOI] [PubMed] [Google Scholar]
- 33.Girón-Arango L, Tran J & Peng PW. Reply to Aydin et al.: a Novel Indication of Pericapsular Nerve Group Block: surgical Anesthesia for Vein Ligation and Stripping. J Cardiothorac Vasc Anesth 2020. 34 845–846. ( 10.1053/j.jvca.2019.10.027) [DOI] [PubMed] [Google Scholar]
- 34.Tomlinson J, Zwirner J, Ondruschka B, et al. Innervation of the hip joint capsular complex: a systematic review of histological and immunohistochemical studies and their clinical implications for contemporary treatment strategies in total hip arthroplasty. PLoS One 2020. 15 e0229128. ( 10.1371/journal.pone.0229128) [DOI] [PMC free article] [PubMed] [Google Scholar]
- 35.Lin DY, Brown B, Morrison C, et al. The pericapsular nerve group (PENG) block combined with local infiltration analgesia (LIA) compared to placebo and LIA in hip arthroplasty surgery: a multi-center double-blinded randomized-controlled trial. BMC Anesthesiol 2022. 22 252. ( 10.1186/s12871-022-01787-2) [DOI] [PMC free article] [PubMed] [Google Scholar]
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