Pericapsular nerve group block combined with lateral femoral cutaneous nerve block versus fascia iliaca compartment block for hip surgery: a systematic review, meta-analysis, and trial sequential analysis

Abstract

Background

The combination of the pericapsular nerve group (PENG) and lateral femoral cutaneous nerve (LFCN) blocks has been proposed as a motor-sparing alternative to the fascia iliaca compartment block (FICB) for analgesia after hip surgery. However, previous reviews were limited by insufficient data to draw definitive conclusions regarding this specific combination.

Methods

The authors conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing PENG plus LFCN versus FICB. They searched PubMed, Scopus, Embase, Cochrane CENTRAL, and Web of Science. Risk of bias was assessed using the Cochrane Risk of Bias 2 tool. Data were synthesized using a random-effects model in accordance with PRISMA.

Results

Six RCTs (442 patients) were included in the analysis. PENG + LFCN significantly reduced resting pain scores at 6 hours (mean difference [MD] –0.72; 95% confidence interval [CI] –1.28 to –0.16; P = 0.012) and at 24 hours (MD –0.91; 95% CI –1.59 to –0.23; P = 0.009) compared with FICB. The combined block also demonstrated superior preservation of motor function with higher quadriceps muscle strength grades at 6 hours (MD 1.10; P < 0.001) and 24 hours (MD 0.89; P = 0.012), and a lower incidence of muscle weakness at 6 hours (risk ratio 0.10; P = 0.005). The time to ambulation was significantly shorter. There was no significant difference in opioid consumption or in the incidence of nausea and vomiting.

Conclusions

PENG plus LFCN provides superior analgesia and motor preservation compared with FICB, facilitating early ambulation and optimizing functional recovery.

INTRODUCTION

Effective management of postoperative pain following hip and proximal femur surgery remains a significant perioperative challenge [1,2]. Severe pain may delay functional rehabilitation, prolong hospital stay, and increase the risk of complications such as deep vein thrombosis [3,4]. Inadequate pain control is also associated with increased opioid consumption and related adverse effects, including nausea, vomiting, delirium, and respiratory depression [5]. In this context, multimodal analgesia, which integrates pharmacological strategies with regional nerve blocks, aims to reduce opioid requirements while providing effective analgesia [2].

Among regional techniques, the pericapsular nerve group (PENG) block targets the articular branches of the femoral, obturator, and accessory obturator nerves, providing analgesia to the anterior hip capsule without significant motor impairment and thereby facilitating early ambulation [6]. The lateral femoral cutaneous nerve (LFCN) block, which arises from the lumbar plexus and has a variable anatomical course, provides sensory coverage of the anterolateral thigh and has been shown to reduce movement-related pain after total hip arthroplasty (THA), although it may not adequately cover the entire surgical incision [7–10]. The fascia iliaca compartment block (FICB), in contrast, is widely used for hip and proximal femur surgery but is frequently associated with quadriceps weakness [11,12].

The combined use of the PENG and LFCN blocks has been proposed as a promising perioperative analgesic strategy, with the potential to reduce opioid consumption and enhance early mobilization [13,14]. Although the PENG block, alone or combined with local infiltration analgesia, is increasingly recognized as an effective technique for THA, consolidated evidence regarding the specific combination of the PENG and LFCN blocks remains limited. Notably, previous network meta-analyses lacked sufficient data to draw definitive conclusions regarding this combination. Therefore, this systematic review and meta-analysis aims to compare combined PENG and LFCN blockade with the FICB in hip and proximal femur surgery, evaluating postoperative pain, opioid consumption, motor function, and adverse events [15,16].

MATERIALS AND METHODS

This systematic review was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [17]. The protocol was prospectively registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD420251110488).

1. Eligibility criteria

Eligibility criteria were defined according to the PICOS framework: (P) adult patients (≥ 18 years) undergoing hip or proximal femur surgery, including plate or intramedullary nail fixation, arthroscopy, and total or partial hip arthroplasty; (I) combined PENG and LFCN block; (C) isolated FICB; (O) analgesia-related outcomes; and (S) randomized controlled trials (RCTs). Exclusion criteria included pediatric populations, observational studies, case reports, narrative or systematic reviews, and trials with incomplete or irretrievable data. Studies evaluating PENG block alone, PENG block combined with techniques other than LFCN block, or FICB combined with additional interventions were also excluded.

2. Search strategy

A systematic literature search was conducted in PubMed, Scopus, Embase, Cochrane CENTRAL, and Web of Science from database inception to July 22, 2025 without restrictions on publication year. The search strategy combined terms related to hip or proximal femur surgery, pericapsular nerve block, LFCN block, and FICB using appropriate Boolean operators. The complete search strategy is provided in the supplementary material (Supplementary Table 1).

3. Study selection

Two reviewers independently screened titles and abstracts for eligibility, followed by full-text assessment of potentially relevant studies. Disagreements were resolved through discussion or, when necessary, by consultation with a third reviewer.

4. Data extraction

Data extraction was independently performed by two reviewers using a standardized spreadsheet in Microsoft Excel® (version 2205). Extracted data included study author, publication year, country, study design, sample size, participant age range, type of surgery and surgical approach, characteristics of the intervention (PENG plus LFCN block) and comparator (FICB), outcomes assessed, and duration of follow-up. Discrepancies were resolved by a senior reviewer after verification against the original publications.

5. Risk of bias assessment

The risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, which evaluates five domains: randomization process, deviations from intended interventions, missing outcome data, outcome measurement, and selection of the reported result [18]. Each domain was rated as “low risk,” “some concerns,” or “high risk,” leading to an overall judgment for each study. Assessments were conducted independently by two reviewers, with disagreements resolved by consensus. Publication bias was assessed using funnel plots and Egger’s regression test [19,20].

6. Outcomes assessed

The primary outcomes were resting/dynamic pain scores, expressed by the Numerical Rating Scale (NRS), at 6 and 24 hours postoperatively. Secondary outcomes included total opioid consumption within the first 24 hours (expressed as oral morphine milligrams equivalents), the incidence of postoperative nausea and vomiting (PONV), quadriceps muscle strength scores (assessed by the manual muscle test [MMT]), and the incidence of muscle weakness at 6 and 24 hours, and the time to ambulation in hours.

7. Statistical analysis

All statistical analyses were performed using R software (version 4.5.1; R Foundation for Statistical Computing) with the “meta” package. A random-effects model with restricted maximum likelihood was applied to account for anticipated clinical and methodological heterogeneity. Risk ratios (RRs) were calculated for binary outcomes, and mean differences (MDs) for continuous outcomes, each with corresponding 95% confidence intervals (CIs). Statistical significance was defined as P < 0.05. Heterogeneity was evaluated using the I² statistic and Cochran’s Q test, with substantial heterogeneity defined as an I² > 50% and a Q-test P value < 0.05.

The robustness of pooled estimates was examined using leave-one-out sensitivity analyses. Prespecified subgroup analyses explored potential sources of heterogeneity related to surgical procedure (hip fracture vs. THA), anesthetic regimen (spinal anesthesia with vs. without intrathecal opioids), FICB technique (traditional vs. suprainguinal), and injectate volume (20 mL vs. 25–35 mL). An additional sensitivity analysis was conducted restricting the dataset to studies at low risk of bias.

When outcomes were reported as medians and interquartile ranges, values were converted to means and standard deviations using the methods described by Luo et al. [21] and Wan et al. [22]. Pain scores measured by the Visual Analog Scale were converted to the equivalent NRS, due to their high correlation, and reported as such (0 to 10 scale with 0 representing absence of pain and 10, the worst pain imaginable) [23]. Opioid consumption was standardized to oral morphine equivalents (MME) using the validated conversion calculator from the Faculty of Pain Medicine of the Australian and New Zealand College of Anaesthetists [24]. Quadriceps muscle strength was measured and expressed by the MMT, which grades the muscle response in 0 to 5 scale (0 representing absence of visible or palpable contraction, 1 to visible or palpable contraction without joint motion, 2 to muscle contraction that could only induce horizontal joint movement, 3 when capable of lifting the leg and extending the knee under gravity but unable to resist resistance, 4 when capable of lifting the leg and extending the knee against gravity and moderate resistance, and 5 representing normal in power against gravity and full resistance). Quadriceps muscle weakness was defined as a MMT grade below 3.

8. Trial sequential analysis

Trial Sequential Analysis (TSA) ([Computer program]; version 0.9.5.10 Beta. The Copenhagen Trial Unit, Centre for Clinical Intervention Research, The Capital Region, Copenhagen University Hospital– Rigshospitalet, 2021) was performed to evaluate the adequacy of cumulative evidence and to minimize the risk of random errors due to repeated significance testing [25]. Prespecified intervention effects consisted of reductions in the relative risk of complications (50%), postoperative pain scores (1 point), opioid consumption (10 mg), and time to ambulation (3 hours), as well as a 1-point increase in muscle strength grades, based on findings from initial studies at low risk of bias [14,26]. Two-sided tests were applied with a type I error of 5% (α = 0.05) and a type II error of 20% (β = 0.20), corresponding to 80% power.

Conventional significance boundaries and trial sequential monitoring boundaries were constructed. Heterogeneity adjustment was performed using the variance estimated from the DerSimonian and Laird random-effects model. Cumulative Z-curves were plotted, and the diversity-adjusted required information size (RIS) was calculated. Crossing the monitoring boundaries indicated firm evidence for an intervention effect, whereas results within the futility zone suggested a lack of clinically relevant benefit.

9. Certainty of evidence

The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework via the GRADEpro platform (https://www.gradepro.org) [27]. The evaluation considered risk of bias, consistency, precision, applicability, and overall methodological rigor of the included studies.

RESULTS

1. Study selection

The database search identified 224 records. After removal of duplicates, 174 articles remained for screening. Following title and abstract review, 167 records were excluded, leaving seven studies for full-text eligibility assessment. Of these, six studies met the inclusion criteria and were included in the final analysis [13,14,26,28–30]. One study was excluded because it used local infiltration analgesia as the comparator rather than the FICB [31]. The study selection process is summarized in Fig. 1.

Fig. 1.

Flowchart of study screening and selection (PRISMA).

2. Study characteristics

Three studies included patients undergoing THA, with a direct anterior approach used in one study and a posterolateral approach in the remaining two [26,28,30]. Two studies enrolled patients with proximal femur fractures [13,29], and one evaluated patients undergoing hip arthroscopy [14]. Regarding anesthetic technique, three studies used spinal anesthesia with hyperbaric bupivacaine combined with intrathecal adjuvants (sufentanil, fentanyl, or buprenorphine) [13,26,29], whereas the remaining studies employed general, total intravenous, or balanced anesthesia [14,28,30].

Block performance was consistent across studies. The PENG block was performed under ultrasound guidance in the plane between the psoas tendon and the pubic ramus; the LFCN block was administered between the sartorius and tensor fasciae latae muscles near the anterior superior iliac spine; and the FICB was performed using a suprainguinal approach, with injection between the fascia iliaca and the iliopsoas muscle [13,14,26,28–30].

Variations were observed in the local anesthetic agents and volumes used. Most studies administered ropivacaine (0.33%–0.5%) [14,26,28–30], whereas others used 0.25% bupivacaine [13,29], which in one study was combined with dexamethasone [29]. The volume administered for the PENG block ranged from 20 to 35 mL, for the LFCN block from 3 to 10 mL, and for the FICB from 20 to 40 mL, according to individual study protocols. Detailed characteristics of the included studies are presented in Table 1.

Table 1.

Characteristics of the included studies

Author; country	Total sample	Age (yr), mean ± SD	Type of surgery	Intervention (PENG + LFCN)	Comparator (FICB)	Outcome
Vetrone et al. [26], 2025; Italy	58 (PENG + LFCN = 29/ FICB = 29)	PENG + LFCN = 71 ± 10/ FICB = 71 ± 9	Total hip arthroplasty	Spinal anesthesia with 0.5% hyperbaric bupivacaine (0.06 mg/cm) + 5 µg intrathecal sufentanil; ultrasound-guided PENG (20 mL of 0.5% ropivacaine) and LFCN (10 mL of 0.5% ropivacaine) blocks.	Spinal anesthesia with 0.5% hyperbaric bupivacaine (0.06 mg/cm of height) + 5 µg intrathecal sufentanil; ultrasound-guided FICB/S-FICB (20 mL of 0.5% ropivacaine) block.	Quadriceps weakness at 6 hours post-block. Degree of active hip flexion (muscle strength and pain), perioperative analgesic efficacy, opioid consumption, adverse events (nausea and vomiting), and time to ambulation.
Tian et al. [30], 2025; China	60 (PENG + LFCN = 30/ FICB = 30)	PENG + LFCN = 63.57 ± 12.41/ FICB = 62.90 ± 13.45	Total hip arthroplasty	Intravenous general anesthesia; ultrasound-guided PENG (20 mL of 0.4% ropivacaine) and LFCN (3 mL of 0.4% ropivacaine) blocks.	Intravenous general anesthesia: midazolam 0.03 mg/kg, propofol 2 mg/kg, cisatracurium 0.2 mg/kg, and sufentanil 0.3 μg/kg; anesthesia maintained with continuous pump infusions of propofol and remifentanil. Ultrasound-guided S-FICB block: 40 mL of 0.4% ropivacaine.	Muscle strength, analgesia, motor function. Pain during the first 48 hours, muscle strength (quadriceps femoris and adductor), extent of sensory block, length of hospital stay, and complications.
Shalaby et al. [13], 2022; Egypt	94 (PENG + LFCN = 48/ FICB = 46)	Not reported	Proximal femur fracture surgery	Spinal anesthesia with 0.5% hyperbaric bupivacaine (3 mL) + 20 µg intrathecal fentanyl; ultrasound-guided PENG (25 mL of 0.25% bupivacaine) and LFCN (5 mL of 0.25% bupivacaine) blocks.	Spinal anesthesia: 3 mL of 0.5% hyperbaric bupivacaine + 20 μg intrathecal fentanyl. Ultrasound-guided S-FICB block: 30 mL of 0.25% bupivacaine; suprainguinal approach, 1 cm cephalad to the anterior superior iliac spine, superficial to the fascia iliaca.	Analgesic effect, surgical positioning, anesthesia performance time. Assessment of sensory block, pain scores during spinal anesthesia, anesthesiologist satisfaction, time to first analgesic request, postoperative pain score, total morphine consumption, and adverse effects.
Liu et al. [14], 2024; China	78 (PENG + LFCN = 39/ FICB = 39)	PENG + LFCN = 44.1 ± 13.7/ FICB = 39.3 ± 17.7	Hip arthroscopy	General anesthesia with 0.05 mg/kg midazolam, 2 mg/kg propofol, 0.3 µg/kg sufentanil, and 0.2 mg/kg cisatracurium IV; maintenance with continuous infusions of propofol (3–6 mg/kg/h) and remifentanil (0.1–0.4 µg/kg/h); ultrasound-guided PENG (35 mL of 0.375% ropivacaine) and LFCN (5 mL of 0.375% ropivacaine) blocks.	Intravenous general anesthesia: midazolam 0.05 mg/kg, propofol 2 mg/kg, sufentanil 0.3 μg/kg, and cisatracurium 0.2 mg/kg; maintenance with continuous infusions of propofol (3–6 mg/kg/h) and remifentanil (0.1–0.4 μg/kg/h). Ultrasound-guided FICB block: 40 mL of 0.375% ropivacaine.	Quadriceps weakness, muscle strength grading, pain scores, and recovery at 48 hours. Analgesic consumption, duration of sensory block, mobilization and ambulation, sleep quality, and postoperative complications.
Liang et al. [28], 2023; China	92 (PENG + LFCN = 46/ FICB = 46)	PENG + LFCN = 66.7 ± 14.4/ FICB = 67.3 ± 10.2	Total hip arthroplasty	General anesthesia with 10 mg IV dexamethasone preoperatively; induction with propofol (2.0–2.5 mg/kg), sufentanil (0.4–0.5 µg/kg), and vecuronium (0.1 mg/kg); maintenance with propofol (2–5 mg/kg/h), remifentanil (0.1–0.5 µg/kg/min), and sevoflurane (1%–2%); ultrasound-guided PENG (20 mL of 0.33% ropivacaine) and LFCN (10 mL of 0.33% ropivacaine) blocks.	Intravenous general anesthesia: premedication with 10 mg IV dexamethasone; induction with propofol (2.0–2.5 mg/kg), sufentanil (0.4–0.5 μg/kg), and vecuronium (0.1 mg/kg); maintenance with propofol (2–5 mg/kg/h), remifentanil (0.1–0.5 μg/kg/min), and sevoflurane (1%–2%). Ultrasound-guided S-FICB block: 30 mL of 0.33% ropivacaine.	Time to first ambulation. Intraoperative remifentanil consumption, pain scores, rescue analgesia, postoperative quadriceps strength, PONV, and nerve block-related complications.
Aravind et al. [29], 2025; India	60 (PENG + LFCN = 30/ FICB = 30)	PENG + LFCN = 73.7/ FICB = 74.0 (mean only, no ± SD)	Hip fracture surgery (femoral neck, intertrochanteric, and subtrochanteric)	Spinal anesthesia with 0.5% hyperbaric bupivacaine (2.8 mL) + 60 µg intrathecal buprenorphine; ultrasound-guided PENG (20 mL of 0.25% bupivacaine + 8 mg dexamethasone) and LFCN (5 mL of 0.25% bupivacaine) blocks.	Spinal anesthesia: 2.8 mL of 0.5% hyperbaric bupivacaine + 60 μg of buprenorphine as an adjuvant; subarachnoid block performed with a 25G Quincke spinal needle. Ultrasound-guided FICB block: 25 mL of 0.25% bupivacaine + 8 mg dexamethasone.	Duration of postoperative analgesia, pain scores, and the need for systemic analgesics. Ease of positioning, patient satisfaction, and recovery of quadriceps muscle strength.

SD: standard deviation, PENG: pericapsular nerve group, LFCN: lateral femoral cutaneous nerve, FICB: fascia iliaca compartment block, S-FICB: suprainguinal FICB, IV: intravenous, PONV: postoperative nausea and vomiting.

3. Risk of bias

Assessment using the RoB 2 tool indicated an overall low to moderate risk of bias across the included studies (Fig. 2). All trials demonstrated adequate randomization and no evidence of selective outcome reporting. Two studies were rated as having “some concerns” because of the lack of blinding of participants and personnel, which may have led to deviations from intended interventions [13,28]. Two additional studies presented similar concerns due to the absence of outcome assessor blinding, potentially influencing the measurement of subjective outcomes [29,30]. One study was judged to be at risk of bias due to missing outcome data resulting from exclusion of failed blocks from the final analysis [13].

Fig. 2.

Risk of bias assessment of the included studies.

4. Pooled analysis

Resting postoperative pain intensity at 6 hours was significantly lower in patients receiving the combined PENG and LFCN block compared with FICB (NRS MD −0.72; 95% CI −1.28 to −0.16; P = 0.012; I² = 66.9%; Fig. 3A). A similar effect was observed at 24 hours (NRS MD −0.91; 95% CI −1.59 to −0.23; P = 0.009; I² = 84.8%; Fig. 3B). Dynamic postoperative pain, 6 hours after surgery, was reduced in patients who received both PENG and LFCN, but statistically insignificantly (NRS MD –0.73; 95% CI –1.49 to 0.03; P = 0.061; Fig. 3C). For dynamic pain at 24 hours, there was no significant difference (Fig. 3D).

Fig. 3.

Forest plot of mean resting pain intensity measured using the Numerical Rating Scale at (A) 6 hours and (B) 24 hours postoperatively. Dynamic postoperative pain score at (C) 6 hours and (D) 24 hours. PENG: pericapsular nerve group, LFCN: lateral femoral cutaneous nerve, FICB: fascia iliaca compartment block, SD: standard deviation, CI: confidence interval.

Postoperative quadriceps muscle strength grades at 6 hours were significantly higher in patients receiving the combined PENG and LFCN block compared with FICB (MMT MD 1.10; 95% CI 0.58 to 1.62; P < 0.001; I² = 85.5%; Fig. 4A). This preservation of motor function was sustained at 24 hours (MMT MD 0.89; 95% CI 0.20 to 1.57; P = 0.012; I² = 93.2%; Fig. 4B).

Fig. 4.

Forest plots of quadriceps muscle strength grades at (A) 6 hours and (B) 24 hours. Incidence of muscle weakness at (C) 6 hours and (D) 24 hours, and (E) time to ambulation in hours. PENG: pericapsular nerve group, LFCN: lateral femoral cutaneous nerve, SD: standard deviation, CI: confidence interval, M–H: Mantel–Haenszel.

Consistent with these findings, the incidence of quadriceps muscle weakness was significantly lower in the intervention group at 6 hours (MMT < 3 RR 0.10; 95% CI 0.02 to 0.51; P = 0.005; I² = 57.7%; Fig. 4C). At 24 hours, although the RR favored the intervention, the difference was not statistically significant (MMT < 3 RR 0.26; 95% CI 0.03 to 2.29; P = 0.225; I² = 0.0%; Fig. 4D). Furthermore, the time to ambulation was significantly shorter in patients who received the combined block (MD –3.84 hours; 95% CI –7.50 to –0.19; P = 0.039; I² = 77.9%; Fig. 4E).

For opioid consumption at 24 hours, pooled analysis of three studies showed no statistically significant difference between groups (MME MD −4.72 mg; 95% CI −12.45 to 3.01; P = 0.231; I² = 92.9%; Supplementary Fig. 1A). Likewise, no significant differences were observed in the incidence of PONV (RR 0.85; 95% CI 0.51 to 1.41; P = 0.521; I² = 0%; Supplementary Fig. 1B).

5. Sensitivity and subgroup analyses

Leave-one-out sensitivity analyses for postoperative pain and adverse events did not materially alter the pooled results. However, the exclusion of the study by Vetrone et al. [26] attenuated the effect estimate for opioid consumption, yielding a near-zero difference between groups (Supplementary Fig. 2). Overall, sensitivity analyses supported the robustness of the primary findings (Supplementary Table 2).

In analyses restricted to studies at low risk of bias, the combined block was associated with greater reductions in pain at both 6 and 24 hours, exceeding a 1-point difference on the NRS. The analgesic effect was more pronounced in patients receiving spinal anesthesia and was not sustained in those undergoing general anesthesia. Compared with FICB, a significant benefit was observed when the infrainguinal approach was used (NRS MD −1.88; 95% CI −2.39 to −1.38; P < 0.001), but not when compared with suprainguinal FICB (NRS MD −0.34; 95% CI −0.69 to 0.00; P = 0.052). The analgesic benefit was consistent in patients with hip fractures but was smaller and not sustained in THA. Both 20-mL and 25- to 35-mL PENG block volumes were associated with effective analgesia.

6. Publication bias

Visual inspection of funnel plots revealed no evidence of asymmetry for the assessed outcomes (Supplementary Fig. 3). Egger’s test confirmed the absence of publication bias for resting pain at 6 and 24 hours (P = 0.738; P = 0.698), dynamic pain at 6 and 24 hours (P = 0.515; P = 0.343), quadriceps muscle strength scores at 6 and 24 hours (P = 0.899; P = 0.955), time to ambulation (P = 0.955), PONV (P = 0.270), and opioid consumption at 24 hours (P = 0.528). However, the test could not be calculated for the incidence of muscle weakness at 6 and 24 hours due to the small number of studies (< 3).

7. Trial sequential analysis

The TSA results are displayed in Supplementary Fig. 4. For resting pain at 6 hours, TSA showed that although the RIS was not reached, the cumulative Z-curve crossed the trial sequential monitoring boundary, indicating suggestive but insufficient evidence of benefit favoring the combined PENG and LFCN block. For resting pain at 24 hours, dynamic pain at 6 hours, PONV, time to ambulation, quadriceps muscle strength at 24 hours, incidence of quadriceps muscle weakness, and opioid consumption at 24 hours, the RIS was not achieved, and monitoring boundaries were not crossed, rendering the evidence inconclusive. For quadriceps muscle strength and the incidence of muscle weakness at 6 hours, the RIS was reached, and the monitoring boundary was crossed, indicating a benefit in favor of the PENG plus LFCN combination. For dynamic pain at 24 hours, the RIS was reached, and the cumulative Z-curve remained within the futility zone, confirming the absence of a statistically significant difference between the groups.

8. Certainty of evidence

According to the GRADE assessment, the certainty of evidence was rated as very low to high (Table 2). The certainty for resting postoperative pain at both 6 hours and 24 hours (six RCTs; n = 442) was downgraded to low due to risk of bias, substantial heterogeneity, and imprecision related to limited sample size. Total opioid consumption at 24 hours (three RCTs; n = 212) was rated as very low certainty because of considerable heterogeneity, methodological differences across studies, and CIs crossing the line of no effect. Evidence for PONV (five RCTs; n = 382) was rated as very low certainty owing to risk of bias and imprecise effect estimates. Regarding functional outcomes, the evidence for quadriceps muscle strength at 6 hours was rated as high certainty, supported by a strong magnitude of effect. Conversely, the certainty for quadriceps strength at 24 hours, incidence of muscle weakness, and time to ambulation ranged from moderate to very low, primarily downgraded due to inconsistency driven by heterogeneity and imprecision from insufficient sample sizes.

Table 2.

Grading of Recommendations Assessment, Development and Evaluation (GRADE)

Outcome	Number of participants	GRADE	I2 (%)	Absolute effect (95% CI)	Comment
Resting postoperative pain score at 6 hours	442 (6 RCTs)	⨁⨁◯◯ Lowa,b,c	66.9	MD −0.72 points (−1.28 to −0.16)	Risk of bias: Seriousa; Inconsistency: Seriousb; Indirectness: Not serious; Imprecision: Very seriousc; Other considerations: Strong association.
Resting postoperative pain score at 24 hours	442 (6 RCTs)	⨁⨁◯◯ Lowa,c,d	84.8	MD −0.91 points (−1.59 to −0.23)	Risk of bias: Seriousa; Inconsistency: Seriousd; Indirectness: Not serious; Imprecision: Very seriousc; Other considerations: Strong association.
Total opioid consumption in oral morphine equivalents	212 (3 RCTs)	⨁◯◯◯ Very lowe,f,g	92.9	MD −4.72 mg (−12.45 to 3.01)	Risk of bias: Seriouse; Inconsistency: Seriousf; Indirectness: Not serious; Imprecision: Very seriousg; Other considerations: None.
Incidence of postoperative nausea and vomiting	382 (5 RCTs)	⨁◯◯◯ Very lowg,h	0.0	RR 0.85 (0.51 to 1.41)	Risk of bias: Serioush; Inconsistency: Not serious; Indirectness: Not serious; Imprecision: Very seriousg; Other considerations: None.
Dynamic postoperative pain score at 6 hours	382 (5 RCTs)	⨁◯◯◯ Very lowg,h,i	80.6	MD –0.73 (–1.49 to 0.03)	Risk of bias: Serioush; Inconsistency: Seriousi; Indirectness: Not serious; Imprecision: Very seriousg; Other considerations: None.
Dynamic postoperative pain score at 24 hours	382 (5 RCTs)	⨁⨁◯◯ Lowh,j	28.1	MD –0.06 points (–0.24 to 0.13)	Risk of bias: Serioush; Inconsistency: Not seriousi; Indirectness: Not serious; Imprecision: Very seriousj; Other considerations: None.
Quadriceps muscle strength scores at 6 hours	288 (4 RCTs)	⨁⨁⨁⨁ Highk	66.9	MD 1.10 points (0.58 to 1.62)	Risk of bias: Not serious; Inconsistency: Seriousk; Indirectness: Not serious; Imprecision: Not serious; Other considerations: Strong association.
Quadriceps muscle strength scores at 24 hours	288 (4 RCTs)	⨁⨁◯◯ Lowc,l	93.2	MD 0.89 points (0.20 to 1.57)	Risk of bias: Not serious; Inconsistency: Seriousl; Indirectness: Not serious; Imprecision: Seriousc; Other considerations: None.
Incidence of muscle weakness at 6 hours	154 (2 RCTs)	⨁⨁◯◯ Lowm,n	57.7	RR 0.10 (0.02 to 0.51)	Risk of bias: Seriousm; Inconsistency: Seriousn; Indirectness: Not serious; Imprecision: Not serious; Other considerations: None.
Incidence of muscle weakness at 24 hours	154 (2 RCTs)	⨁◯◯◯ Very lowg,m	0.0	RR 0.26 (0.03 to 2.29)	Risk of bias: Seriousm; Inconsistency: Not serious; Indirectness: Not serious; Imprecision: Very seriousg; Other considerations: None.
Time to ambulation	228 (3 RCTs)	⨁⨁⨁◯ Moderatec,o	77.9	MD –3.84 hours (–7.50 to -0.19)	Risk of bias: Not serious; Inconsistency: Seriouso; Indirectness: Not serious; Imprecision: Seriousc; Other considerations: Strong association.

CI: confidence interval, RCTs: randomized controlled trials, MD: mean difference, RR: risk ratios.

^aRisk of bias: Four studies with “some concerns” (missing data, outcome measurement, deviations). ^bInconsistency: High heterogeneity (I² ≈ 67%) due to clinical/methodological diversity (surgery type, comparator S-FICB vs. FICB, dose/adjuvants, timing). ^cImprecision: Insufficient sample size. ^dInconsistency: High heterogeneity (I² ≈ 85%) due to clinical/methodological diversity. ^eRisk of bias: Concerns regarding outcome measurement in two of three studies. ^fInconsistency: Very high heterogeneity (I² = 92.9%), mainly driven by comparator (high-volume S-FICB vs. classic FICB) and analgesic protocols. ^gImprecision: CI crosses the null value; insufficient sample size. ^hRisk of bias: “Some concerns” in three of five studies (missing data, deviations, measurement). ⁱInconsistency: High heterogeneity (I² ≈ 80%) due to clinical/methodological diversity. ^jImprecision: CI crosses the null value. ^kInconsistency: High heterogeneity (I² = 85.5%) due to clinical/methodological diversity. ^lInconsistency: High heterogeneity (I² = 93.3%) due to clinical/methodological diversity. ^mRisk of bias: “Some concerns” in both studies (deviations, missing data, measurement). ⁿInconsistency: Considerable heterogeneity (I² = 57.7%) due to clinical/methodological diversity. ^oInconsistency: High heterogeneity (I² = 77.9%) due to clinical/methodological diversity.

DISCUSSION

In this systematic review and meta-analysis, the PENG plus LFCN combination reduced resting pain within the first 24 hours and demonstrated superior motor preservation, specifically greater quadriceps strength and earlier ambulation, when compared to the FICB.

The literature suggests that the PENG plus LFCN combination may provide more anatomically targeted analgesia by selectively anesthetizing the articular branches of the anterior hip capsule while largely sparing motor fibers [32]. In contrast, the FICB produces a broader anesthetic spread and is frequently associated with quadriceps weakness, which can delay early mobilization [33,34]. This anatomical rationale supports the integration of the PENG plus LFCN combination into multimodal analgesic protocols, with potential applicability within Enhanced Recovery After Surgery pathways, as endorsed by recent PROSPECT recommendations [35,36].

Clinically, the combined technique facilitates early mobilization and preserves muscle strength, supported by both anatomical rationale and trial data [13,14,26,28–30]. By preserving motor function during the initial 24 to 48 postoperative hours, this approach promotes early ambulation, potentially reducing thromboembolic risk and accelerating functional recovery [37]. Unlike extensive regional techniques associated with quadriceps weakness, the PENG plus LFCN combination delivers joint-specific analgesia with minimal neuromuscular impairment [38]. This motor-sparing profile demonstrated in this meta-analysis is ideal for accelerated rehabilitation protocols [38].

Regarding analgesic efficacy, the authors’ meta-analysis showed that the combined block demonstrated lower pain scores, with the certainty of evidence being low. Although statistically significant, overall resting pain reductions at 6 and 24 hours did not reach the minimum clinically important difference of 1 point [39]. However, clinical superiority was evident against traditional infrainguinal FICB, but not against suprainguinal FICB. Thus, particularly in comparison to suprainguinal FICB, the primary advantage of the combined block is motor preservation rather than superior analgesic potency.

Regarding dynamic pain, the non-significant reduction at 6 hours remains inconclusive, as TSA indicated the RIS was not reached. At 24 hours, the lack of difference likely reflects the pharmacokinetic limits of single-injection blocks, which typically provide insufficient coverage for movement-evoked pain beyond 18–24 hours [14].

The included studies also highlighted important methodological and clinical considerations. Anatomical variability of the LFCN limits cutaneous analgesia in anterior approaches, whereas its contribution is minimal in posterolateral incisions [14,28]. Regarding motor function, despite the PENG block’s sparing profile, transient quadriceps weakness may occur due to high volumes causing femoral spread or during early assessment [13,26]. Furthermore, heterogeneity in anesthetic regimens may have influenced the outcomes, as higher FICB volumes increase motor blockade, while concentration variations affect analgesic efficacy [28,29].

The findings of this review partially contrast with recent meta-analyses comparing the PENG block alone with the FICB, which reported lower 24-hour opioid consumption with PENG (reductions of approximately 7–9 mg in MME) but no consistent differences in pain scores at 6 or 24 hours [40,41]. The absence of a clear opioid-sparing effect in the present analysis may be attributable to the limited number of studies assessing this outcome, comparisons with suprainguinal FICB or the inclusion of heterogeneous surgical populations.

Notably, prior network meta-analyses have not directly compared the combined PENG plus LFCN block with FICB. Hayashi et al. [42] did not evaluate combined techniques, Lee et al. [15] included only a single study addressing this comparison, and Hussain et al. [43] did not incorporate this combination. Accordingly, the present study represents the first systematic review and meta-analysis specifically designed to quantitatively compare PENG plus LFCN with FICB across multiple RCTs.

Sensitivity analyses indicated that the magnitude of benefit associated with the combined block depended on the comparator technique. The PENG plus LFCN combination demonstrated greater analgesic efficacy when compared with infrainguinal FICB but not when compared with suprainguinal FICB. These findings are consistent with a meta-analysis showing the superiority of suprainguinal FICB over conventional infrainguinal FICB and placebo in THA, with significant reductions in opioid consumption at 24 and 48 hours [44]. Collectively, these results suggest that suprainguinal FICB achieves analgesic efficacy comparable to that of the PENG plus LFCN combination, whereas infrainguinal FICB is less effective.

The sensitivity analysis also suggests that the intraoperative anesthetic regimen influences the analgesic benefit of the combined block, since it was more pronounced and statistically significant in patients receiving spinal anesthesia (with intrathecal opioids), but not in the general anesthesia subgroup. The reason behind it is unclear, but it indicates that the main benefit of the combined blocks is related to advantages regarding functional recovery of muscle strength. However, it is important to note that TSA indicated that the RIS was not reached for some outcomes, limiting the strength of the evidence and underscoring the need for further adequately powered trials.

From a practical standpoint, the requirement for two distinct ultrasound-guided injections in the combined PENG and LFCN technique could translate into longer procedural times compared to the single-injection FICB, which would potentially have a negative impact in the operation room logistic and general workflow. However, Shalaby et al. [13], one of the included studies evaluating this metric, reported no statistically significant difference in block performance times between the groups. Consequently, feasibility in routine practice likely depends on the anesthesiologist’s proficiency and familiarity with the specific sonoanatomy. Nonetheless, future studies on this matter should include this evaluation as part of the analyzed outcomes.

Given the low certainty of the evidence and the considerable heterogeneity among studies, the use of this combined technique should be individualized. Further well-designed, adequately powered randomized trials are required to better establish its clinical impact and objectively evaluate its practical feasibility for routine implementation.

SUPPLEMENTARY MATERIALS

Supplementary materials can be found via https://doi.org/10.3344/kjp.26030.