Proximal femur surgeries are frequently associated with significant perioperative pain, particularly in patients with femoral fractures, in whom movement and positioning for neuraxial anaesthesia may be extremely uncomfortable. Effective preoperative analgesia is therefore important not only for patient comfort but also for facilitating appropriate positioning for spinal anaesthesia and improving the overall perioperative experience [1,2]. Inadequate pain control may contribute to delayed mobilisation, increased physiological stress, and postoperative morbidity [3].

Regional anaesthesia techniques have traditionally included femoral nerve block and fascia iliaca compartment block for providing analgesia in patients undergoing proximal femur and hip surgeries. However, these techniques may provide incomplete analgesia because the sensory innervation of the hip joint is complex, and femoral nerve blockade may also produce quadriceps motor weakness [1,4,5]. The pericapsular nerve group (PENG) block was introduced as a relatively novel ultrasound-guided regional anaesthetic technique targeting the articular branches of the femoral, obturator, and accessory obturator nerves supplying the anterior hip capsule [2]. Its motor-sparing characteristics have generated considerable interest in patients undergoing hip and proximal femur surgery.

The PENG block has been reported to provide effective analgesia while potentially preserving motor function, making it attractive for both perioperative pain management and facilitating early mobilisation [2,4]. Subsequent clinical studies have demonstrated its usefulness in hip fracture and arthroplasty patients, although the analgesic efficacy of the technique may depend on the local anaesthetic used, volume administered, and addition of appropriate adjuvants [6-8].

Ropivacaine is commonly used for peripheral nerve blocks because of its long duration of action and favourable safety profile. However, the duration of analgesia produced by local anaesthetic alone may be insufficient for prolonged postoperative pain control. Consequently, various adjuvant drugs have been investigated to enhance the duration and quality of regional analgesia. Dexamethasone has been widely studied as a perineural adjuvant and may prolong the duration of analgesia when combined with local anaesthetics [9]. Fentanyl, an opioid analgesic, has also been used as an adjuvant to regional anaesthetic techniques with the objective of improving analgesic efficacy [10].

In patients undergoing proximal femur surgery, an effective regional block has an additional advantage because it may reduce pain during the transition from the supine to sitting position required for spinal anaesthesia. Previous studies have demonstrated the usefulness of regional blocks for facilitating positioning of patients with femoral fractures for neuraxial anaesthesia [4,5]. Therefore, comparison of different adjuvants in PENG block is clinically relevant, particularly when both immediate positioning comfort and postoperative analgesia are considered.

The present study was undertaken to compare 0.2% ropivacaine combined with dexamethasone versus 0.2% ropivacaine combined with fentanyl in ultrasound-guided PENG block for patients undergoing proximal femur surgery. The primary objective was to compare the analgesic efficacy of the two adjuvant combinations, while the secondary objectives were to evaluate patient comfort during positioning for spinal anaesthesia and to assess haemodynamic changes and potential adverse effects.

This prospective, randomized, double-blind comparative study was conducted after obtaining approval from the Institutional Ethics Committee and appropriate trial registration. A total of 60 patients aged 18–65 years, belonging to ASA physical status I or II, and scheduled for elective proximal femur surgery under subarachnoid block were included after obtaining written informed consent. Patients with central or peripheral neuropathies, bleeding disorders, allergy to any study drug, infection at the proposed block site, psychiatric disorders affecting pain assessment, BMI >30 kg/m², or pregnancy were excluded. The patients were randomly allocated into two groups of 30 patients each. Group PD received an ultrasound-guided PENG block using 15 mL of 0.2% ropivacaine with dexamethasone 4 mg, whereas Group PF received 15 mL of 0.2% ropivacaine with fentanyl 50 µg. Preoperative assessment included demographic characteristics, clinical examination, ASA physical status, and routine investigations. Patients were familiarized with the Visual Analog Scale (VAS), ranging from 0 for no pain to 10 for the worst imaginable pain. The PENG block was performed under strict aseptic precautions using a low-frequency curvilinear ultrasound probe. The probe was positioned over the anterior inferior iliac spine and rotated approximately 45° counter-clockwise to identify the superior pubic ramus. The ilio-pubic eminence, iliopsoas muscle, psoas tendon, and femoral neurovascular structures were identified. A 22-gauge needle was advanced using an in-plane technique, with the needle tip positioned between the psoas tendon anteriorly and the pubic ramus posteriorly. After negative aspiration, the assigned study solution was injected into the identified fascial plane. Pain was assessed before the block and again 10 minutes after administration of the PENG block. Patients were subsequently positioned for spinal anaesthesia. Comfort during positioning was evaluated using a four-point patient satisfaction scale, ranging from 0, representing unsatisfactory comfort, to 3, representing optimal comfort. Patients who failed to achieve adequate analgesia and required rescue medication for positioning were considered block failures. Subarachnoid anaesthesia was subsequently administered using a conventional midline approach at the L3–L4 interspace with a 26-gauge Quincke needle. After confirmation of intrathecal placement, 3 mL of 0.5% hyperbaric bupivacaine was administered. Heart rate, blood pressure, oxygen saturation, and ECG were monitored throughout the perioperative period. Hypotension was managed according to the study protocol, while bradycardia was treated with intravenous atropine when required. Postoperative pain was assessed using the VAS at regular intervals, initially every 30 minutes for the first 2 hours, followed by two-hourly assessments for the subsequent 8 hours and then four-hourly assessments for the next 24 hours. The duration of effective analgesia was defined as the time from administration of the PENG block to the first requirement for rescue analgesia or a VAS score greater than 3. Intravenous diclofenac 75 mg was used as the initial rescue analgesic, while intravenous tramadol 1 mg/kg was administered when additional analgesia was required. Patients were monitored throughout the postoperative period for adverse effects and other complications. The study initially enrolled 60 patients, with 30 patients allocated to each group. Quantitative variables were expressed as mean ± standard deviation, while categorical variables were expressed as frequencies and proportions. Statistical analysis was performed using appropriate comparative tests, including the unpaired t-test and chi-square test. A p value <0.05 was considered statistically significant. Postoperative assessments were performed by an anaesthesiologist who was blinded to the group allocation.

The demographic characteristics of the participants are presented in Table 1. The mean age was comparable between Group PD and Group PF (53.034±9.686 vs. 54.3±10.114 years; p=0.305). The distribution of gender was also comparable between the two groups, with 38 males and 37 females in Group PD and 40 males and 35 females in Group PF (p=0.500). Similarly, ASA status showed no statistically significant difference between the groups (p=0.495). The mean body weight was 63.567±7.704 kg in Group PD and 64.134±7.842 kg in Group PF (p=0.291). The mean duration of surgery was 142.6±9.031 minutes in Group PD and 146.4±7.295 minutes in Group PF, with the difference approaching statistical significance (p=0.050).

The comparison of VAS scores is shown in Table 2. Before administration of the PENG block, the mean VAS score was 6.567±1.223 in Group PD and 6.5±1.252 in Group PF, with no statistically significant difference between the groups (p=0.408). Ten minutes after the PENG block, the VAS score decreased substantially in both groups to 2.167±0.791 in Group PD and 2.234±0.728 in Group PF. The difference between the groups remained statistically non-significant (p=0.365).

Patient satisfaction following the block and during positioning for spinal anaesthesia is presented in Table 3. The mean satisfaction score was 2.1±0.759 in Group PD and 2.0±0.743 in Group PF. Although the satisfaction score was marginally higher in Group PD, the difference was not statistically significant (p=0.328).

Table 1. Comparison of Demographic Factors Between the Study Groups

Table 2. Comparison of VAS Scores Between the Study Groups

Table 3. Comparison of Patient Satisfaction Scores Between the Study Groups

The present comparative study evaluated the analgesic efficacy of 0.2% ropivacaine combined with dexamethasone versus fentanyl when used for PENG block in patients undergoing proximal femur surgery. The study also assessed patient comfort during positioning for spinal anaesthesia. The findings demonstrated a substantial reduction in pain following PENG block in both groups. However, the difference in postoperative VAS scores between the dexamethasone and fentanyl groups was not statistically significant, suggesting comparable short-term analgesic efficacy of the two adjuvant combinations. The PENG block was introduced as an ultrasound-guided technique targeting the articular branches supplying the anterior hip capsule and has subsequently gained considerable attention in hip and proximal femur surgery. Girón-Arango et al. initially described the technique in patients with hip fracture and demonstrated its potential to provide analgesia while avoiding the extensive motor blockade associated with some conventional approaches [2]. Subsequent clinical studies and systematic reviews have supported the role of PENG block as an effective regional analgesic technique for hip surgery [11,12]. In the present study, the pre-block VAS scores were comparable between Group PD and Group PF (6.567±1.223 and 6.5±1.252, respectively; p=0.408), indicating similar baseline pain intensity. Ten minutes after the PENG block, VAS scores decreased markedly in both groups to 2.167±0.791 in Group PD and 2.234±0.728 in Group PF. Although the reduction was numerically greater in the dexamethasone group, the difference between the groups was not statistically significant (p=0.365). These findings suggest that both adjuvant combinations provided effective early analgesia after PENG block. The reduction in pain following PENG block is clinically relevant in patients undergoing proximal femur surgery because movement of the affected limb and positioning for neuraxial anaesthesia can be particularly painful. Previous research evaluating regional analgesic techniques before spinal anaesthesia has demonstrated improved pain control and positioning quality compared with systemic opioid administration alone [11]. In a randomized trial comparing fascia iliaca block with intravenous fentanyl, regional blockade produced superior analgesia and improved positioning for spinal anaesthesia in patients undergoing femur fracture surgery [12]. These observations support the importance of effective regional analgesia before positioning, although the present study directly compared two adjuvants within the PENG block rather than comparing a block with systemic fentanyl. Dexamethasone has been widely investigated as an adjuvant to local anaesthetics in peripheral nerve blocks because of its potential to prolong analgesia. Its proposed mechanisms include modulation of inflammatory responses and effects on neural transmission, although the exact mechanism underlying prolongation of peripheral nerve block remains incompletely established [13]. The use of dexamethasone with ropivacaine in the present study therefore represents a strategy intended to enhance the duration and quality of regional analgesia. Fentanyl is an opioid analgesic that has also been used as an adjuvant in regional anaesthetic techniques. The analgesic effects of fentanyl are mediated predominantly through opioid receptors, and its use in regional techniques has been explored with the objective of improving analgesia while potentially reducing the requirement for systemic analgesics [14]. In the present study, the comparable VAS scores between the two groups suggest that fentanyl provided an analgesic effect similar to dexamethasone during the early post-block period. Patient comfort during positioning for spinal anaesthesia is another clinically important outcome in patients undergoing proximal femur surgery. The mean satisfaction score was 2.1±0.759 in Group PD compared with 2.0±0.743 in Group PF, with no statistically significant difference (p=0.328). Although the dexamethasone group demonstrated a marginally higher satisfaction score, both groups achieved broadly comparable patient comfort. Previous evidence indicates that regional analgesia can substantially improve the ability of patients with femoral fractures to tolerate positioning for neuraxial anaesthesia [12]. The present findings are also consistent with the broader literature suggesting that PENG block can provide effective analgesia for hip and proximal femur procedures. Meta-analyses and systematic reviews have reported reductions in opioid requirements and favourable postoperative analgesic outcomes following PENG block, although variations in local anaesthetic concentration, volume, adjuvant selection, surgical procedure, and assessment methods can influence observed outcomes [11,15]. Therefore, the absence of a significant difference between dexamethasone and fentanyl in the present study does not necessarily indicate equivalence in all aspects of postoperative analgesia. The demographic characteristics of the two groups were broadly comparable. Mean age, weight, gender distribution, and ASA status did not demonstrate statistically significant differences. This comparability reduces the likelihood that differences in baseline patient characteristics substantially influenced the observed pain outcomes. The duration of surgery was slightly longer in Group PF than Group PD, although the difference was close to the conventional level of statistical significance (p=0.050). This variable may potentially influence postoperative pain and should therefore be considered when interpreting the findings. The study has certain limitations. The available results provide VAS measurements at baseline and 10 minutes after the block and a patient satisfaction score, but detailed long-term postoperative VAS measurements and analgesic consumption are not included in the supplied tables. Therefore, conclusions regarding prolonged analgesic duration should not be made beyond the available observations. Further studies with larger sample sizes, standardized surgical procedures, serial postoperative pain assessments, rescue analgesic consumption, and longer follow-up would provide more comprehensive evidence regarding the comparative duration of dexamethasone and fentanyl as PENG block adjuvants.

Both 0.2% ropivacaine with dexamethasone and 0.2% ropivacaine with fentanyl provided effective analgesia when used for PENG block in patients undergoing proximal femur surgery. VAS scores decreased substantially following the block in both groups, with no statistically significant difference between the groups at 10 minutes. Patient satisfaction during positioning for spinal anaesthesia was also comparable. Within the limitations of the available data, both combinations appear to provide effective short-term analgesia and facilitate patient positioning for spinal anaesthesia.

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