INTRODUCTION Hip surgeries are commonly performed for conditions such as femoral neck fractures, intertrochanteric fractures, osteoarthritis, and avascular necrosis, particularly in the elderly. These procedures are associated with significant postoperative pain, which can delay mobilization, prolong hospital stay, increase complications, and impair recovery. Effective postoperative analgesia is therefore a key component of enhanced recovery after surgery (ERAS) protocols and modern perioperative care.[1–5]. Although opioids and neuraxial techniques provide effective pain relief, their use is often limited by adverse effects such as nausea, vomiting, respiratory depression, hypotension, urinary retention, motor blockade, and delayed mobilization. Consequently, peripheral nerve blocks have become an important part of multimodal analgesia for hip surgeries.[6–8]. Lumbar plexus block (LPB), also known as the psoas compartment block, provides effective analgesia by blocking the femoral, obturator, and lateral femoral cutaneous nerves, which supply most of the hip joint. Compared with isolated femoral nerve block, LPB offers more comprehensive postoperative pain relief.[9–13]. Several techniques for LPB have been described. Capdevila's posterior approach, developed from anatomical and CT-based studies, was designed to improve block reliability and reduce complications such as epidural spread. In contrast, Winnie's anterior approach is technically simpler and less invasive but may provide less consistent blockade of the obturator and lateral femoral cutaneous nerves, potentially limiting its analgesic effectiveness in hip surgery.[14–27]. Despite the widespread use of both techniques, direct comparative evidence regarding their analgesic efficacy and safety remains limited. Therefore, this prospective comparative study was undertaken to evaluate Capdevila's posterior approach and Winnie's anterior approach for lumbar plexus block in patients undergoing hip surgeries, with respect to postoperative pain, duration of analgesia, rescue analgesic requirement, and complications.

STUDY DESIGN: This was a prospective comparative study. STUDY SETTINGS: The study was conducted at a tertiary care hospital. DURATION OF STUDY: The study was conducted over 18 months. IEC APPROVAL Ethical clearance for the study was obtained from the Institutional Ethics Committee(IEC) of the institution prior to commencement of the study (IEC Approval No:MPGI/IEC/outward no./77/2024 , Dated 27/06/2024) Study conducted_in_strict_accordance with the ICMR National Ethical Guidelines for Biomedical and Health Research Involving Human Participants (2017) and the Declaration of Helsinki (2013 revision) and institutional guidelines. SAMPLE SIZE CALCULATION The sample size was calculated using data from a previous study conducted by Aytolign HA et al. A sample size of subjects 70 (35 in each group), is sufficient to detect a difference between the two groups, using a two-tailed Z-test of difference between means with 80% power and a 5% level of significance. Considering an attrition rate of 10% the sample size required is 78 (39 per group). SAMPLING METHOD Consecutive sampling was used to select patients for the study and patients are divided into two groups. INCLUSION CRITERIA • Patients aged 18 years and above • Patients scheduled for elective hip surgeries • Participants who provided informed consent • Patients with ASA grade 1 or EXCLUSION CRITERIA • Allergy to local anesthetic drugs • Infection at the administration site • Pre-existing neurological disorders • Coagulopathies PROCEDURE • Written Informed consent was obtained from all patients. • Patients were allocated into two groups. • Patients were taken to the operation theatre. • Standard ASA monitors were attached, such as pulseoximeter ,NIBP ,ECG and EtCo2 . • vitals were recorded: HR ,SBP ,DBP ,MAP ,Spo2 ,EtCo2 and RR. • Spinal anesthesia was administered using a 25G needle with Inj. Bupivacaine (0.5%) in an appropriate dose. • Intraoperative monitoring of HR ,SBP ,DBP ,MAP ,Spo2 ,EtCo2 and RR. • was conducted. • After surgery, lumbar plexus block was administered inside the ot: • Drug solution used in both approaches: Inj. Bupivacaine (0.5%) — 10 Ml Inj. Lignocaine + adrenaline (2%) — 10 mL Normal Saline — 20 mL T otal volume = 40 ML Group A: Lumbar Plexus Block: Capdevila's Approach The lumbar plexus block was performed using Capdevila's posterior psoas compartment approach under peripheral nerve stimulator guidance as follows: • The patient was positioned in the lateral decubitus position with the operative side uppermost and the hip and knee flexed to approximately 90°. • Standard ASA monitors (ECG, non-invasive blood pressure, and pulse oximetry) were applied, and baseline vital signs were recorded. • Under strict aseptic precautions, the lumbar region was prepared with povidone-iodine followed by an alcohol-based antiseptic solution, allowed to dry, and draped with sterile sheets. • The block was performed using sterile gloves, an insulated stimulating needle, and sterile equipment. • The L4 spinous process, posterior superior iliac spine (PSIS), and vertebral midline were identified as anatomical landmarks. • A horizontal line was drawn from the L4 spinous process and a vertical line through the PSIS. The needle insertion point was marked at the junction of the lateral one-third anmedial two-thirds of the line joining these landmarks. • A peripheral nerve stimulator was attached to an insulated needle and set at 1–1.5 mA, 2 Hz, and 0.1 ms. • After local infiltration, the needle was inserted perpendicular to the skin at the marked point and advanced until the L4 transverse process was contacted. • The needle was then withdrawn slightly, redirected caudally beyond the transverse process, and advanced until quadriceps contraction with patellar movement (patellar snap) was elicited. • The stimulating current was gradually reduced, and the final needle position was confirmed when the motor response persisted at 0.3–0.5 mA. • Following negative aspiration, 40 mL of the study drug was injected incrementally with repeated aspiration between aliquots. • Successful block was confirmed by sensory loss over the anterior and medial thigh, weakness of knee extension and hip flexion, and adequate postoperative analgesia. • After local infiltration, the insulated needle was inserted at approximately 45° to the skin and advanced cephalad under peripheral nerve stimulator guidance. • The needle was advanced until quadriceps contraction with patellar movement (patellar snap) was elicited. The stimulating current was gradually reduced, and the final needle position was confirmed when the response persisted at 0.3–0.5 mA and disappeared below 0.2 mA. • Firm distal pressure was applied 2–4 cm below the insertion site to facilitate cephalad spread of the local anaesthetic. • After negative aspiration, 40 mL of the study drug was injected incrementally with repeated aspiration between aliquots. • The needle was removed, distal pressure was maintained, and gentle cephalad massage was performed to promote proximal spread of the local anaesthetic. • Successful block was confirmed by sensory loss over the anterior and medial thigh, weakness of knee extension and hip flexion, and adequate postoperative analgesia. Outcome Measures: • Primary Outcome: VAS score at time interval- 0,2,4,6,8,12 hrs. • Secondary Outcomes: Duration of analgesia, incidence of complications (nerve injury, vascular puncture, local anesthetic toxicity), and requirement for rescue analgesia • Data Collection: • Data were collected prospectively using standardized case report forms. Pain scores were recorded at predefined postoperative time points, and any complications were documented. STATISTICAL ANALYSIS Data were stored in Microsoft Excel and analyzed using IBM SPSS Statistics version 28. Data were presented in tables and graphs. Frequency, percentage, and descriptive statistics were used to summarize data. The Shapiro-Wilk test was used to examine data normality. Differences between continuous normally distributed variables were analyzed using the t-test, and non-normally distributed variables were analyzed using the Mann-Whitney U test. The chi-square test or Fisher’s exact test was used to examine associations between nominal/ordinal variables. Repeated measures ANOVA and post hoc analysis were used to detect mean differences over time. A p-value of <0.05 was considered statistically significant.

In this prospective comparative study a total 78 patients undergoing hip surgeries were enrolled and allocated into two groups of 39 patients each. Lumbar plexus block by Capdevila’s approach given to the patients in Group C and Winnie’s anterior approach given to the patients in Group W. Table 1: DEMOGRAPHIC PROFILE OF PATIENTS. Table Variable Group C mean±SD/n(%) Group W mean±SD/n(%) P value Inference Age distribution Age (years) 60.00 ± 8.77 59.08 ± 8.41 0.636 Not significant SEX MALE 22 (56.4%) 20 (51.3%) 0.821 Not significant FEMALE 17 (43.6%) 19 (48.7%) Weight Comparison Weight (kg) 63.80 ± 5.17 63.96 ± 8.27 0.915 Not significant ASA GRADING ASA I 14 (35.9%) 13 (33.3%) 1.000 Not significant ASA II 25 (64.1%) 26 (66.7%) Duration of surgery Duration of surgery (min) 90.79 ± 11.14 93.51 ± 13.14 0.328 Not significant Both groups are comparable with respect to age, gender, weight, ASA grading and duration of surgery. TABLE 2: VAS score comparison Time Group C mean ± SD Group W mean ± SD p-value Inference 0 h 0.00 ± 0.00 0.00 ± 0.00 1.000 Not significant 2 h 0.46 ± 0.51 1.00 ± 0.65 0.000086 Significant 4 h 1.64 ± 0.49 2.74 ± 0.72 0.000001 Significant 6 h 2.74 ± 0.79 3.72 ± 0.72 0.000001 Significant 8 h 3.05 ± 0.56 4.05 ± 0.60 0.000001 Significant 12 h 3.85 ± 0.74 4.79 ± 0.80 0.000001 Significant The VAS scores were identical in both groups immediately after surgery (0 h), with no statistically significant difference (p = 1.000). From 2 hours onwards, Group C consistently demonstrated significantly lower VAS scores than Group W at all postoperative time points. At 2, 4, 6, 8, and 12 hours, the differences were highly significant. (p < 0.001) . The VAS scores were consistently and significantly lower in Group C compared to Group W at all postoperative time from 2 hours onwards (p< 0.001 for all comparisons) TABL 3: Outcome comparison Outcome Group C Group W p-value Inference Onset of action (min) 12.85 ± 1.79 15.19 ± 1.61 0.000000043 Significant Duration of analgesia (min) 760.38 ± 64.59 585.44 ± 64.55 0.000001 Significant Time to first rescue analgesia (min) 722.79 ± 57.84 574.38 ± 63.12 0.000001 Significant Total rescue analgesic consumption in 24 h (mg) 115.38 ± 37.88 176.92 ± 36.45 0.000001 Significant The onset of action occurred earlier in the Capdevila group than in the Winnie group. Patients who received the Capdevila approach developed motor block in 12.85 ± 1.79 minutes, while those in the Winnie approach group required 15.19 ± 1.61 minutes. Statistical analysis demonstrated a highly significant difference between the groups (p < 0.001). These findings suggest that the Capdevila approach provides a more rapid onset of motor blockade compared with Winnie’s anterior approach. The duration of post operative analgesia was significantly prolonged in Group C (760.38± 64.59 minutes) compared to Group W (585.44± 64.55 minutes), with a highly significant p-value value <0.001. The time to first rescue analgesic requirement was significantly delayed in Group C (722.79± 57.84 minutes compared to Group W (574.38 ± 63.12 minutes) and this difference was statistically significant (p<0.001). The total rescue analgesic consumption (Inj.Tramadol) in the first 24 postoperative hours was significantly lower in Group C (115.38± 37.88mg) compared to Group W (176.92± 36.45mg).This difference was found to be statistically significant (p<0.001) . TABLE NO. 4: COMPLICATIONS Complication Group C (n=39) Group W (n=39) P value Nausea/Vomiting 2 (5.1%) 3 (7.7%) 0.347 Transient Paraesthesia 1 (2.6%) 3 (7.7%) Vascular Puncture 1 (2.6%) 2 (5.1%) Total Complications 4 (10.3%) 8 (20.5%) No Complication 35 (89.7%) 31 (79.5%) The difference in complication rates between the two groups was not statistically significant (p=0.347).

The present prospective comparative study evaluated the effectiveness of Capdevila's posterior approach and Winnie's anterior approach of lumbar plexus block for postoperative analgesia in patients undergoing hip surgeries. Both groups were comparable with respect to demographic characteristics, ASA physical status, type of surgery, and duration of surgery, indicating that the observed differences in postoperative outcomes were attributable to the block technique rather than baseline patient characteristics. The results demonstrated that patients receiving Capdevila's posterior approach experienced a significantly faster onset of motor blockade than those receiving Winnie's anterior approach. The mean onset time was 12.85 ± 1.79 minutes in the Capdevila group compared with 15.19 ± 1.61 minutes in the Winnie group (p < 0.001). These findings are in agreement with previous studies by Capdevila et al., Becchi et al., and Aytolign et al., which also reported a rapid onset with posterior lumbar plexus block. The earlier onset observed with the posterior approach is probably related to the deposition of local anaesthetic within the psoas compartment, allowing direct spread around the lumbar plexus and its branches. Another important finding of the present study was the significantly prolonged duration of postoperative analgesia in the Capdevila group (760.38 ± 64.59 minutes) compared with the Winnie group (585.44 ± 64.55 minutes). Consequently, patients in the posterior approach group required their first rescue analgesic significantly later and consumed less rescue analgesic during the first 24 postoperative hours. These findings are consistent with those reported by Srivastava et al., Mannion et al., Atim et al., and Biboulet et al., all of whom demonstrated superior analgesic efficacy with posterior lumbar plexus block techniques. The prolonged analgesia achieved with Capdevila's approach is likely due to more reliable blockade of the femoral, obturator, and lateral femoral cutaneous nerves, resulting in more comprehensive coverage of the sensory innervation of the hip joint. Postoperative pain assessment further supported these findings. Visual Analogue Scale (VAS) scores were significantly lower in the Capdevila group at all postoperative intervals from 2 hours onwards, reflecting superior pain control throughout the early postoperative period. These observations are comparable with those of Aytolign et al., Becchi et al., and Srivastava et al., who also reported lower postoperative pain scores following posterior lumbar plexus block. Effective pain control not only improves patient comfort but also facilitates early mobilisation and reduces the need for systemic analgesics, thereby minimizing opioid-related adverse effects. Both block techniques maintained satisfactory hemodynamic stability throughout the study. Although minor statistical differences in heart rate and blood pressure were observed at isolated time points, these changes were not clinically significant, and no episodes of severe hypotension or bradycardia requiring intervention occurred. Likewise, the incidence of complications was low and comparable between the two groups, with no major adverse events such as epidural spread, retroperitoneal hematoma, local anaesthetic systemic toxicity, or persistent neurological deficits. These findings suggest that both techniques are safe when performed by experienced anaesthesiologists under appropriate monitoring and aseptic precautions. Overall, the present study demonstrates that Capdevila's posterior approach provides more effective postoperative analgesia than Winnie's anterior approach in patients undergoing hip surgeries. The technique offers a faster onset of blockade, prolonged analgesia, delayed rescue analgesic requirement, lower postoperative pain scores, and reduced analgesic consumption while maintaining excellent hemodynamic stability and an acceptable safety profile. These findings support the preferential use of Capdevila's posterior approach as an effective regional anaesthesia technique for postoperative pain management in hip surgery.

Capdevila’s approach provided better postoperative pain relief when compared to Winnie’s anterior approach. Patients in the Capdevila group experienced a significantly lower postoperative VAS scores, longer duration of analgesia, delayed requirement of first rescue analgesic and reduced total analgesic consumption during the first 24 hours after surgery

1. Morrison RS, Magaziner J, McLaughlin MA, et al. The impact of postoperative pain on outcomes following hip fracture. Pain. 2003;103(3):303-311. 2. Sinatra R. Causes and consequences of inadequate management of acute pain. Pain Med. 2010;11(12):1859-1871. 3. Kehlet H, Dahl JB. Anaesthesia, surgery, and challenges in postoperative recovery. Lancet. 2003;362(9399):1921-1928. 4. Soffin EM, YaDeau JT. Enhanced recovery after surgery for primary hip and knee arthroplasty. Br J Anaesth. 2016;117(Suppl 3):iii62-iii72. 5. Wainwright TW, Gill M, McDonald DA, et al. Consensus statement for perioperative care in total hip replacement. Anaesthesia. 2020;75(11):1528-1541. 6. Chou R, Gordon DB, de Leon-Casasola OA, et al. Management of postoperative pain: Clinical practice guideline. J Pain. 2016;17(2):131-157. 7. Abdallah FW, Brull R. Isolated femoral nerve block versus lumbar plexus block. Reg Anesth Pain Med. 2011;36(6):546-563. 8. Hebl JR. The importance of peripheral nerve blocks in multimodal analgesia. Reg Anesth Pain Med. 2006;31(4):289-297. 9. Birnbaum K, Prescher A, Hessler S, Heller KD. The sensory innervation of the hip joint. Clin Orthop Relat Res. 1997;335:221-226. 10. Short AJ, Barnett JJG, Gofeld M, et al. Anatomic study of hip innervation. Reg Anesth Pain Med. 2018;43(4):424-430. 11. Capdevila X, Biboulet P, Bouregba M, et al. Continuous lumbar plexus block for postoperative analgesia. Anesth Analg. 2002;94(6):1606-1613. 12. Stevens MF, Werdehausen R, Hermanns H, et al. Lumbar plexus block for hip surgery. Anesthesiology. 2006;105(4):813-820. 13. Gray AT. Atlas of Ultrasound-Guided Regional Anesthesia. 3rd ed. Philadelphia: Elsevier; 2018. 14. Winnie AP, Ramamurthy S, Durrani Z. The inguinal paravascular technique of lumbar plexus anesthesia. Anesth Analg. 1973;52(6):989-996. 15. Parkinson SK, Mueller JB, Little WL, Bailey SL. Extent of blockade with lumbar plexus block. Anesth Analg. 1989;68(3):243-248. 16. Biboulet P, Morau D, Aubas P, et al. Postoperative analgesia using lumbar plexus block. Anesthesiology. 2004;100(6):1540-1545. 17. Aida S, Takahashi H, Shimoji K. Total spinal anesthesia following lumbar plexus block. Can J Anaesth. 1998;45(5):467-470. 18. Mannion S. Epidural spread after psoas compartment block. Eur J Anaesthesiol. 2005;22(6):473-480. 19. Weller RS, Gerancher JC, Crews JC, Wade KL. Retroperitoneal hematoma after lumbar plexus block. Anesthesiology. 2003;98(2):581-585. 20. Klein SM, Nielsen KC, Greengrass RA, et al. Complications associated with lumbar plexus block. Reg Anesth Pain Med. 2002;27(2):172-176. 21. Capdevila X, Macaire P, Dadure C, et al. Continuous psoas compartment block. Anesth Analg. 2002;94(6):1606-1613. 22. Capdevila X, Biboulet P, Rubenovitch J, et al. CT-guided anatomical evaluation of lumbar plexus block. Anesthesiology. 2005;102(3):531-537. 23. Touray ST, de Leeuw MA, Zuurmond WW, Perez RS. Lumbar plexus block techniques: A review. Anesth Analg. 2008;107(3):1079-1091. 24. Chelly JE, Casati A, Al-Samsam T, et al. Continuous lumbar plexus block in hip surgery. Br J Anaesth. 2001;87(6):859-863. 25. Winnie AP. Plexus Anesthesia: Perivascular Techniques of Brachial Plexus Block. Philadelphia: Saunders; 1994. 26. Pandin PC, Vandesteene A, d'Hollander AA. Anterior approaches to lumbar plexus blockade. Reg Anesth Pain Med. 2003;28(2):109-115. 27. Horasanli E, Pala Y, Erol A, et al. Comparison of lumbar plexus block approaches. Acta Anaesthesiol Scand. 2010;54(3):310-316.