Effectiveness of Ultrasound-Guided Serial Injection Triple Nerve Block before and after Cementless Bipolar Hemiarthroplasty in Femoral Neck Fracture

Abstract

Bipolar hemiarthroplasty (BHA) is a common treatment for femoral neck fractures, but post-surgery pain can delay recovery. This study retrospectively analyzed 87 BHA patients from 2016–2020, categorizing them into two groups: Group I (n = 42) received serial injection nerve blocks (SINB) before and after surgery, while Group II (n = 41) did not. Pain was measured using a visual analog scale at multiple time points post-surgery. The groups were also compared for hospital stay length and perioperative complications. Results indicated that Group I patients, who received SINB, had significantly lower pain scores at most time intervals post-surgery and exhibited fewer instances of postoperative nausea, vomiting, and delirium. Using ultrasound-guided SINB not only provided superior pain relief but also minimized the need for narcotics and their side effects, like nausea and delirium.

1. Introduction

Bipolar hemiarthroplasty (BHA) is a common surgical intervention used to manage the acute pain associated with femoral neck fractures. While effective, BHA is linked to significant postoperative pain that, if not well-managed, can hinder recovery, lengthen hospitalization, and increase the risk of negative outcomes such as myocardial ischemia, pulmonary dysfunction, and thromboembolism. Therefore, optimal pain management after BHA should prioritize providing potent pain relief while minimizing opioid consumption and supporting recovery. Similarly, total knee arthroplasty (TKA) can also result in significant postoperative pain, and various pain management strategies are available, such as systemic or intrathecal opioids, local infiltration analgesia, and peripheral nerve blocks (PNBs). However, the ideal pain management approach should offer robust analgesia without any unwanted consequences to minimize adverse effects [1, 2, 3].

The hip joint receives innervation from multiple nerves. Specifically, the obturator nerve and articular branches of the femoral nerve innervate the anteromedial section of the hip joint, while the lateral femoral cutaneous nerve (LFCN) innervates the anterolateral section [4]. It has been observed that patients undergoing a direct lateral approach for femur neck fracture at our institution often report postoperative pain in both the anteromedial and anterolateral regions of the hip joint [5], which can be attributed to the involvement of these nerves.

Inserting a catheter that can cover all three nerves is a challenging procedure, mainly due to the complexity of the process and the location of the nerves. The femoral nerve seems to be the most feasible option, but the success of the blocks using this technique is unpredictable [4]. Using ultrasound guidance can make the procedure easier, but the results may still be unreliable. The procedure is technically difficult, even for experienced practitioners, as the space lies beyond penetrating a needle through two fascial layers [6].

Capdevila et al. recommend using continuous psoas compartment block for total hip arthroplasty, utilizing modified Winnie’s landmark [7] to determine the distance between the lumbar plexus and L4 transverse process accurately [8]. They have found that the fascia iliaca compartment block is more effective than the 3-in-1 block. However, it is worth noting that both techniques provide sensory blockade in only 35% of cases [9]. Therefore, we opted to perform a single injection of each of the three nerves before the BHA procedure, rather than dwelling a catheter on one nerve that innervates the hip joint.

Ensuring that the effects of peripheral nerve blocks are sustained is crucial to reducing opioid use among inpatients, as even small doses (20 to 50 MME/day) may increase the risk of clinical complications and long-term opioid dependence [10, 11, 12]. However, the duration of a single injection nerve block is limited to a maximum of 12 hours [13]. To extend the effects beyond 12 hours, we developed a method of serial injection.

An experienced orthopedic surgeon performed an ultrasound-guided block of the lateral femoral cutaneous nerve, obturator nerve, and femoral nerve. The procedure took less than 10 minutes for each nerve block, and it did not significantly add to the perioperative time. Furthermore, there were no local complications, such as infection or hematoma, at the injection site.

In addition to the potential temporary weakness in the quadriceps muscle, a known side effect of femoral nerve blocks [11, 12, 13], we made a concerted effort to preserve ankle dorsiflexion and plantarflexion to mitigate the risk of deep vein thrombosis (DVT) during our study.

The purpose of this investigation is to evaluate the clinical benefits of ultrasound-guided serial injection nerve blocks (SINB) targeting the femoral, obturator, and lateral femoral cutaneous nerves in patients undergoing BHA. As these peripheral nerves innervate the proximal femur and hip joint, the study aims to assess the effectiveness of SINB in achieving optimal pain relief while minimizing opioid consumption during the first 48 hours postoperatively. Furthermore, we aim to investigate the extent to which SINB decreases the incidence of postoperative nausea and vomiting (PONV) and delirium, thereby promoting enhanced rehabilitation.

2. Materials and methods

2.1 Trial design and study settings

A direct lateral approach under spinal anesthesia was utilized by a single orthopedic surgeon to perform all BHA procedures in our study. Our study population consisted of 83 patients who underwent BHA between September 2016 and September 2020, all of whom were operated on by the same surgeon. These patients were divided into two groups - those who received SINB and those who did not. The SINB procedure was performed for all patients after January 2018, spanning a period of 2 years and 7 months.

During the BHA procedure, all patients received a standard dose of 0.2 ml/kg of bupivacaine (Heavy MarcaineTM, AstraZeneca, England) intrathecally under spinal anesthesia.

2.2 Participants

In our study, we conducted a retrospective review of the medical records of 87 patients who had undergone BHA for fragility femoral neck fracture at Busan Medical Center between September 2016 and September 2020. The study was approved by the Public Institutional Bioethics Committee designated by the MOHW, and the Institutional Review Board granted approval under the number P01–202011–21-027.

To ensure the validity of our results, patients were excluded from the study if they met certain criteria, including pre-existing immobility prior to the injury, malunion or nonunion resulting from delayed initial treatment, diagnosis of severe dementia or other psychiatric conditions, or signs of delirium within 24 hours of surgery (Delirium Rating Scale >10). In total, four patients were excluded from the study, as shown in Figure 1.

Figure 1.

Flow chart of patient’s registration.

2.3 Interventions

Group 1 comprised of the intervention group receiving the saphenous, femoral, and lateral femoral cutaneous nerve blocks (SINB), while Group II was designated as the control group and did not receive any blocks. All SINBs were performed by a single experienced orthopedic surgeon immediately prior to surgery and repeated thrice postoperatively at 12-hour intervals. A 5-cm long, 5–12 MHz linear probe (LOGIQ e, GE, Boston, USA) and 22G spinal needle were used for the nerve blocks under ultrasound guidance. The femoral, obturator, and lateral femoral cutaneous nerves were each blocked with 7.5, 4, and 4 ml respectively of 0.75% ropivacaine mixed with 7.5, 4, and 4 ml of 1% lidocaine at a 1:1 ratio, which is similar to the method used in a previous study. A sensory test including a pin prick test was performed to confirm the efficacy of the blocks. Premedication included 200 mg of Celebrex (celecoxib; Pfizer, NY, USA) and no additional local anesthetics or analgesics were given during surgery.

Postoperative pain management included patient-controlled intravenous analgesia, consisting of a mixture of 2 mg butorphanol tartrate (Myungmoon Pharm., Seoul, Korea), 50 mg tramadol hydrochloride (Yuhan Corp., Seoul, Korea), and 30 mg ketorolac tromethamine (Hanmi Pharm., Seoul, Korea) mixed in 100 mL of saline, with a background infusion rate of 0.05 ml/hr., bolus of 0.2 ml, and lockout of 8 minutes. This regimen was calculated as 19 MME (morphine milligram equivalent), and the number of doses administered was recorded by checking the volume remaining on the 3rd postoperative day. Rescue analgesics (50 mg of Tramadol or 90 mg of Diclofenac) were administered to patients as required for postoperative pain control, and anti-emetic injection was only given to those who exhibited symptoms of nausea and vomiting.

Patients were instructed on straight leg raising exercises, knee flexion/extension, and ankle dorsiflexion/plantarflexion exercises prior to surgery and encouraged to continue these exercises postoperatively to facilitate rehabilitation. Additionally, patients were educated on postural changes and were provided with medical compression stockings throughout their hospital stay to help prevent postoperative complications.

2.4 Outcome assessments

The post-operative pain intensity was assessed using the visual analogue scale (VAS) at 6, 12, 24, 48, and 72 hours after the surgery. The medical staff provided a detailed explanation of the meaning of VAS before the initial measurement. The number of doses administered through patient-controlled analgesia (PCA) was recorded for the first 72 hours, along with the amount of rescue analgesics. Additionally, the number of cases of nausea and vomiting was recorded from the electronic medical record. Koval classification grade (ambulatory ability I-VII), T-cane walking (days until the patient was able to walk with the aid of a T-cane after the operation), local complications due to SINB, general postoperative complications (pressure sore, pneumonia, deep vein thrombosis, postoperative nausea and vomiting, delirium), and duration of hospitalization were also compared.

2.5 Statistical methods

The statistical analysis was carried out using the SPSS version 22.0 software (IBM Corporation, Armonk, NY). Patient characteristics were evaluated using frequency analysis and cross analysis. The t-test was used to determine any differences in clinical outcomes and patient demographics between the two groups. Power analysis was conducted, which revealed an effect size of 0.5, statistical significance level of 0.05, and statistical power of 0.90 for both groups.

3. Results

The two groups did not differ significantly in terms of age (Group I: 57–88, Group II: 59–86), gender, sex, BMI (kg/m²), Charlson Comorbidity Index (CCI), VAS measured in the ward on the day of admission, koval classification grade, blood loss, or urine output. However, the operative time was longer in Group II by an average of 8.58 minutes (Table 1). Group I had significantly lower subjective pain scores compared to Group II at 6, 12, 24, and 48 hours after BHA (p < 0.05). However, there were no significant differences in post-operative VAS scores at 72 hours (Table 2).

	I‡(n = 42)	II§(n = 41)	p-value
Mean Age (years)	76.24	77.49	0.236
Gender
Male	17	14	0.846
Female	25	25
Mean BMI*(kg/m^2)	22.08	22.05	0.484
Mean CCI†	12.45	13.36	0.26
Mean VAS measured in ward on the day of admission	6.76 (1.84)	6.87 (1.75)	0.36
Koval classification (Grade)
I; II; III; IV; V; VI; VII	27; 6; 2; 3; 1; 1; 2	29; 3; 0; 6; 0; 2; 1	0.262
Mean Operation time (min)	131.57	140.15	0.005*
Mean Blood loss (ml)	343	279	0.065
Mean Urine output (ml)	360.02	279.67	0.051

Table 1.

Patient demographics.

^*

BMI: Body mass index.

^†

CCI: Charlson Comorbidity Index.

^‡

I: 3 Nerves block by continuous injection group.

^§

II: Control group (No injection).

*

Significant difference between Group I and Group II.

	I‡(n = 42)	II§(n = 41)	p-value
6 hours	1.71 (0.21)	7.38 (2.30)	0.000*
12 hours	3.81 (0.30)	6.49 (1.57)	0.000*
24 hours	1.93 (0.17)	6.41 (1.20)	0.000*
48 hours	3.45 (1.28)	5.82 (1.62)	0.000*
72 hours	4.52 (0.45)	4.62 (0.51)	0.28

Table 2.

VAS* for post-operative (mean, standard deviation).

^*

VAS: Visual analog scale at.

^†

Hours Post-op: Hours of the post-operative.

^‡

I: 3 Nerves block by serial injection group.

^§

II: Control group (No injection).

*

Significant difference between Group I and Group II.

In terms of pain management, Group I used a smaller volume of PCA solution (65.72 mL) in the first 72 hours after surgery compared to Group II (83.90 mL). The number of injections administered by PCA was also significantly lower in Group I, with an average of 0.65 injections for Group I patients and 0.88 injections for Group II patients (Table 3).

	I†(n = 42)	II‡(n = 41)	p-value
PCA* consumption (ml)	65.72 (8.78)	83.90 (18.39)	0.000*
Additional analgesic injection(number of injection)	0.65	0.88	0.029*

Table 3.

PCA* consumption for post-operative 72 hours (mean, standard deviation).

^*

PCA: patient controlled analgesia.

^†

I: 3 Nerves block by serial injection group.

^‡

II: Control group (No injection).

*

Significant difference between Group I and Group II.

The incidence of pressure sores, pneumonia, and deep vein thrombosis did not differ significantly between the groups. However, the incidence of postoperative nausea and vomiting (PONV) (0.00%) and delirium (0.07%) in Group I was lower than that in Group II (0.15 and 0.24%, respectively). There were no reports of any local complications due to SINB or any reports of block failure. The length of hospital stay and T-cane walking start day after the operation did not differ significantly between the groups (Table 4).

	I*(n = 42)	II†(n = 41)	p-value
General Complications Pressure sore			0.571
	1	2
Pneumonia	2	3	0.875
DVT‡ Postoperative nausea and vomiting; Delirium	0; 0; 3	0; 6; 10	-; 0.013*; 0.032*
Local Complications	0	—	—
Length of stay (day) (mean)	39.26	44.54	0.073
T-cane walking (day) (mean)	11.52	11.97	0.40

Table 4.

Complications & Length of stay & ambulation function.

^*

I: 3 Nerves block by serial injection group.

^†

II Control group (No injection).

^‡

DVT: Deep vein thrombosis.

^#

HHS: Harris Hip Score.

*

Significant difference between Group I and Group II.

4. Discussion

The limitation of single injection nerve block is that it can manage only post-operative pain after BHA up to 12 hours. Serial injection nerve blocks effectively extended the duration of analgesic effects necessary for postoperative pain management. In this study, SINB can achieve adequate pain control not only for 12 hours after surgery but also up to 48 hours after surgery. Besides pain control, general complications such as the incidence of PONV and delirium were remarkably reduced due to SINB effect. These results are quite different from other studies which demonstrated no significant difference in delirium rate in CFNC (Continuous Femoral Nerve Catheter) treatment [12]. Considering the etiology of delirium is complex and multifactorial, it is remarkable that controlling pain adequately can be a powerful management of delirium.

Performing triple nerve blocks every 12 hours for 2 days can be a labor-intensive process. To address this issue, we implemented a manual approach for serial triple nerve blocks. Prior to the BHA surgery, triple nerve blocks were performed with ultrasound guidance just before spinal anesthesia in the operating room. Following the surgery, we conducted rounds approximately 12 hours later (following the first triple nerve blocks) and performed the triple nerve block at the patient’s bedside with the assistance of the ward nurse. On postoperative day 1, we conducted wound dressing and repeated the triple nerve blocks at the bedside. Finally, the last set of triple nerve blocks were performed during the afternoon rounds, following the same protocol as before.

Several advantages of favoring longer-acting regional block techniques were reported besides our study. Based on work by Farrar et al. with the utilization of continuous femoral nerve catheter, 60% pain score was reduced preoperatively, as well as 50 and 54% lower pain scores on postoperative day 1 and 2, respectively [14].

Our study confirms the results of previous studies that serial femoral nerve blocks not only decrease average patient-reported pain scores, morphine consumption in the pre- and postoperative period, but also lower the rate of opioid-related side effects [12]. This is consistent with findings that controlling pain and reducing opioid requirement is associated with reductions in PONV and delirium and adds to the body of evidence that regional techniques can decrease post-operative complications.

Moreover, also found by the chart notes, patients were able to perform postoperative breathing and rehabilitation exercises [12, 13]. However, unlike previous studies we could not find that more patients were discharged with or without home health services [12].

The present study aimed to assess the efficacy of single-injection nerve block (SINB) for managing pain during BHA surgery. Although the study showed that SINB provided effective pain relief, it had certain limitations that require further exploration.

One such limitation was the retrospective nature of the study, indicating the need for a randomized, double-blind trial to validate the results. Additionally, the potential influence of antiemetic medication on postoperative pain and narcotic-related side effects was not considered.

The cost of multiple injections required for SINB was another limiting factor, particularly in patients with low income. Additionally, the procedure duration and the risk of local complications such as infection and hematoma were potential concerns.

The study found that temporary weakness in the quadriceps muscles [11, 12, 13] caused by femoral nerve block did not hinder patients undergoing BHA surgery, as they were advised to stay in bed for 72 hours and partial weight-bearing was recommended [15, 16, 17, 18] for several weeks after the surgery. Ankle dorsiflexion and plantarflexion exercises were also utilized to prevent deep vein thrombosis.

Although there was no statistically significant difference in hospitalization duration between the two groups, a trend towards shorter hospitalization was observed in the SINB group. Future studies could investigate pain control using continuous femoral nerve catheter dwelling or explore the impact of T-cane walking initialization day on early mobilization between the two groups.

5. Conclusion

Administration of sequential lower limb nerve blocks with the guidance of ultrasound not only yields superior pain relief during the early post-operative phase following BHA, but also has the potential to maintain pain relief, resulting in reduced consumption of narcotics and mitigating associated adverse effects, such as post-operative nausea and vomiting (PONV) and delirium.

Funding

No Funding has been received.

Competing interests

All the other authors declare no conflict of interest.

Consent for publication

Not applicable.

Declarations

Ethics approval and consent to participate

1. Ethics approval was obtained from the Institutional Review Board “Public Institutional Review Board Designated by Ministry of Health and Welfare” (Approval # P01–202201–01-026). The study was carried in accordance with relevant guidelines and regulations, such as Declaration of Helsinki.

2. Not applicable.

   The need for Informed Consent was waived by the Public Institutional Review Board Designated by Ministry of Health and Welfare. All methods were performed in accordance with the relevant guidelines and regulations.

Availability of data and materials

Data availability

The datasets generated during and/or analyzed during the current study are not publicly available due to the IRB (“Public Institutional Review Board Designated by Ministry of Health and Welfare”) guideline, it is stipulated that the patient’s personal data should be discarded within 6 months after data collection.