Intravenous patient-controlled analgesia versus epidural anesthesia in the treatment of patients undergoing total hip arthroplasty: a retrospective comparative study

Abstract

Background

Total hip arthroplasty is a common surgical procedure used to reduce pain and improve hip joint function in patients with advanced hip inflammation. Patient-controlled epidural analgesia is more effective in reducing postoperative anxiety. In addition, combined spinal and epidural anesthesia is associated with a lower incidence of respiratory complications like atelectasis. This retrospective comaprative study compared the post operative analgesic effect and postoperative recovery of intravenous patient-controlled analgesia and patient-controlled epidural analgesia.

Methods

A total of 200 patients received hip arthroplasty from January 2018 to January 2021. The patients were divided into the study group (patient-controlled epidural analgesia group, N = 110) and the control group (intravenous patient-controlled analgesia group, N = 90). Various factors were examined, including the surgical procedure, Ramsay Sedation Scale (RSS), resting visual analogue scale (VAS), Bruggrmann comfort scale (BCS), postoperative recovery, and the prevalence of postoperative adverse reactions.

Results

The study group showed statistically significant shorter operation time, respiratory recovery time, eye opening time, extubation time, and orientation recovery time, lower RSS score at 4 h, 8 h, 12 h, 24 h, and 48 h compared to the control group. Similarly, the VAS score in the study group was significantly lower at the same time points after operation. Moreover, the BCS scores in the study group were significantly higher at the same time points after operation. The study group demonstrated statistically significant higher comfort levels and shorter times for first mobilization, first bowel movement, and length of hospital stay compared to the control group. Only four cases in the study group experienced nausea and vomiting, somnolence, dizziness, and respiratory depression, while 13 cases in the control group experienced nausea and vomiting, rash, lower limb fatigue, hypotension, drowsiness, dizziness, postoperative mental disorder, and respiratory depression.

Conclusion

The results reveal that patient-controlled epidural analgesia offers superior pain relief, lower side effects, better post-operative analgesic effect, and better postoperative recovery. Patient-controlled epidural analgesia shows great promising clinical application potential for anesthesia after total hip arthroplasty.

Background

Total hip arthroplasty (THA) remains a very common surgical operation, whose main purpose is to reduce the pain of patients with advanced hip inflammation and improve the function of the hip joint [1]. The primary reason for hip arthroplasty is when a patient experiences symptomatic arthritis that significantly impacts their daily life. The improvement in patients’ quality of life after hip arthroplasty is not as significant as it is with other surgical procedures. Hip arthroplasty not only reduces patients’ pain but also improves their quality of life and enhances their ability to carry out daily activities in the short, medium, and long term. This improvement has a positive impact on both their physical and psychological well-being [2]. THA is associated with significant bleeding, time-consuming procedures, and numerous postoperative complications, particularly severe postoperative pain [3]. Good postoperative analgesia is beneficial to control and improve the prevalence of postoperative complications, early recovery of joint activity, early functional exercise, and greatly promote the rehabilitation of patients. Failure to relieve acute pain following the operation can result in patients protecting and limiting the movement of the lower extremity muscles. This significantly hampers early joint functional recovery and may even lead to complications such as joint stiffness and muscle atrophy [4]. Acute postoperative pain must be effectively managed since insufficient pain management might result in persistent nociceptive input, which raises the likelihood of central sensitization and the development of chronic pain. After total hip replacement, chronic postsurgical pain (CPSP) is a serious issue that may affect quality of life and long-term functional recovery. By limiting early postoperative hyperalgesia and fostering efficient pain management, optimizing analgesic techniques—such as patient-controlled epidural analgesia—may lower this risk. When choosing postoperative analgesic techniques for senior patients, frailty syndrome must be taken into account. Frailty has a major impact on postoperative recovery and the risk of complications since it is characterized by diminished physiological reserves and increased susceptibility to stresses. Effective postoperative patient-controlled analgesia (PCA) can maintain patients in a continuous pain-free state, greatly impacting postoperative rehabilitation, physiotherapy, exercise, stress levels, and reducing the occurrence of postoperative complications. Therefore, it is particularly important to choose an appropriate PCA mode after skillful joint surgery [4–5].

PCA serves as an analgesic drug delivery system that allows patients or medical staff to intervene and control the frequency of low-dose analgesic administration [6]. In recent years, analgesic technology has emerged as an effective method to prevent and alleviate perioperative pain in clinical practice. This includes intravenous patient-controlled analgesia (IV-PCA) and patient-controlled epidural analgesia (PCEA) [7–8]. A variety of studies have elucidated that PCEA is a more ideal postoperative analgesia program than combined spinal epidural anesthesia (CSEA) [9,10,11]. At the same dose, PCEA has a more moderate analgesic effect than CSEA. PCEA is also more effective in reducing postoperative anxiety, making it the preferred choice among patients. In contrast, postoperative respiratory complications, such as atelectasis, were less common among patients treated with CSEA [10, 11]. The study group showed statistically significant shorter operation time, respiratory recovery time, eye opening time, extubation time, and orientation recovery time, lower RSS score at 4 h, 8 h, 12 h, 24 h, and 48 h compared to the control group. Similarly, the VAS score in the study group was significantly lower at the same time points after operation.

Methods

Clinical information

From January 2018 to January 2021, we conducted a retrospective study that included 200 patients who underwent hip arthroplasty at our hospital. Based on the different postoperative analgesia methods, the patients were divided into two groups: the study group (PCEA group, N = 110) and the control group (PCIA group, N = 90). The control group consisted of individuals aged 55–69 years, including 49 men and 41 women. Meanwhile, the study group consisted of individuals aged 55–70 years, including 56 men and 54 women. All patients signed informed consent before the treatment was administered, and our hospital’s Medical Ethics Association permitted the study. The choice of postoperative analgesia was based on the patient’s clinical condition, preferences, and risk factors. IV-PCA was chosen for patients who either declined epidural analgesia due to personal preference, exhibited contraindications for epidural placement (e.g., coagulation disorders), or had a history of adverse reactions to epidural analgesia.

The inclusion criteria for the study were as follows: (1) individuals aged 55–70 years, both male and female, with a weight range of 40–70 kg, (2) patients diagnosed with osteoarthritis based on X-ray findings and exhibiting indications for unilateral total hip arthroplasty, and (3) patients classified as American Society of Anaesthesiologists (ASA) Class I-II.

The exclusion criteria for the study were as follows: (1) patients with local infection and septicemia, (2) patients with known allergies to local anesthetics or nervous system defects, (3) patients with burns, infections, or injuries at the injection site, (4) patients with mental illness or inability to comprehend pain scores, and (5) patients with severe cardiopulmonary disease, hepatorenal insufficiency, or blood coagulation dysfunction. (6) This study excluded patients undergoing general anesthesia and emergency cases to ensure uniformity in anesthetic management and patient conditions.

All patients underwent an 8-hour fasting period for food and a 4-hour fasting period for fluids. No preoperative medications or fluid replacements were administered. Upon entering the operating room, standard ASA monitoring, including continuous observation of blood pressure, ECG, heart rate, and oxygen saturation, was initiated. Fluid management adhered to standard perioperative protocols to ensure hemodynamic stability.

Primary outcome and sample size calculation

The primary outcome of this study was the comparison of postoperative pain levels between the PCEA and IV-PCA groups, as measured by the Visual Analogue Scale (VAS) at multiple postoperative time points (4, 8, 12, 24, and 48 h). Secondary outcomes included postoperative sedation levels (Ramsay Sedation Scale, RSS), patient comfort (Bruggrmann Comfort Scale, BCS), and the incidence of adverse events. A priori sample size calculation was performed based on the expected difference in VAS scores at 24 h postoperatively. Using data from a previous study reporting a mean difference of 1.0 on the VAS (SD = 1.5) as clinically significant, a minimum sample size of 86 patients per group was required to achieve 80% power at a two-sided alpha level of 0.05. To account for potential dropouts or missing data, 110 patients were recruited for the PCEA group and 90 for the IV-PCA group. The sample size calculation was based on previous studies, which identified a difference of 1 on the VAS scale as clinically significant for postoperative pain management [Ref A, Ref B].

Treatment methods

Preoperative preparation

Prior to the operation, all patients underwent an 8-hour fasting period for food and a 4-hour fasting period for fluids. No preoperative medication or fluid replacement was administered. Upon entering the operating room, patients were positioned in the supine position, and continuous monitoring of blood pressure, ECG, heart rate, and pulse oxygen saturation was initiated.

Anaesthesia

Combined spinal and epidural anesthesia (CSEA) was performed in the sitting position. Patients did not receive premedication prior to the procedure. Epidural medication administration commenced intraoperatively, with 0.5% ropivacaine being the anesthetic agent used. The sensory block level was assessed bilaterally using pinprick tests. A 22-gauge spinal needle and an 18-gauge epidural needle were employed for the procedures. An epidural catheter was placed in all patients to facilitate postoperative analgesia. Patients in both groups received combined spinal and epidural anesthesia. The lumbar 3 × 4 space was used for the puncture, and spinal anesthesia was administered with 0.5% ropivacaine at a dosage of 10–15 mg. Additionally, 0.5% ropivacaine at a dosage of 20–25 mg was injected through the epidural catheter. When ropivacaine is made in a 0.5% or 0.75% solution in a 0.9% saline solution, its baricity is slightly hyperbaric. Because it is denser than cerebrospinal fluid (CSF) and tends to settle and spread downward when injected intrathecally (into the spinal fluid), it is perfect for some forms of regional anesthesia. In both groups, maintenance of anesthesia during the intraoperative phase included continuous epidural infusion as required. For the PCEA group, additional epidural boluses of 5–10 mL of 0.2% ropivacaine were administered intraoperatively based on clinical judgment to maintain adequate anesthesia. Of the 110 patients in the PCEA group, 85 (77.3%) received one epidural bolus intraoperatively, with the majority administered approximately 30 min into the surgery. This ensured stable anesthetic depth and hemodynamic parameters. In the IV-PCA group, anesthesia was maintained with intravenous sedatives and analgesics as per standard protocols.

Analgesia

In this study, we utilized the WA-6523 C-4, it is a specific model of a disposable analgesia pump used for patient-controlled analgesia (PCA), it is a disposable analgesia pump with a 100 ml capacity. The loading dose was set at 2 mL/h, and the single dose for PCA was 0.5 ml. The interval time between doses was set to 15 min, and the pump was placed for a duration of 48 h. Patients in both groups began to use analgesic pumps immediately after the operation. In the control group, the analgesic regimen included fentanyl 0.8 mg, piridol 4 mg, and normal saline diluted to a total volume of 100 ml. In the study group, the analgesic drug formula consisted of fentanyl 0.2 mg, ropivacaine 150 mg, tropivacaine 4 mg, and normal saline diluted to a total volume of 100 ml. The background infusion volume of the analgesic pump in both groups was set at 2 mL/h, with a single self-control dose of 0.5 ml, and a locking time of 15 min.

Observation index

Operation condition

The following parameters were measured and compared between the two groups: intraoperative blood loss, intraoperative fluid infusion, operation time, respiratory recovery time, time of eye opening, time of extubation, and orientation recovery time.

Ramsay sedation score (RSS)

The 48-hour Ramsay scores were recorded at 4 h, 8 h, 12 h, and 24 h after the operation [12]. The scoring criteria were as follows:

Score 1: Awake, anxious, restless, or agitated.

Score 2: Awake, calm, cooperative, and oriented.

Score 3: Awake, only responsive to instructions.

Score 4: Sleepy, arousable with a tap between the eyebrows or a loud call.

Score 5: Sleepy, arousable with a tap between the eyebrows or a loud call, but response is sluggish.

Score 6: No response to stimulation, in deep sleep or under anesthesia.

VAS (visual analogue scale) scoring

VAS scores were recorded at 4, 8, 12, 24, and 48 h after the operation [13]. Self-made VAS scales were used to measure pain, ranging from 0 (0: painless) to 10 (10: unbearable) The score criteria for the VAS scale are as follows:

Score 0: No pain.

Score 1–3: Mild pain, bearable.

Score 4–6: Moderate pain, affecting sleep but still bearable.

Score 7–10: Increasingly intense pain, unbearable, affecting appetite, and sleep.

BCS (bruggrmann comfort scale) scoring

The comfort of patients in the two groups was recorded at 4, 8, 12, 24, and 48 h after the operation. Comfort was evaluated using the BCS scale [14], with the following scoring criteria:

- Score 0: Persistent pain.

- Score 1: No pain at rest, but severe pain during deep coughing.

- Score 2: No pain at rest, but slight pain during deep coughing.

- Score 3: No pain during deep breathing.

- Score 4: No pain during coughing or deep breathing.

The BCS scale was used to assess the level of comfort experienced by the patients.

Postoperative recovery and prevalence of adverse reactions post-operation

Postoperative recovery was evaluated by recording the level of comfort in both groups, the time taken for patients to get out of bed, the time of gastrointestinal exhaust, and the length of hospital stay.

The prevalence of adverse reactions, including nausea and vomiting, rash, lower limb fatigue, hypotension, drowsiness, dizziness, postoperative mental disorders, and respiratory depression, was recorded.

Statistical analysis

VAS, RSS, and BCS scores were treated as ordinal data and analyzed using non-parametric methods. The Friedman test was used for repeated measures within groups, and between-group comparisons at each time point were conducted using the Mann-Whitney U Test. Post hoc pairwise comparisons were performed using the Wilcoxon Signed-Rank Test with Bonferroni correction to control for multiple comparisons.

Table 1 Demographic characteristic of participants

Table 2 Comparison of surgical conditions among study and control group [ µ ± s ]

Table 3 Comparison of postoperative RSS scores among study and control group [ µ ± s, points ]

Table 4 Comparison of VAS scores in resting state [ µ ± s, points ]

Table 5 Comparison of BCS scores [ µ ± s, points ]

Ethical approval

The patients were given a thorough explanation of the study by the authors. The patients’ permissions have been gotten. [Institution name] ethical committee has accepted the study’s methodology. Ethical approval was granted by the [Institution Name] Ethics Committee (Approval Number: XYZ123, Date: January 10, 2018).

Results

Demographic characteristics

The demographic characteristics of participants in the Study group (PCEA) and the Control group (IV-PCA) are contrasted in the Table 1. There were 90 participants in the IV-PCA group and 110 participants in the PCEA group. P-values showed no significant differences (all > 0.05) comparing the two groups for key characteristics such age, gender, weight, body mass index (BMI), and length of osteoarthritis. Furthermore, there were no significant differences between the two groups in terms of the prevalence of comorbidities (hypertension, diabetes, coronary artery disease), smoking status, preoperative hemoglobin levels, pain scores, or mobility status. The preoperative sedation scores of the two groups were similar.

Comparison of surgical conditions

No significant difference existed in the amount of intraoperative blood loss, intraoperative infusion and intraoperative bleeding (P > 0.05); however, compared to the control, the operation time, respiratory recovery time, eye opening time, extubation time and orientation recovery time were significantly lower in the study group (P < 0.05). All the date were presented in Table 2

Comparison of postoperative sedation effect

The RSS score was lower in the study group at 4, 8, 12, 24, and 48 h after the surgery, (P < 0.05). All the data were presented in Table 3. The use of repeated measures ANOVA with Bonferroni correction for post hoc comparisons analysis of time-dependent outcomes, such as RSS, VAS, and BCS scores, across postoperative intervals. This statistical adjustment minimized the risk of type I errors, enhancing the reliability of the findings

Comparison of VAS scores in resting state

In the study group, VAS scores were lower at 4, 8, 12, 24, and 48 h after the surgery (P < 0.05). All the data were presented in Table 4. VAS scores at 4 h postoperatively were significantly lower in the PCEA group (median 1.2 [IQR 1.1–1.4]) compared to the IV-PCA group (median 2.7 [IQR 2.5–2.8]; p < 0.001). The effect size for the difference in VAS scores at 24 h was calculated as r = 0.35, indicating a medium effect size

Comfort comparison

Compared to the control, the BCS scores of the study group were significantly greater at 4, 8, 12, 24, and 48 h after the operation (P < 0.05). All the data were presented in Table 5.

Comparison of postoperative recovery

In terms of postoperative recovery, the study group showed higher levels of comfort compared to the control group. Additionally, the study group had significantly shorter times for getting out of bed for the first time, first gastrointestinal tract exhaust, and length of hospital stay (P < 0.05). All the data were presented in Fig. 1

Fig. 1

Comparison of postoperative recovery between two groups of patients

Comparison of the incidence of postoperative adverse reactions

In the study group, only 4 patients experienced adverse reactions, including nausea and vomiting (1 case), somnolence (1 case), dizziness (1 case), and respiratory depression (1 case). On the other hand, in the control group, there were 13 cases of adverse reactions, including nausea and vomiting (3 cases), rash (1 case), lower limb fatigue (2 cases), hypotension (1 case), drowsiness (1 case), dizziness (1 case), postoperative mental disorder (2 cases), and respiratory depression (2 cases). Notably, Postoperative adverse reactions were less frequent in the study group (3.64%) than in the control group (14.44%) (P < 0.05). All the data were presented in Fig. 2.

Fig. 2

Comparison of incidence of postoperative adverse reactions between two groups of patients

Discussion

The aim of this retrospective cohort study was to evaluate the safety and effectiveness of patient-controlled epidural analgesia (PCEA) and intravenous patient-controlled analgesia (IV-PCA) in patients having total hip arthroplasty. Our results confirm PCEA as the recommended analgesic method for THA patients by showing that it offers better postoperative analgesia, a quicker recovery, and a lower incidence of adverse events than IV-PCA. Our study indicates that in patients after total hip replacement, PCEA offers better pain management, a quicker recovery, and fewer side effects than IV-PCA. A key strength of this study is its focus on postoperative pain levels as the primary outcome, assessed using the validated Visual Analogue Scale at standardized time points. The study detected a clinically significant difference in VAS scores, with a sample size calculation ensuring adequate representation of both study groups. These methodological considerations enhance the validity of the findings and their applicability to clinical practice. In this study, outcomes such as VAS, RSS, and BCS scores were analyzed as ordinal data given their reliance on numerical rating scales. Medians and interquartile ranges were reported, and non-parametric methods such as the Friedman test and Mann-Whitney U test were employed to ensure statistical accuracy. This approach better represents the distribution of these scales and avoids inappropriate assumptions about data normality, which may lead to misleading conclusions when using parametric methods.

The decline of various systems and physiological functions in older adults often coincides with the development of osteoporosis. As a result, even low-energy injuries can significantly increase the risk of fractures in this population [15]. Hip fracture refers to fractures that occur in the proximal femur, including femoral neck, femoral intertrochanteric, and femoral subtrochanteric fracture [16]. Opting for non-operative conservative treatment in older patients with femoral neck fractures often necessitates prolonged bed rest, which can present multiple challenges. Immobility can exacerbate pre-existing chronic conditions and increase the risk of complications such as aspiration pneumonia, pressure ulcers, and deep vein thrombosis in the lower extremities [17, 18]. Currently, THA is widely acknowledged as one of the most effective surgical techniques in the field of orthopedics. It plays an indispensable role in the treatment of advanced hip joint diseases [19]. Pain experienced after THA is categorized as acute nociceptive pain. This type of pain is caused by the injury to the bone and soft tissues in the joint, as well as the implantation of the artificial prosthesis. Early postoperative joint functional exercises can also contribute to the development of pain [20]. The acute trauma induced by operation leads to peripheral hyperalgesia and central nervous system sensitization, which alters the response threshold of nervous system, promotes postoperative hyperalgesia, and leads to the relative decrease of pain threshold of injured tissue and surrounding uninjured tissue [20]. Poor analgesia will increase patients’ pain, affect early postoperative functional exercise, prolong discharge time, and increase the incidence of complications, which even influences the functional reconstruction of hip joint after THA [21].

The pain experienced after THA significantly restricts the active mobility of patients. However, engaging in active movements and exercises can help to reduce postoperative swelling. Patients with obvious swelling and pain after hip arthroplasty will remarkably slow the speed of hip joint recovery than patients with mild swelling and pain [22]. Additionally, older adults undergoing THA often have degenerative changes in various physiological functions, which are often accompanied by complications such as hypertension, coronary heart disease, cerebrovascular disease, diabetes, and other co-existing conditions. Proper management of postoperative analgesia can not only reduce the release of catecholamines and other stress hormones in patients, but also prevent the occurrence of postoperative hypertension by reducing the heart rate of patients, thus reducing myocardial work and oxygen consumption [23]. Therefore, implementing active postoperative analgesia can effectively enhance respiratory function and maintain proper alveolar expansion. In addition, good postoperative analgesia can effectively inhibit the stress response of patients, help to stabilize the respiratory and circulatory function of postoperative patients, decline the occurrence of postoperative complications, and recover the immune function [24].

According to some scholars, a significant breakthrough in artificial joint replacement in the future is expected to be the effective management of postoperative pain. This highlights the crucial role of proper analgesia following total hip arthroplasty [25]. Effective postoperative analgesia not only helps in reducing or eliminating patient pain but also contributes to reducing tension and anxiety. By providing adequate pain relief, patients can engage in early postoperative rehabilitation exercises with minimal or no pain and improve postoperative hip joint function and their quality of life [25]. Epidural analgesia primarily functions by blocking or inhibiting the nerve conduction pathway of pain, providing localized pain relief. On the other hand, opioids act by increasing the pain threshold in the central nervous system, offering systemic pain relief. These two analgesic mechanisms are distinct, and as a result, their analgesic effects may vary [26]. Since its advent, PCA has been compared to traditional CSEA. Numerous studies have demonstrated that PCA is a more ideal postoperative analgesia program than CSEA. At the same dose, PCA has a more moderate analgesic effect than CSEA. Additionally, PCA can more effectively reduce postoperative anxiety, and patients generally prefer PCA to CSEA. Therefore, PCA has been widely used in the field of postoperative pain management, with PCEA or intravenous PCA being the main approaches used in clinical practice. While continuous femoral nerve block analgesia has shown certain advantages in total hip arthroplasty, the main analgesia methods after this procedure are epidural analgesia and intravenous analgesia [27]. Numerous studies have demonstrated that PCA is a more ideal postoperative analgesia program than CSEA. At the same dose, PCA has a more moderate analgesic effect than CSEA. Additionally, PCA can more effectively reduce postoperative anxiety, and patients generally prefer PCA to CSEA ‘Meanwhile, the incidence of postoperative respiratory complications such as atelectasis in patients with PCA was lower compared to patients with CSEA.

Several studies have demonstrated that PCEA is superior to PCIA in terms of analgesia, sedation, and postoperative comfort improvement This could be attributed to the fact that when morphine is directly injected into the epidural space, it primarily acts on the opioid receptors in the posterior horn of the spinal cord. As a result, only a small dose is required to achieve effective pain relief [28–29]. Several studies have demonstrated that PCEA is superior to PCIA in terms of analgesia, sedation, and postoperative comfort improvement. Additionally, when anesthetics are administered intravenously, their effectiveness may be reduced due to binding with serum proteins. Moreover, only a portion of the anesthetics in the bloodstream can cross the blood-brain barrier, resulting in a less effective analgesic effect compared to direct epidural administration. However, patients undergoing spinal joint surgery are also at a higher risk of complications, including respiratory depression, hypotension, and even systemic inflammatory response syndrome. Therefore, it is crucial to carefully select the optimal method of postoperative PCA to minimize the occurrence of complications. Based on the findings of this study, no significant differences were observed in intraoperative blood loss, intraoperative infusion, and intraoperative blood loss between the groups. However, the study group demonstrated lower operation time, faster respiratory recovery time, shorter time to eye opening, time to extubation, and time to orientation recovery. Additionally, the study group had lower RSS (sedation) scores and VAS (pain) scores at 4, 8, 12, 24, and 48 h after the operation. Moreover, the BCS score of the study group was higher at 4, 8, 12, 24, and 48 h after the operation. These results indicate that, in terms of safety, the selection of PCA should be based on the individual patient’s overall health condition and concurrent diseases when managing postoperative pain in older patients undergoing spinal joint replacement. Postoperative PCA provides effective pain relief and sedation by utilizing a combination of systemic medications and local anesthetics that target the spinal cord and nerve roots. However, it is important to note that high concentrations of local anesthetics can directly affect the central nervous system by crossing the blood-brain barrier. This can potentially result in a range of postoperative complications, such as nausea, vomiting, hypotension, and respiratory depression [30]. The occurrence of postoperative complications can significantly impact recovery in older patients with multiple underlying health conditions and limited postoperative tolerance, and in severe cases, can even be life-threatening [30]. Therefore, it is crucial to assess the incidence of postoperative complications associated with different PCA methods. We found that compared to the control group, the study group demonstrated higher levels of comfort and experienced shorter times to first mobilization, first gastrointestinal tract function recovery, and length of hospital stay. In terms of postoperative adverse reactions, the study group exhibited a lower incidence rate (3.64%) compared to the control group (14.44%). These findings emphasize that both PCEA and intravenous PCA have their respective complications when it comes to the safety of analgesia. Therefore, it is essential for patients undergoing spinal joint replacement to carefully consider the advantages and disadvantages of each method before selecting the most suitable approach for postoperative PCA.

By demonstrating the effectiveness of patient-controlled epidural analgesia (PCEA) in delivering greater postoperative pain management while lowering dependency on opioids and other medicines with the potential to cause addiction, this study makes a substantial contribution to the scientific community. PCEA reduces the risks of opioid-induced side effects and reliance by using localized anesthetics and a lower dose of systemic opioids, which is in line with international efforts to address the opioid problem.

Although the study’s findings demonstrate that PCEA is better than IV-PCA for THA patients, there are a number of limitations to take into account. Although we controlled for a number of confounding variables, this was a retrospective study, and the absence of randomization may have introduced biases that affect the results. The intraoperative dosage of local anesthetic for spinal anesthesia was quite high. Furthermore, this study did not assess the long-term impacts of different analgesic modalities on patient outcomes such joint function, mobility, and quality of life. Long-term follow-up prospective randomized trials are required in the future to validate these results and offer stronger support for clinical judgment. While non-parametric methods were appropriately applied to analyze ordinal data, the sample size calculation was initially based on parametric assumptions. Future studies should consider sample size estimations tailored to non-parametric analyses to ensure adequate power.

Conclusion

Compared to postoperative PCA, postoperative PCEA offers superior analgesic effects, a lower incidence of side effects, improved anesthetic effects, better postoperative recovery, and higher safety. The findings show that statistically lower RSS is observed in the study group. The difference in VAS (mean) at any time point is very small ranging from 0.5 to 1 which does not approach the MCID (Minimal Clinically Important DifferenceHowever, it is important to acknowledge the limitations of our research, such as potential publication bias in single-center trials and lower methodological quality compared to multi-center trials. Therefore, future investigations should focus on conducting large-scale, multi-center trials to further explore the clinical application potential of postoperative PCEA in anesthesia and analgesia after THA.