Post-Operative Spinal Block Duration and Pain Relief After Hip Replacement Surgery: Comparing Single-Shot Spinal Ropivacaine and Bupivacaine (ROBUTHA)

Post-Operative Analgesia and Spinal Block Duration Following Total Hip Arthroplasties: Comparison of Single-Shot Intrathecal Ropivacaine and Bupivacaine in a Randomized Double-Blinded Controlled Study

This study aims to determine whether isobaric ropivacaine is more suitable than isobaric bupivacaine for spinal anesthesia in outpatient total hip arthroplasty (THA). The study will evaluate whether ropivacaine allows faster recovery of sensory and motor function while still providing adequate surgical anesthesia and postoperative pain control. Additional aims are to assess the effects of the anesthetic technique on same-day discharge rates, postoperative recovery, urinary retention, opioid consumption, and patient satisfaction after outpatient THA.

Study Overview

• Status: Not yet recruiting
• Conditions: Hip Osteoarthritis; Hip Arthroplasty Replacement; Postoperative Pain After Ambulatory Surgery
• Intervention / Treatment: Drug: Spinal Anesthesia with Ropivacaine 15 mg (5 mg/ml); Drug: Spinal Anesthesia with Bupivacaine 11 mg (5 mg/ml)

Detailed Description

Patients undergoing outpatient total hip arthroplasty (THA) under spinal anesthesia require an anesthetic technique that provides adequate surgical anesthesia while allowing rapid postoperative recovery and same-day discharge. Bupivacaine is currently the most commonly used spinal anesthetic for hip arthroplasty, but its relatively long duration of action may delay recovery of motor and sensory function, prolong post-anesthesia care unit (PACU) stay, and increase the risk of urinary retention. Ropivacaine is a long-acting amide-type local anesthetic with a shorter duration of action and a potentially more favorable safety profile, including lower cardiotoxicity and reduced hemodynamic effects. This study aims to determine whether isobaric ropivacaine is more suitable than isobaric bupivacaine for spinal anesthesia in outpatient THA and to identify the optimal dose of ropivacaine for this surgical setting.

Altogether 176 patients scheduled for elective outpatient unilateral total hip arthroplasty at TYKS ORTO Surgical Hospital will be enrolled in this prospective, randomized, double-blind, controlled phase IV clinical trial. Eligible participants will be between 18 and 80 years of age, with a height of 160-186 cm, ASA physical status I-II, and body mass index below 35 kg/m², in accordance with local outpatient surgery criteria. Written informed consent will be obtained from all participants prior to study inclusion.

Patients will be randomized into two study groups to receive either intrathecal isobaric ropivacaine or intrathecal isobaric bupivacaine for spinal anesthesia. Both participants and investigators will remain blinded to group allocation throughout the study period. Spinal anesthesia will be performed according to standard clinical practice. Patient monitoring and perioperative care will follow institutional protocols routinely used for outpatient joint replacement surgery.

Baseline measurements including heart rate, blood pressure, and oxygen saturation will be recorded before administration of spinal anesthesia. After intrathecal injection, patients will undergo continuous monitoring including blood pressure, pulse, electrocardiography (ECG), oxygen saturation, and assessment of sensory block height. Measurements will initially be recorded every five minutes during the intraoperative period and subsequently at longer intervals after transfer to the ward.

The primary outcome of the study is the time to full recovery of sensory and motor function following spinal anesthesia. Secondary outcome measures include the proportion of patients discharged home as planned on the day of surgery, duration of PACU stay and total hospital stay, postoperative pain intensity measured using the Numerical Rating Scale (NRS; minimum 0, maximum 10, higher scores indicating more severe pain), incidence of urinary retention, time required to achieve adequate surgical anesthesia, adequacy of anesthesia during surgery, incidence of postoperative nausea and vomiting (PONV), postoperative opioid consumption, and patient satisfaction with care and recovery.

Postoperative pain management will follow standard institutional protocols. Pain intensity will be assessed regularly in the PACU and surgical ward using the NRS scale. Additional postoperative opioid analgesics may be administered as clinically indicated. Follow-up telephone interviews will be conducted on postoperative days 2 and 3 to assess recovery at home, pain management, discharge-related challenges, and patient satisfaction.

Bupivacaine and ropivacaine are both widely used amide-type local anesthetics for spinal anesthesia in orthopedic surgery. Their mechanism of action is based on reversible blockade of sodium channels in nerve cells, thereby inhibiting nerve impulse conduction. Ropivacaine has been associated with less cardiotoxicity, reduced central nervous system toxicity, and shorter duration of motor blockade compared with bupivacaine, which may improve suitability for outpatient surgery.

Both study medications are routinely used in clinical practice at TYKS ORTO Surgical Hospital and throughout the Nordic countries. Serious adverse effects are rare and are typically associated with overdose or unintentional intravascular administration. Common effects related to spinal anesthesia include transient hypotension due to sympathetic blockade, urinary retention, post-spinal headache, and temporary back pain. Severe complications such as infection or nerve injury are extremely uncommon. The study specifically aims to evaluate whether shorter-duration spinal anesthesia may reduce delayed recovery and urinary retention while maintaining adequate surgical conditions and postoperative analgesia.

All participant data will be handled confidentially. Personal identifiers will be removed from study documents and replaced with study identification numbers. The code key linking participant identities to study data will be stored separately in a password-protected file accessible only to the research team. Paper records will be maintained in locked facilities at Turku University Hospital, and no identifiable data will be shared outside the study team.

• Study Type: Interventional
• Enrollment (Estimated): 176
• Phase: Phase 4

Contacts and Locations

• Study Contact: Name: Panu Uusalo, MD, PhD; Phone Number: +35823133077; Email: panu.uusalo@varha.fi
• Study Contact Backup: Name: Maarit Rantakokko, MD; Email: maarit.rantakokko@varha.fi

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 18 - 80 years of age
• Scheduled for a primary elective total hip arthroplasty
• Patient must be a candidate for same day discharge
• Informed consent understood and signed
• Patient is 160 - 186 cm tall

Exclusion Criteria:

• Scheduled bilateral THA
• Contraindication to or failed spinal anesthesia
• Allergy or contraindication to NSAIDs (e.g. chronic kidney disease)
• Diabetes requiring insulin medication
• Preoperative chronic use of illegal substances
• Renal insufficiency (eGFR < 60)
• Unstable psychiatric conditions
• Severe neurological disorder
• Cognitive deficiencies preventing informed consent
• Language barrier preventing completion of study
• Pregnancy or breastfeeding
• Chronic pain syndrome

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Ropivacaine; Patients receive spinal anesthesia with intrathecal ropivacaine	Drug: Spinal Anesthesia with Ropivacaine 15 mg (5 mg/ml); Patients receive spinal anesthesia with intrathecal ropivacaine
Active Comparator: Bupivacaine; Patients receive spinal anesthesia with intrathecal bupivacaine	Drug: Spinal Anesthesia with Bupivacaine 11 mg (5 mg/ml); Patients receive spinal anesthesia with intrathecal bupivacaine

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Return of Sensory and Motor Function	24 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Numeric Rating Scale (NRS) for Postoperative Pain	Pain intensity score assessed using the Numeric Rating Scale (NRS) for Pain (range 0 to 10, where 0 indicates no pain and 10 indicates worst possible pain; higher scores indicate worse pain outcomes).	24 hours
Urinary retention		24 hours
Post-operative nausea and vomiting		24 hours
Postoperative opioid consumption in morphine milligram equivalents (MME)		24 hours
5-Point Likert Satisfaction Scale	Patient satisfaction score assessed using the 5-Point Likert Satisfaction Scale (range 1 to 5, where 1 indicates very dissatisfied and 5 indicates very satisfied; higher scores indicate better satisfaction outcomes).	24 hours
Perioperative hemodynamics	Mean, systolic, and diastolic arterial pressure measured by non-invasive oscillometric monitoring and heart rate measured by continuous ECG/pulse oximetry at 10-minute intervals intraoperatively and in the PACU. Incidence of hypotension (MAP <65 mmHg) is also recorded. Units of measure: mmHg, beats per minute, and % of patients with hypotensive episodes.	24 hours
Onset time of block		24 hours
Adequacy of anesthesia	Sensory block level assessed by cold sensation testing (dermatomal level) at 10-minute intervals following spinal anesthesia, and incidence of requirement for supplemental sedation or analgesia recorded from anesthesia and PACU charts. Units of measure: dermatomal level (T-level) and % of patients requiring supplemental medication.	24 hours
Same day discharge rate		24 hours
Length of stay in the postoperative care unit and length of hospital stay		72 hours

Collaborators and Investigators

• Sponsor: University of Turku
• Collaborators: Turku University Hospital
• Investigators: Study Director: Panu Uusalo, MD, PhD, University of Turku and Turku University Hospital, Finland

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: May 7, 2026
• First Submitted That Met QC Criteria: June 2, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 2, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Hip; Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Anesthesia and Analgesia; Anesthesia, Conduction; Anesthesia; Ropivacaine; Bupivacaine; Anesthesia, Spinal
• Other Study ID Numbers: T2025/18111; 2025-522358-38-02 (Ctis)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data (IPD) will not be shared because the study data contain sensitive personal health information collected from a relatively small patient population at a single study center. Due to the limited sample size and detailed clinical information, there is a risk that participants could be indirectly identifiable even after de-identification. Data sharing is therefore restricted in order to protect participant privacy and confidentiality in accordance with applicable data protection legislation, institutional policies, and the informed consent provided by study participants.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No