Dexmedetomidine as an Adjunct to Periarticular Ropivacaine in Total Knee Replacement: A Pilot Randomised Controlled Trial

Not Applicable

Not yet recruiting

• Conditions: Postoperative Pain Management in Total Knee Arthroplasty
• Interventions: Drug: Ropivacaine + saline solution; Drug: Ropivacaine + Dexmedetomidine

• Registration Number: NCT07176065
• Lead Sponsor: University of Malaya

Brief Summary

This study aims to evaluate whether adding dexmedetomidine to ropivacaine-based periarticular infiltration (PAI) improves postoperative pain control in patients undergoing total knee replacement (TKR). Despite standard pain management, many patients continue to experience moderate-to-severe pain after surgery. Dexmedetomidine, a sedative and analgesic agent, may help prolong the effect of local anaesthetics. A total of 60 patients will be randomly assigned to receive either ropivacaine alone or ropivacaine with dexmedetomidine. Pain scores, opioid use, side effects, and recovery time will be monitored for 24 hours. The goal is to determine if this method is more effective and safer for improving recovery after knee surgery.

Detailed Description

Total knee replacement is associated with significant postoperative pain despite the use of multimodal analgesia. Periarticular infiltration (PAI) using local anaesthetics such as ropivacaine has become a common component of pain control protocols but offers a limited duration of relief. Dexmedetomidine, a selective α2-adrenergic agonist, has demonstrated analgesic benefits as an adjuvant in peripheral nerve blocks, but its role in PAI remains underexplored.

This double-blind randomised controlled trial will recruit 60 adult patients undergoing unilateral total knee replacement at Universiti Malaya Medical Centre. Patients will be randomly assigned to receive either PAI with 0.5% ropivacaine alone (control group) or ropivacaine combined with 100 µg dexmedetomidine (intervention group). All patients will receive spinal anaesthesia and an adductor canal block before surgery.

Pain scores will be recorded using the Numerical Rating Scale (NRS) at 1, 6, 12, and 24 hours postoperatively. Secondary outcomes include 24-hour opioid consumption (morphine milligram equivalents), patient satisfaction (5-point Likert scale), adverse effects (sedation, bradycardia, hypotension, PONV), and time to first ambulation. This study will provide important feasibility data and inform the design of a future multicentre trial, particularly within the Malaysian population.

Study Timeline

• Status Verified: 2025-05
• Study First Submitted: 2025-09-08
• Study First Submitted QC: 2025-09-08
• Last Update Submitted: 2025-09-08
• Study First Posted: 2025-09-16
• Last Update Posted: 2025-09-16
• Study Start: 2025-10-01
• Primary Completion: 2027-12
• Study Completion: 2028-12-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 60

Inclusion Criteria

• Aged ≥18 years
• Undergoing elective unilateral total knee replacement
• ASA physical status I-III
• No known allergy to local anaesthetics or dexmedetomidine
• No opioid use >24 hours preoperatively
• Provided informed consent

Exclusion Criteria

• Known allergy to study drugs
• Chronic pain or neurological conditions
• Bilateral or revision TKR
• Significant deformity affecting function
• Substance abuse history
• Day-case surgery

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Ropivacaine + Saline	Ropivacaine + saline solution	Patients will receive 20 mL of periarticular infiltration consisting of 19 mL of 0.5% ropivacaine and 1 mL of normal saline during total knee replacement.
Ropivacaine + Dexmedetomidine	Ropivacaine + Dexmedetomidine	Patients will receive 20 mL of periarticular infiltration consisting of 19 mL of 0.5% ropivacaine and 100 µg dexmedetomidine in 1 mL during total knee replacement.

Primary Outcome Measures

Name	Time	Method
24-hour postoperative pain score (NRS 0-10) at rest and during movement	24 hours postoperatively (from time of skin closure)	Pain intensity will be assessed using the Numerical Rating Scale (NRS), where 0 indicates no pain and 10 indicates worst possible pain. Measurements will be taken at rest and during passive knee flexion to 90°, at 1, 6, 12, and 24 hours postoperatively. The primary endpoint is the NRS score at 24 hours.

Secondary Outcome Measures

Name	Time	Method
Incidence of adverse effects (sedation, bradycardia, hypotension, PONV)	Within 24 hours postoperatively	Adverse effects will be monitored and recorded within 24 hours postoperatively: Sedation (RASS ≤ -2) Bradycardia (HR \< 50 bpm) Hypotension (MAP \< 65 mmHg or SBP \< 90 mmHg) PONV (score ≥1 on 0-4 scale)
Time to first ambulation	From end of surgery to first ambulation (within 24 hours)	Time from skin closure to the patient's first unsupported ambulation (\>5 metres) will be recorded in hours.
Total postoperative opioid consumption (MME)	24 hours postoperatively	Total opioid use in the first 24 hours postoperatively will be recorded from the PCA pump. All opioids will be converted into morphine milligram equivalents (MME) for standardisation.
Patient satisfaction with pain management	Postoperative day 1	Patient satisfaction will be measured on postoperative day 1 using a 5-point Likert scale, ranging from "very dissatisfied" to "very satisfied."

Trial Locations

Locations (1)

Universiti Malaya Medical Centre; 🇲🇾 Kuala Lumpur, Kuala Lumpur, Malaysia