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

University of Malaya

Status and phase: Not yet enrolling; Phase 4

Conditions: Postoperative Pain Management in Total Knee Arthroplasty

Treatments: Drug: Ropivacaine + saline solution; Drug: Ropivacaine + Dexmedetomidine

Study type: Interventional

Funder types: Other

Identifiers

NCT07176065

2025429-15014

Details and patient eligibility

About

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.

Full 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.

Enrollment: 60 estimated patients

Sex: All

Ages: 18 to 100 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Single Group Assignment

Masking: Triple Blind

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60 participants in 2 patient groups

Ropivacaine + Saline

Active Comparator group

Description:

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.

Treatment:

Drug: Ropivacaine + saline solution

Ropivacaine + Dexmedetomidine

Experimental group

Description:

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.

Treatment:

Drug: Ropivacaine + Dexmedetomidine