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.
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 Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
60
0.5% ropivacaine (19 mL) + 1 mL normal saline administered intraoperatively via periarticular injection.
0.5% ropivacaine (19 mL) + dexmedetomidine 100 µg in 1 mL administered intraoperatively via periarticular injection.
Universiti Malaya Medical Centre
Kuala Lumpur, Kuala Lumpur, Malaysia
24-hour postoperative pain score (NRS 0-10) at rest and during movement
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.
Time frame: 24 hours postoperatively (from time of skin closure)
Total postoperative opioid consumption (MME)
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.
Time frame: 24 hours postoperatively
Patient satisfaction with pain management
Patient satisfaction will be measured on postoperative day 1 using a 5-point Likert scale, ranging from "very dissatisfied" to "very satisfied."
Time frame: Postoperative day 1
Incidence of adverse effects (sedation, bradycardia, hypotension, PONV)
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 frame: Within 24 hours postoperatively
Time to first ambulation
Time from skin closure to the patient's first unsupported ambulation (\>5 metres) will be recorded in hours.
Time frame: From end of surgery to first ambulation (within 24 hours)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.