Study of Peri-Articular Anaesthetic for Replacement of the Knee

The trial design is a patient-blinded multi-centre, active comparator, randomised controlled two-arm parallel group superiority trial of liposomal bupivacaine plus bupivacaine hydrochloride versus bupivacaine alone for post-operative pain in patients undergoing knee replacement surgery.

Patients will be randomised in a 1:1 ratio. The randomised controlled trial (RCT) design is robust and reduces any potential bias. Patients will be blinded as to which treatment they receive. Blinding of patients is possible as they will be under general anaesthetic for their knee replacement surgery at the time of the drug administration. Blinding of surgeons, who administer the medication and outcome assessors was not necessary as the primary outcome is a patient reported outcome measure.

Inclusion criteria

• Unilateral primary knee replacement, including both total knee replacement (TKR) or unicompartmental knee replacement (UKR), for end stage osteoarthritis
• American Society of Anaesthesiologists (ASA) Grade I to III
• Participant is willing and able consent for themselves
• Male or Female, aged 18 years or above
• In the Investigator's opinion, is able and willing to comply with all trial requirements

Exclusion criteria

• Allergy or intolerance to amide type local anaesthetics
• Objective evidence of nerve damage in the affected lower limb.
• Rheumatoid arthritis
• Any other significant disease, disorder or condition which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the results of the trial, or the participant's ability to participate in the trial.
• Participants who have participated in another research trial involving an investigational product in the past 6 months.
• Participants who have significant cognitive impairment or language issues
• Contra-lateral knee replacement within the trial or within 12 months prior to randomisation