Study of Peri-Articular Anaesthetic for Replacement of the Knee

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