Randomised control trial of adductor canal block versus intra-articular catheter in knee replacement surgery

INTERVENTION: Adductor canal block versus intra‐articular catheter for pain relief in total knee replacement surgery. (Both treatments are given in addition to standard anaesthetic care) Group Adductor canal block Ultrasound guided injection into adductor canal to administer block of femoral nerve at this level of 20ml 0.375% ropivacaine with 8mg dexamethasone. Administered once only immediately prior to surgery. CONDITION: Knee osteoarthritis PRIMARY OUTCOME: ‐ a clinically and statistically significant difference in range of movement of the operated knee measured by goniometer in degrees. ; The primary endpoints are ; ‐a clinically and statistically significant difference in pain as measured by a visual analogue scale ; SECONDARY OUTCOME: ‐ a clinically and statistically significant difference in scores on the Oxford knee score ; ‐Use of breakthrough analgesia as measured by doses of patient controlled analgesia administered / use of PRN analgesia. INCLUSION CRITERIA: Undergoing Total knee replacement Able to consent to inclusion in study