Comparing Two Regional Anesthesia Interventions for Knee Arthroplasty.

Osteoarthritis of the knee is a common disease of the elderly and knee arthroplasty is indicated in severe cases to improve long term pain and function. Along with perioperative quality analgesia, functional recovery is paramount in the postoperative period.Loco-regional techniques provide effective analgesia and can mitigate several side effects of systemic opioids administration. Also, adequate motor sparing analgesia( to prevent weakness of the thigh muscle) following total knee arthroplasty (TKA) is therefore paramount to ensure effective rehabilitation, early recovery, readiness to discharge or timely hospital discharge. There are several motor sparing regional technique described in literature. Adductor canal block (ACB), use of intrathecal ( IT) morphine and local infiltration by the surgeons (LIA) are such examples. Previous studies have shown the combination of ACB and IT morphine to be superior than LIA in providing analgesia. Posterior knee infiltration (IPACK), involves blocking the branches of the tibial nerve which provides sensory innervation for the posterior aspect of the knee. In combination with ACB, a motor sparing analgesic intervention is possible for knee arthroplasty. Rationale for doing the study is to evaluate 1. The effectiveness of IPACK block as a part of multimodal analgesic approach to knee arthroplasty surgery. 2. Enhanced recovery from superior motor sparing analgesia. 3. early hospital discharge We hypothesize that, following total knee arthroplasty surgery, the combination of continuous adductor canal catheter and I-PACK blocks will achieve a decrease in the time to readiness to hospital discharge as measured by the following four criteria: (1) adequate analgesia; (2) independence from intravenous opioids; (3) ability to independently stand, walk 3 m (metres), return, and sit down; and (4) independently ambulate 30 m without limitation of time. We postulate this will occur by providing superior motor-sparing analgesia compared