Patient Controlled Epidural Analgesia Versus Local Infiltration Analgesia Following Knee Arthroplasty

Patient Controlled Epidural Analgesia Versus Local Infiltration Analgesia Following Knee Arthroplasty

Patient Controlled Epidural Analgesia Versus Local Infiltration Analgesia Following Knee Arthroplasty Within an Enhanced Recovery Programme - a Randomised Controlled Trial

The purpose of this study was to determine if the method of peri-operative analgesia used following total Knee Replacement surgery affected the progress towards rehabilitation goals and to determine whether the analgesia had any impact on long term outcomes.

Enhanced Recovery Programmes (ERP) as defined by Henrik Kehlet have been established within orthopaedics within the United Kingdom in a number of centres (Malviya et al., 2011, McDonald et al., 2012, Scott et al., 2013) demonstrating improvements in patient outcomes. However as the ERP involved in all of these papers are a redesign of a number of key elements of the clinical pathway it remains unclear as to the level of significance each component may have on the patient's reported outcomes. The use of Local Infiltration Analgesia (LIA) as the primary post-operative analgesic technique has grown in popularity in Scotland over the past 5 years (Scott et al., 2013). A number of large cohort series have concurrently reported significant improvements in early ambulation and shortened lengths of stay (Malviya et al., 2011, McDonald et al., 2012) yet it remains unclear as to whether this is due to the introduction and use of the LIA technique or the overall development of the ERP programmes. The aim of this parallel group randomised controlled trial was to test two different methods of regional analgesia (LIA and Epidural) and their impact on attainment of predetermined rehabilitation criteria for direct discharge home and to consider the impact of each technique on long term functional status up to one year post surgery. Epidural analgesia when utilised as post-operative analgesia is predominantly used in the format of a continuous infusion of a set volume of analgesia (+/- adjuncts such as fentanyl) resulting in both a motor and sensory blockade, which as would be expected increases with the volume infused. Ambulatory patient epidurals have been used for a number of years within maternity services which provide adequate pain relief whilst enabling the patient to be mobile (Stewart & Fernando, 2011). Therefore to provide a fairer comparison with the LIA technique the standard epidural analgesia technique within the Golden Jubilee National Hospital was adapted to a Patient Controlled Epidural Analgesia (PCEA) system with no background infusion. The planned long term follow up period ( One year) was developed to enable greater evidence of the impact of each method on functional capacity, Patient Reported Outcome Scores (PROMS) and to monitor the incidence of adverse incidents over a longer period of time than previously published literature.

A lumbar epidural was sited using a side-directed technique towards the side of surgery following establishment of the spinal blockade. Following the completion of the operation, patients received 4ml of 0.25% levobupivacaine prior to leaving the operating room. Thereafter they were connected to a PCEA pump (McKinley 545) with no background infusion. Patients could self-medicate with a bolus 2ml of 0.125% bupivacaine via the PCEA system with a lockout time of 15 minutes to control their pain until the following morning (post-operative day one) when it was stopped. Nurse-administered rescue top-ups of 4ml of 0.25% levobupivacaine were available for insufficient analgesia. The epidural catheter was removed on the morning of post-operative day two (POD2).

Subcutaneous infiltration during surgery using 200ml of 0.2% plain ropivacaine. 50ml injected following bone preparation prior to implant cementation perpendicular to the posterior femur through the posterior joint capsule in 10ml aliquots. 30ml proximal to the suprapatellar pouch down to the femur.100ml spread into subcutaneous tissues including; collateral and cruciate ligaments, fatty and connective tissue on the anterior aspect of the incision. A 16 gauge epidural catheter inserted via a medial portal, 20ml was injected via the catheter following closure of wound. Post-operatively, patients received boluses of 40ml ropivacaine 0.2% via the catheter using a mechanical McKinley 595 pump 4 hours after leaving theatre, at 22:00 and 08:00 on post-operative day one.

Following the operation, 4ml of 0.25% levobupivacaine was administered and the catheter was connected to a PCEA. Self-medication with a bolus 2ml of 0.125% bupivacaine via the PCEA system with a lockout time of 15 minutes until the following morning (post-operative day one) when it was stopped.

% of patients meeting predetermined discharge criteria at 96 Hours post-surgery. The discharge criteria were: self dependent (dress, personal care); in and out of bedd independently; up and down stairs; walk with crutches/stick; 80 degrees knee flexion; able to straight leg raise operated limb.

Summary 24 hour Verbal rated numerical pain scores were gathered each day. Scale range 0-10 where 0 is no pain and 10 is worst imaginable pain

percentage of patients reporting either symptoms of nausea or vomiting over the first 72 hours following surgery. Scale 0-2 wherein 0=no nausea and vomiting, 1=nausea and 2= nausea and vomiting

Units measured on old Oxford Score (12-60) from a 12 point questionnaire. Where in 60 is poor and lower scores are better patient reported outcome scores

Inclusion Criteria: All patients (age> 18years old) undergoing primary unilateral total knee arthroplasty (TKA) with a clinical diagnosis of osteoarthritis Exclusion Criteria: Patients planned for uni-compartmental/bilateral or revision knee surgery patients Patients with a diagnosis of rheumatoid arthritis (RA) Patients with coagulation or anatomical defects e.g. preventing the use of spinal anaesthesia Known allergies to any medications within the trial Patients who were unable to give written informed consent Patients requiring pre-operative catheterisation for urinary outflow dysfunction Known neurological incident that would limit or make impossible early ambulation following surgery