Patient Controlled Epidural Analgesia Versus Local Infiltration Analgesia Following Knee Arthroplasty

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.

Eligibility Criteria:
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