Abstract
Background
Acute pain following total knee replacements (TKRs) is associated with higher peri-operative opiate requirements and their side effects, longer hospital stay and lower patient satisfaction (Petersen 2014). It may also be associated with higher rates of chronic pain at 1 and 5 years (Beswick 2012). We present a novel technique using combination of Local Infiltration Anaesthesia (LIA) with PainKwell infusion system (Bupivacaine 0.5 @ 4mls and 6mls/hr) to improve pain management following TKRs.
Methods
Between October 2015 and March 2016. 110 patients undergoing primary TKR were prospectively studied. All patients studied had spinal anaesthesia (SA) with diamorphine. Demographics between the two groups were similar.
Group 1. SA plus LIA plus traditional multimodal analgesia. 32 patients.
Group 2. SA plus LIA plus PainKwell for 48 hours rate 4mls. 38 patients
Group 3. SA plus LIA plus PainKwell for 48 hours rate 6mls. 40 patients
Results
Visual analogue pain scores demonstrated a significant difference at 8hrs, 12hrs, 24hrs and 48hrs between group 1 and 3; p<0.05. There was also a statistical difference in opiate usage at 24 hours between the three groups with group 3 using significantly less opiates compared to group 1. There was least consumption of opiates in group 3 patients across all study periods.
Conclusions
This study reported that SA plus LIA and PainKwell system was effective in reducing pain following TKRs. It also demonstrated that the technique of SA plus LIA plus PainKwell for 48 hours at a rate 6mls/hr reduced opiate usage by 50% and pain by 30% for these patients.
Implications
This technique may help improve rehabilitation and shorten hospital stay following total knee arthroplasties.
