Abstract
Background
Total knee arthroplasty is associated with early postoperative pain. Appropriate pain management is important to facilitate postoperative rehabilitation and positive functional outcomes. This study compares outcomes in TKA with three techniques; local infiltration analgesia, single shot femoral nerve block and intrathecal morphine.
Methods
Forty-five patients undergoing elective primary Total Knee Arthroplasty (TKA) with were randomized into one of three groups in a double blind proof of concept study. Study arm 1 received local infiltration analgesia ropivacaine intra-operatively, an elastomeric device of ropivacaine for 24 hours post-op. Study arm 2 received a femoral nerve block of ropivacaine with placebo local infiltration analgesia and placebo intrathecal morphine. Study arm 3 received intrathecal morphine, placebo femoral nerve block and placebo local infiltration analgesia. All patients received standardized pre-operative, intraoperative and Post-operative analgesic medication.
Participants were mobilized at 4 hrs, 24hrs and 48 hrs post operation. Range of Motion, Visual Analogue Scale (VAS) pain intensity scores and two minute walk test and Timed Up and Go test were performed. Postoperative use of analgesic drugs was recorded. Knee Society Score (KSS), Oxford Knee Score and Knee Injury and Osteoarthritis Outcome Score (KOOS) were completed at preoperative and 6 weeks post op.
Results
Assessment of the efficacy of analgesia will be conducted using VAS pain scores collected preoperatively, 0–24hrs and 24–48 hours postoperatively between the three randomized groups. Frequency of use of other analgesia and need for PCA will be compared between groups at 0–24hr and 24–48hrs post operatively. The assessment of functional outcomes will be measured between the three groups by comparing the ability to mobilize the first 4 hrs after surgery, maximal flexion and extension, two minute walk test and timed up-and-go preoperatively, on postoperative day 1 and 2 and 6 weeks. Patient reported outcome measures KSS, Oxford Knee score and KOOS will be compared for the three study arms.
Conclusion
Results from the study will provide important information for the management of TKA in the hospital setting. The comparison of the three commonly used analgesic techniques and mobilization outcomes are pertinent for physiotherapy and rehabilitation management, anaesthetic specialists, nursing staff, orthopaedic surgeons and patients.
