HOW WELL DO WE CONTROL ACUTE PAIN FOLLOWING TOTAL HIP REPLACEMENT

Background Hip arthroplasties are associated with high postoperative pain scores. In some reports, moderate to severe pain was 58% on the first day postoperatively in total hip replacements (THRs). Several techniques are currently used at our institution to tackle acute pain following THRs. These include: 1) Spinal anaesthetic (SA) with Diamorphine only; 2) General anaesthetic (GA) only; 3) SA with local infiltration anaesthetic mixture 1 (LIA1,). Mixture 1 consisted of ropivacaine, adrenaline, and ketorolac; 4) SA with LIA mixture 2 (LIA2). Mixture 2 consisted of bupivacaine and adrenaline; 5) SA with LIA1 and PainKwell pump system. In this study we report on the techniques of acute pain control following THR at our regional centre for elective primary THRs. Methods Between June 2011 and July 2014, 173 consecutive patients undergoing primary THR using the posterior approach were prospectively followed up. Group 1. GA only. 31 patients, Group 2. SA only. 37 patients, Group 3. SA plus LIA1 only. 38 patients, Group 4. SA plus LIA2 only, 34 patients, Group 5. SA plus LIA1 plus PainKwell Pump System for 48 hours. 33 patients. Results Fewer patients required opiate analgesia when LIA plus PainKwell pump system was used compared to the other groups. The highest significance was at 0–12 hrs for patients requiring up to 20mg morphine usage (χ2(2) = 46.713, p = 0.000); and 0–12hrs for patients requiring 30mg morphine usage (χ2(2) = 46.310, p = 0.000). There were no infections, DVTs or PEs in any group. One patient in group 3 suffered a stroke (ASA 4). A Kruskal-Wallis H test also showed that there was a statistically significant difference in morphine usage across groups 1, 2, 3, 4, and 5. Conclusion We recommend the use of LIA with PainKwell pump system continuous infusion as an efficacious method to control pain following THR.