Comparison of the analgesic effect of intra-articular and extra-articular injection of morphine and ketamine compound in arthrotomy lower limb surgery under spinal anesthesia

Objective: One of the critical components in the postoperative care is pain. Given that little research has been done regarding the analgesic effects of intra-articular injection of ketamine, this study was aimed to compare the analgesic effect of intra-articular and extra-articular injection of morphine and ketamine compound in arthrotomy surgery under spinal anesthesia. Methods: A total of 50 patients were candidate for arthrotomy surgery, aged 18-60 years were divided randomly into two groups. At the end of surgery, the first group was treated with combination of intra-articular morphine and ketamine compound and the second group was treated with combination of extra-articular morphine and ketamine compound. The amount of postoperative pain was recorded in the hours of 2,4,6,12,24 respectively. Also 24 hours consumption of rescue analgesic was recorded. Results: The pain severity (VAS) in the hours of 2, 4, 6, 12 and 24 after surgery in the intra-articular injection group was significantly lower than the extra-articular injection group (P<0.05). Postoperative morphine consumption in intra-articular injection group (3.2±3.78) was significantly less than the extra-articular injection group (6.36±5.22) (p = 0.018). Conclusion: Postoperative pain severity of intra-articular injection of ketamine and morphine in knee surgery is less than extra-articular injection.