Comparison of ultrasound-guided genicular block vs. intrathecal morphine for postoperative analgesia in patients undergoing knee arthroplasty: A randomised prospective study

Aim: Total knee arthroplasty (TKA) is a major orthopedic surgical procedure often necessitating effective postoperative analgesia. This study aimed to compare the analgesic efficacy of ultrasound-guided genicular block (GB) and intrathecal morphine (ITM) in patients undergoing THA under spinal anesthesia.Method: A prospective, randomized, single-blind study was conducted at Ordu University Training and Research Hospital from October 1, 2022, to April 1, 2023. Eligible patients aged 18 to 90 undergoing knee surgery with spinal anesthesia were randomized into two groups: Group ITM received intrathecal morphine, while Group GB underwent ultrasound-guided triple genicular block. Pain scores, rescue opioid consumption, time to initial mobilization, and Modified Bromage Scale (MBS) scores were assessed at five time points (0, 2, 6, 12, and 24 hours) within the first 24 hours post-surgery.Results: At the 24-hour mark, cumulative tramadol consumption was significantly lower in Group ITM compared to Group GB (35.45±54.84 vs. 63.37±37.7 mg, respectively, p = 0.028). Group ITM also exhibited statistically lower Numeric Rating Scale (NRS) scores at 12 hours (p = 0.005) but had similar scores at other time points. Additionally, time to first ambulation and MBS scores were consistent across all intervals (p < 0.05).Conclusions: In patients undergoing knee arthroplasty with spinal anesthesia, those receiving ultrasound-guided genicular blocks demonstrated higher opioid consumption over a 24-hour period compared to those receiving intrathecal morphine. However, regarding postoperative pain scores, both groups exhibited similar outcomes. These findings provide valuable insights into the selection of postoperative analgesic modalities for TKA patients.