Background: This study compared the Rescue analgesic requirement in ultrasound-guided 4-in-1 nerve blocks with Bupivacaine and Dexmedetomidine in two doses for knee and below-knee orthopaedic operations. Material & Methods: Patients who were scheduled for below-knee and knee procedures under SAB underwent a comparison study. 100 patients in all were divided into two groups at random. In a USG-guided 4 in 1 block, Group A received 29ml of 0.125% bupivacaine along with 0.5g/kg of dexmedetomidine to make a total 30ml solution, while Group B received 29 ml of 0.125% bupivacaine along with 1g/kg of dexmedetomidine to make a total 30ml solution. Results: In this study, time to first rescue analgesia in group A and group B was 579.12±62.43 min and 730.66±93.15 min respectively. Patients in group A required early intervention in terms of rescue analgesia. It was significantly longer in group B in comparison to group A (P = 0.0001). Duration of post-operative analgesia in group A and group B was 666.48±82.45 min and 801.96±92.97 min respectively. In this study, duration of analgesic effect was significantly longer in group B in comparison to group A (P = 0.0001). In this study, total rescue analgesic doses per patient were significantly more in group A in comparison to group B (P = 0.0001). In this study, total number of bolus doses of rescue analgesia was 123 in group A and 62 in group B which is almost double in group B in comparison to group A. Conclusion: Present study concluded that time to first rescue analgesia was significantly longer in group B in comparison to group A. Similarly, total rescue analgesic doses per patient were significantly more in group A in comparison to group B and Total bolus doses of rescue analgesia is almost double in group A as compared to group B.