Regarding analgesic techniques used in total knee replacement (TKR), which you consider the most appropriate:
A)    Continuous epidural block
B)    Single shot femoral, sciatic and obturator nerve blocks
C)    Continuous femoral nerve block with obturator and sciatic single shot blocks
D)    Continuous lumbar plexus block with sciatic single shot block
E)    Subarachnoid block with intrathecal morphine
Despite the successful analgesia of neuroaxial blocks, they are invariably associated with a bilateral block, retarding the patient mobilization, besides the precautions with catheters in patients receiving thromboprophylaxis. The intrathecal morphine appears to be helpful, however their potential side effects may limit its use.
The continuous peripheral nerve/plexus blocks produces a more effective analgesia, when compared with single shot techniques.
The continuous lumbar plexus block (with sciatic nerve block), although effective, it is a profound block, which requires an experienced operator, due to risk of inadvertent puncture.
Lastly, the continuous femoral nerve block, especially when associated with sciatic and obturator nerve blocks, it is a technique with fewer risks, which results in an effective analgesia, decreased opioid consumption and postoperative early mobilization.