Eligible patients undergoing unilateral TKA under spinal anesthesia consenting to a multimodal analgesic regimen inclusive of ITM, FNB, and SNB will be recruited. All patients will receive spinal with intrathecal morphine. Patients will be randomly assigned using a computer generated table of random numbers to receive either spinal with intrathecal morphine (morphine group), a combination of intrathecal morphine and femoral nerve block (morphine-femoral group), or a combination of intrathecal morphine and femoral nerve block as well as sciatic nerve block (morphine-femoral-sciatic group).