Many methods of pain relief have been implemented in an attempt to provide safe and effective analgesia for patients following total knee arthroplasty. Numerous studies have demonstrated that nerve blocks can provide superior pain control and reduce side effects. There are two major nerves that provide sensation to the knee: the femoral nerve provides sensation to the front of the knee and sciatic nerve provides sensation to the back of the knee. Putting local anesthetic close to these nerves provides superior pain control. The literature has supported the use of femoral nerve block for analgesia as well as improved functional outcome after total knee arthroplasty. The purpose of this study is to see if the same is true for sciatic nerve block for the back of the knee. We also would like to study an alternative approach to make the back of the knee pain free. This involves injecting local anesthetic directly into this area at the end of your surgery.Patients will be randomized into 3 groups: sciatic block, posterior infiltration of local anesthetic and placebo.This study will help further define the role of sciatic nerve block as well as the alternative technique of local anesthetic infiltration in the perioperative analgesic regimen of total knee arthroplasty surgery, in an effort to develop a standardized perioperative protocol for this patient population. The advent of this protocol should allow reduced risk, improved analgesia, and potentially earlier discharged from hospital with better function.