Pain following total knee arthroplasty (TKA) is associated with delayed recovery, impaired mobility, increased morbidity, longer hospital stay and greater cost. Adductor canal block has recently been shown to improve the pain control of patients following TKA. It is not known whether a single shot technique or a continuous catheter-based infusion technique provides optimal analgesia. The investigators hypothesize that a continuous technique would provide better analgesia and permit patients to achieve objective measures of recovery following TKA than a single shot technique.