Vecuronium will be used as NMB drug in all study patients; this agent is currently used in over 90% of THR cases at Maine Medical Center (MMC). As is currently routine Vecuronium will be given after initiation of general anesthesia with propofol to facilitate intubation and further doses of Vecuronium will be given throughout the case as noted below to maintain NMB at the desired depth until the femoral implant is reduced. After the intubating dose of Vecuronium, NMB depth will be monitored every 5 minutes and dosing will be adjusted as needed to maintain a constant depth of NMB according to our current routine practice.