Patients who agree to enter the trial will be divided at random to enter the different treatment arms of the study. The randomization schedule will be determined using an on-line random assignment sequence generator (www.graphpad.com/quickcalcs/randomize1.cfm) and will be kept and controlled by the study co-ordinator, and the surgeons will not have access to this schedule. The randomisation details for each patient will be written on to a slip of paper and placed inside an opaque envelope. Each envelope is attributed to one patient and given a study number. One of the research team will supply the operating theatre staff with one of the envelopes containing the slip of paper upon which will be written the randomisation allocation for the patient undergoing surgery at that time. The operating surgeon will not be allowed to open the envelope. The patient will be assigned the study number and their randomisation slip returned to the study coordinator to be kept with the Masterfile copy of the consent form. A hand written note will be made by one of the research team in the orthopaedic section of the patient's medical notes after their surgery, confirming that they consented to the study and detailing which arm of the study they were allocated to.