Perioperative protocol and discharge criteria Pre-operative digital templating was performed by the senior with AGFA IMPAX Orthopaedic Tools (Agfa Healthcare, Mortsel, Belgium) for every patient. Multimodal analgesia protocol including preoperative, intraoperative and postoperative medications (pregabalin, tramadol, acetaminophen, and celecoxib) was used in every patient. Intra-operatively, the patients received local infiltration analgesia with periarticular injection of diluted ketorolac and levobupivacaine solution. Additional intramuscular morphine was given for pain relief. The discharge criteria included (1) ambulation for 30 meters with assistive devices, (2) the ability to go up and down stairs with assistive devices, and (3) no need for intravenous or intramuscular analgesics.