*2.6. Safety Evaluation*

A series of evaluations were assessed to assure the safety of the study for 2 years after treatments. These evaluations included physicians' queries, physical examinations, laboratory tests, and radiological studies. The Common Terminology Criteria for Adverse Events was used to elicit and report toxic effects [47]. We specifically monitored the possible severe adverse events, including the severity of pain, infection of the operation site, joint adhesion, the abnormal gross appearance of the knee, active range of motion, loose body formation, and tumorigenesis.
