 This study is to isolate and expand MSCsRegStem from infrapatellar fat pad of subject. When the number of MSCs expands to 1×108, cell will be cryopreserved in the liquid nitrogen tank until all release tests passed. On the distribution day, cell will be thawed and injected into joint cavity of patient 5×107. Subjects will be monitored after MSC product infusion of seven days, one month, six months and one year. The monitoring items include the changes of knee by appearance, X-ray and MRI of knee and pain improvement by questionnaire. 