Participants may be discontinued from the study and assessments at any time. Criteria of premature withdrawal from trial include 1) Voluntary discontinuation by the participants without prejudice to further care; 2) Participants lost to follow up. For withdrawal from trial treatment: 1) Any surgical intervention to the wounds as required; 2) Safety reasons as judged by investigator; 3) Severe non compliance to the protocol as judged by the investigator, these patients will be followed to trial completion. Investigators should document the reasons for withdrawal in patient notes. The decision of withdrawal would not affect further wound care management.