63 patients with chronic infectious wounds were enrolled in the controlled study. They were randomly divided into three groups equally. Group 1 (Grp.1): The patients received hydrogel dressing change at three days intervals. Group 2 (Grp.2): The patients received ALA-PDT treatment at ten days intervals for 4 sessions. Groups 3 (Grp.3): The patients received ALA-PDT at ten days intervals for 4 sessions combined with hydrogel dressing change every three days intervals. The wound healing rate, total effective rate, patient satisfaction, adverse reaction, and recurrence were assessed in all groups.

Randomly divide the enrolled patients into three groups for treatment by utilizing SAS software (SAS Institute, Cary, NC, U.S.A.). Initially, the wound pus and secretions were washed three times with a sterile saline solution. Subsequently, surgical instruments were employed to debride the wound, particularly the necrotic tissue, as well as any carrion and foreign bodies within the wound bed and cavity, with care being taken to avoid injury to nerves and blood vessels in the surrounding area. Grp.1 was covered with hydrogel dressing (PAUL HARTMANN AG, Germany) and replaced 2-3 times a week with topical mupirocin ointment three times a day. Grp.2 received photodynamic therapy only. Grp.3 accepted PDT, then coated with hydrogel dressing as mentioned above. The treatment protocol of PDT is described as follows: after thorough debridement, ALA (Shanghai Fudan-Zhang jiang Bio-Pharmaceutical Co. Ltd, China) in an oil-in-water emulsion was smeared on the wound. After covering with dark plastic film for 3h, the wounds were illuminated by a light-emitting diode (LED) red light (Shenzhen Lifotronic Technology Co., Ltd, China). After the operation, a cold ice compress can be used to relieve the swelling and pain. Then, the hydrogel was uniformly applied to the wound and its surroundings (Grp.3). Grp.2 and Grp.3 received PDT at an interval of ten days for 4 sessions. In all groups, treatment responses and adverse reactions were recorded. All patients received the treatment as mentioned above and then evaluated the clinical outcome. After the end of the treatment, all patients returned for follow up at weeks 2, 4, 8 and 12.

Inclusion Criteria:

• 1) patients with chronic wounds caused by trauma or surgery who failed to heal after traditional formal medical treatment at least over three months;
• 2) Patients with stable vital signs who had no systemic medical disease and did not take glucocorticoids, immunosuppressive agents, or anticoagulants during the entire treatment process;
• 3) Participants provided signed informed consent, were able to comply with the program, were willing to participate in follow-up, and were able to cooperate in the observation of adverse events and efficacy;
• 4) The diameter of the skin wound should not exceed 10 centimeters.

Exclusion Criteria:

• 1) Patients are allergic to ALA;
• 2) Women with recent fertility, pregnancy or lactation plans;
• 3) Patients with deepening wounds or worsening infections;
• 4) Poor compliance leading to an inability to complete the treatment in its entirety;
• 5) Cutaneous ulcer caused by vascular disease, autoimmune diseases, metabolic diseases, local or metastatic malignant tumors.