Chronic wounds are wounds or ulcers that do not heal properly and are generally classified as venous, arterial, diabetic, traumatic and pressure chronic wounds and is often associated with inflammatory and neuropathic pain. Preliminary clinical studies have confirmed that injection of freshly prepared HA35 promoted the healing of chronic wounds and relieved the pain associated with chronic wounds. This clinical study is a prospective repeated experiments. The purpose of this study was to verify the effectiveness of HA35 injection therapy.

Our previous study, together with other studies, showed that topical use of the tissue-permeable HA fragment HA35 relieves swelling of the skin and mucosal wounds. In this study, the tissue-permeable 35 kDa HA fragment HA35 was freshly manufactured by mixing hyaluronidase PH20 injectable solution (H31022111) and high-molecular-weight HA injectable solution (H20174089). The therapeutic effect of the tissue-permeable HA fragment HA35 for the treatment of pain-associated chronic wounds was studied in a single-arm off-label study before and after treatment comparison.

Inclusion Criteria:

• The chronic wounds of painful diabetic wounds, venous wounds, arterial wounds, traumatic and pressure wounds whichvhad not been closed more than 3 months.
• All the chronic wounds were clinically presented by surface darkeness and purulent secretions on the wounds, and darkness or redness, swelling, dryness and broken surface of the skin immediately surrounding the wounds.
• Subject agrees to be compliant with study related visit and treatment schedule.
• Written informed consent.
• Adults aged 18-60 years.

Exclusion Criteria:

• Have a persistent pain resulted from other medical conditions or unknown causes.
• History of wound healing abnormalities or a medical condition that is known to be associated with abnormal wound healing.
• Subjects with any known coagulation disorder.
• Pregnant females.
• Be concomitantly participating in another clinical study.