Application of Chitosan and Chondroitin Sulphate Aerogels in a Patient With Diabetes With an Open Forefoot Transmetatarsal Amputation

Alejandra Vidal, MD; Annesi Giacaman, PhD; Sandra L. Orellana, PhD; Sandra Jofré, RN; Ignacio Moreno-Villoslada, PhD; Felipe Oyarzún-Ampuero, PhD; Miguel Concha, PhD


Wounds. 2020;32(3):E14-E18. 

In This Article

Abstract and Introduction


Introduction: Diabetic foot ulcers may lead to nontraumatic amputations of the foot, leading to a decrease in patient quality of life. Transmetatarsal amputations (TMAs) represent an effective surgical procedure in cases of severe foot infection, but the tissue reconstruction is complicated and additional procedures should be considered. The present case report evaluates the wound closure of an open TMA in a patient with diabetes treated with a new aerogel composed of chitosan (ChS) and chondroitin sulphate (CS), without needing a skin graft.

Case Report: A 72-year-old man with diabetes and a history of successive amputations was admitted to a hospital in Valdivia, Chile, due to a severe infection of toes 2 and 4 of the right foot. After the diagnosis of gangrene and osteomyelitis, the patient underwent a TMA of his right forefoot. The surgeon proposed the incorporation of ChS and CS aerogels to accelerate wound healing to avoid another surgical procedure. The TMA surgical wound area closed 50% after day 28 from starting treatment with aerogels. Complete closure was achieved at day 94 of treatment with aerogels, with good epithelial tissue and favorable cosmetic results and without residual limb deformities. The patient experienced minimal physical and psychological impairment from the procedure. Other surgical procedures were not necessary.

Conclusions: Due to the results of this patient, use of ChS and CS aerogels could represent an alternative treatment for forefoot TMA wound closure and prevent further surgical procedures, such as skin grafting. Future works should consider a larger number of cases.


Diabetic foot ulcers (DFUs) are a complication of diabetes mellitus that may lead to nontraumatic amputations of the foot, with a negative impact on patient quality of life and economic burden.[1,2] Tissue reconstruction in patients with foot amputations is complicated. Good surgical handling of soft tissue should be considered, with the goal of maintaining a functional and plantigrade limb with good cosmetic and functional results. However, wound healing is frequently a major challenge. Hence, alternative procedures and new wound healing materials should be considered for this type of wound.[1–3]

Transmetatarsal amputations (TMAs) represent an effective surgical procedure in cases of severe forefoot infection and gangrene. Despite their low healing rate, if there is gangrene involving more than 2 toes, a TMA is considered by many surgeons to be the operation of choice.[2] It preserves foot function and is cosmetically favorable.[2,3] Patients with a healed TMA have good mobility and independent ambulation.[4]

All amputations require meticulous preoperative and postoperative management in order to prevent frequent wound healing failure and reduce the high economic cost due to prolonged hospitalization, rehabilitation, and home care.[2] Thus, efforts to guarantee the best treatment that ensures wound healing are warranted.[5] Reconstructive techniques such as skin grafting could be used after forefoot TMA, permitting a fast covering, preventing infections, and providing psychological relief for these patients;[6] however, some patients can experience anxiety and mood changes after a skin graft.[7] Sometimes skin grafting requires an extensive period of wound bed preparation, which in some cases can be up to 40 days.[6] Donor site wounds also require care during the postoperative period, and some drawbacks include scarring and poor cosmetic outcome.[8]

The authors have previously reported the development of a new investigational material composed of chitosan (ChS) and chondroitin sulphate (CS) aerogels.[9] Chitosan is a natural polymer widely used in the biomedical field, is biocompatible and biodegradable, and has antimicrobial effects.[10] In combination with the glycosaminoglycan (GAG) of the extracellular matrix (ECM), such as CS, hyaluronic acid, and dermatan sulfate, it can form sponges and scaffold for diverse applications in tissue engineering, chronic wound healing, and drug delivery.[11]

The aerogel used here is cell-free, developed in an aqueous medium, and uses a low concentration of reagents in their composition. This aerogel was designed as a skin wound healing agent with the goal to minimize the amount of matter applied to wounds.[9] The lower density of the materials allows for better control of the individual polymer components of ChS and CS and presents better biological properties for several applications and minor metabolic stress in the damaged tissue.[12] In addition, the molecular assembling of this material based in electrostatic forces avoids the use of cross-linkers frequently related with toxic and allergic reactions.[13] Diverse nanoformulations have shown potential therapeutic effects on wound healing and allow achieving a better control of the dosage.[14] Aerogels synthesized under these criteria are biocompatible and provide specific properties for the induction of wound healing, do not affect the metabolic activity of cultured cells, and in experimental animal models, open wounds close significantly faster, unlike control wounds.[15] The ability demonstrated by ChS and CS aerogels to induce wound closure also was observed by the authors in a preliminary study of 3 patients with diabetes who had undergone amputation of one of their toes.[16]

The present case reports the wound closure of an open TMA in a patient with diabetes who was treated with ChS and CS aerogels and did not need additional surgical procedures.