In the United States, an estimated 2% of the population is afflicted with chronic wounds. Due to aging and the presence of multiple comorbidities, the wound healing process does not undergo the four phases of healing promptly which results in a chronic wound. Chronic wounds represent a significant burden to the healthcare systems across the globe. The cost to Medicare for treatment of acute and chronic wounds ranged from $28.1 billion to $96.8 billion in 2014. In the UK, the treatment of chronic wounds represents an annual 5.5% cost to the NHS. Given the high prevalence and burden of chronic wounds, wound care specialists and podiatrists need to be able to recognize and identify the major types of chronic wounds.

Assessment Of Chronic Wounds

A thorough history and physical examination can help podiatrists and wound care specialists come up with an accurate diagnosis. Chronic wounds are generally classified based on etiology. The most common types of chronic wounds include venous ulcers, ischemic ulcers, diabetic ulcers, and pressure ulcers. Even though chronic wounds may differ based on etiology, they all share common features of increased levels of inflammatory cytokines, the presence of biofilms, and the presence of infections. Some of the points to be kept in mind for assessment of chronic wounds include:

• History: A thorough medical history is crucial in working out the diagnosis and further wound management. For instance, patients with diabetes mellitus are more likely to present with diabetic ulcers. Smoking is a risk factor for peripheral vascular disease and can lead to the development of ischemic ulcers. Special attention should be given to the onset, history of trauma, or presence of similar wounds in the past.

• Location: The location of chronic wounds can aid in diagnosis as certain types of chronic wounds are associated with particular locations. For instance, ischemic ulcers are more likely to occur in the distal extremities.

• Review of systems: The presence of an underlying medical condition like diabetes or chronic venous insufficiency can help clinicians to arrive at an accurate diagnosis.

Overview Of Chronic Wounds 

A summary of the features and diagnostic workup for common types of chronic wounds is given below:

Venous Ulcers

The location of the venous ulcers is typically diagnostic. Venous ulcers are usually located above the medial malleolus in the region known as the "gaiter area". They are shallow in appearance and present with typical signs of chronic venous insufficiency. Some of the associated signs include edema, lipodermatosclerosis or brownish discoloration of the skin, hemosiderin staining, and absence of eschar. Pulses should be palpation and ankle-brachial index should be measured to rule out arterial disease. Patients should be offered venous duplex ultrasonography to aid in diagnosis. 

Pressure Ulcers

Pressure ulcers result from a localized trauma to the skin, usually over bony prominences. Some of the common sites of pressure ulcers include the sacrum, hip, and heel. Screening tools like the Braden scale can help in the early identification of at-risk patients. Some of the important considerations in the management of pressure ulcers include nutritional assessment and support, CT scan or MRI to rule out the presence of deep tissue infection, and wound culture for the presence of infection.

Diabetic Ulcers

Patients with diabetes are at an increased risk of chronic wounds due to the impact of diabetes on wound healing. This is because of a combination of neuropathic and ischemic changes that lead to increased incidence of unnoticed trauma and impaired wound healing. Diabetic ulcers are most likely to be located on the pressure areas of the foot such as the toes and the plantar aspect. Diabetic ulcers could be either shallow or deep with exposure of the underlying tendons and bone. They are usually surrounded by a thick callus. Diagnostic workup should include an ankle-brachial index, measurement of glycosylated hemoglobin levels, and assessment of neuropathic changes using the monofilament. 

Arterial Ulcers 

Ischemic or arterial ulcers tend to be located on the distal extremities with a punched-out appearance. They are also typically very painful. As ischemic ulcers occur because of poor tissue perfusion, palpation of the lower limb pulses and measurement of the ankle-brachial index are of critical importance. Other diagnostic modalities that can be used for evaluation include duplex arterial ultrasonography, transcutaneous oximetry, and angiography to assess the patency of distal vessels.

Management Of Chronic Wounds

Even though there are differences in the specific management of chronic wounds depending on etiology, there are certain shared principles. This principle is referred to as the 'TIME' principle:

• Tissue Debridement: It is an essential component of wound care. Debridement helps to remove devitalized, necrotic tissue which helps to accelerate wound healing.

• Infection Control: Wound infection control is necessary for optimal wound healing. Infection can stall the wound healing process and contribute to complications.

• Moisture Balance: A moist wound environment is essential for optimal wound healing.

• Edges of the Wound: Rolled wound edges should be excised as it affects wound healing. Excision allows for more rapid wound epithelialization.

Specific management for the major types of chronic wounds are described below:

• Diabetic Ulcers: Special attention should be given to the control of blood sugar levels. Patients should be prescribed medicated shoes or offloading casts that relieve pressure from the affected part of the foot. Patients with thickened callus may also require surgical debridement.

• Arterial Ulcers: Patients with arterial ulcers may require surgical intervention to improve tissue perfusion. Some of the interventions include vascular bypass or stenting.

• Venous Ulcers:  Patients with venous ulcers benefit from the elevation of lower limbs and compression therapy. Endovenous ablation may also be required in certain scenarios for the management of venous insufficiency.

• Pressure Ulcers: Nutritional support should be given to the patients, and the patient's position should be changed every two hours. Cushions should be avoided for offloading as they can exacerbate the existing ulcers.