Granulation Tissue and Wound Healing: What You Should Know

What is granulation tissue?

When wounds are open and healing by secondary intention, full-thickness wounds of any etiology require granulation tissue to heal. Granulation tissue heals the wound by filling in the wound from the base, moving upward. Its formation requires a flurry of events at the cellular level.

How does it form?

The National Library of Medicine states that fibroblasts, keratinocytes, and endothelial cells form new granulation tissue.

Fibroblasts form the extracellular matrix, or ECM, vital to new tissue formation. This matrix is like a scaffold of protein, collagen, elastin, hyaluronic acid, and glycoprotein. It helps new cells grow, repair, and communicate. Fibroblasts also produce growth factors, helping to form new tissue.

Keratinocytes are important for cell to cell binding towards the end of proliferation. They produce signals and regulate cells.

Endothelial cells are responsible for angiogenesis that ultimately restores vascularization to the wound site. Without this important function, the tissue formation stops, and the wound-healing process stalls.

Why wounds need granulation tissue

Full-thickness wounds require the formation of scar tissue to heal. Granulation tissue fills the open spaces of full-thickness wounds, brings blood supply to the area, and helps protect against infection.

Full-thickness wounds can be quite significant. They may have areas of tunneling and undermining. New granulation tissue must fill this “dead space” for the wound to heal. Without granulation tissue, the wound remains open, leaving patients highly susceptible to infection, which can ultimately threaten both limbs and life.

Characteristics to consider

Healthy granulation tissue is red or pink and granular in appearance. The healthiest tissue is often described as having a “reddened ground beef” appearance or as resembling cobblestones.

The tissue will appear moist but should not have significant drainage. It should also be soft to the touch and may bleed easily due to new angiogenesis. Typically, granulation tissue isn’t particularly painful to normal touch and light cleansing.

What factors affect tissue quality?

When the texture appears pale or smooth, granulation tissue is considered to be less healthy than a more granular, red tissue. There are many reasons for poor quality, which include:

• Wound infection: This is the most common cause of poor-quality granulation tissue. In an infected wound, this tissue may bleed more easily and have a deeper, dusky color of red. Hypergranulation tissue also indicates a sign of infection.
• Presence of a foreign body: If a foreign body is present in a wound, this will regress the wound back into an inflammatory state. It will essentially stall the wound’s progress and increase the risk of infection.
• Inflammation during the proliferative phase: This will also stall a wound. Conditions that may regress a wound back to an inflammatory stage include diabetes, autoimmune disease, inappropriate wound care, and trauma to the wound, such as pressure, friction, and shearing. Address the cause of the inflammatory response to continue the healing process.
• Poor vascular status: This condition can cause suboptimal granulation tissue. Granulation tissue with poor blood flow will appear pale and often dry. Arterial studies may be warranted in wounds with poor-quality tissue and no healing progression. Abnormal studies should be referred to vascular surgery to assess for any necessary intervention.
• Hyperglycemia in uncontrolled diabetes affects the quality of the tissue by weakening the immune response, blocking cellular functioning, and obstructing angiogenesis. Collaborating with patients’ other care providers, including primary care or endocrinology, can help achieve better glycemic control and create a healthier healing environment.
• Poor nutrition affects the quality of granulation tissue. Wounds require specific amino acids, vitamins, and minerals to heal, and nutrition and hydration are essential in the proliferative phase of healing. Educating patients and caregivers on how to optimize meals and use supplements is an important part of the healing process.
• Medications (anti-inflammatories, biologics, anticoagulants, and steroids): These types of medications can slow or stop the healing process. They may interfere with the inflammatory phase, increase the risk of infection, and hinder tissue formation.
• Smoking and alcohol consumption: Both contribute to poor granulation tissue by affecting blood flow, increasing inflammation, and compromising new cell growth.

7 tips for maintaining optimal granulation tissue

As wound care clinicians, there are several practices we can implement and teach our patients to improve granulation tissue quality, including:

1. Choose an appropriate dressing that fills dead space without overpacking. Trauma to the wound walls can prevent new cell growth and damage fragile tissue (“fill, don’t pack”).
2. Select dressings that are skin-friendly, especially for older patients.
3. Teach proper removal of dressings to prevent wound trauma (low and slow).
4. Create a moist wound environment. Use products that both control drainage and prevent over-drying the wound bed. New cells will die in a desiccated wound.
5. Avoid using harsh wound cleansers, such as isopropyl, hydrogen peroxide, and Dakin’s solution. Consider cell-friendly hypochlorite solutions available at levels that provide benefits without damaging effects.
6. Serial debridement removes necrotic tissue and biofilm, creating a healthy wound environment and lowering infection risk.
7. Use dressings, durable medical equipment, and footwear to decrease pressure, shear, and friction to a wound. Constant trauma will prevent new tissue growth.

Often, the most difficult part of wound healing is getting out of the inflammatory phase and into the proliferative one. Once there, you’ll want to stay until the wound closes. With effective care of granulation tissue, you can continue the path of healthy healing and enhance the quality of life for your patients.