Tissue Repair: How long does it take to heal from an injury?

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As a practicing physical therapist for the past 38 years, probably the most common question I receive is: how long before I heal, recover, or get better? This question is asked in many ways:

When will the pain stop? When can I do (insert favorite activity here)? And finally, one of the most difficult is, when will I get back to normal?

It’s always a tough question to answer because there’s so much variability based on the individual injury, the body part (or parts) involved, as well as how long the patient has been experiencing their pain. In this article, I will try to answer these questions in a general sense. We will discuss:

  1. How tissue heals in ideal conditions
  2. General factors that impact pain and healing
  3. General healing times of specific tissues and common injuries
  4. Considerations for assessing how long it takes injured tissue to heal

How tissue heals in ideal conditions (the stages of tissue repair)

Let me state right up front that there is never a perfect answer to this question. However, with certain acute injuries or post-surgical conditions, one can make an educated guess with some measure of medical certainty.

How tissue heals: There are four tissue repair steps, which occur in the following order:

  1. Hemostasis stage (stop the bleeding)
  2. Inflammatory stage (stop the infection)
  3. Proliferation stage (repair the tissue)
  4. Maturation stage (remodel the tissue into a mature form)

Homeostasis

Hemostasis literally means the stopping of a flow of blood. This is the first stage of healing. During this stage the injury site being closed by clotting. Hemostasis starts when blood leaks out of the body.

The first step of hemostasis is when blood vessels constrict to restrict the blood flow. Next, platelets stick together to seal the break in the wall of the blood vessel. Finally, coagulation occurs and reinforces the platelet plug with threads of fibrin (connective tissue). This begins to happen immediately.

The platelets adhere to the underlying cells surface within seconds of the rupture of a blood vessel’s wall. The connective tissue begins to form a mesh and to release other cells (prothrombin) to create a clot trapping the blood cells including platelets in the wound area.

Inflammation

Inflammation is the second stage of wound healing and begins right after the injury, concurrent with hemostasis. In this stage the injured blood vessels leak water, salt, and protein called transudate.

This leakage causes localized swelling. The inflammatory response both controls bleeding and prevents infection. The fluid engorgement allows healing and repair cells to move to the site of the wound. During the inflammatory phase, damaged cells, any microorganisms that cause infection called pathogens, and bacteria are removed from the wound area.

These white blood cells, growth factors, nutrients and enzymes create the swelling, heat, pain and redness is commonly seen during this stage of wound healing. Inflammation is a natural part of the wound healing process and is only problematic if it is prolonged or excessive.

Proliferation

Proliferation means “reproduction of a cell, part, or organism.” In this stage of tissue healing, the wound is rebuilt with new tissue made up of the building blocks of all connective tissue, collagen and additional cells called extracellular matrix.

In the proliferative phase, the wound contracts as new tissues are built. In addition, a new network of blood vessels must be constructed so that the tissue can be healthy and receive sufficient oxygen and nutrients.

Maturation

Maturation stage is often called the remodeling stage of wound healing and it is the final phase. The maturation stage is when collagen is remodeled or literally matured, and the wound fully closes.

The cells that had been used to repair the wound, but which are no longer needed are removed by a process of programmed cell death. When collagen is laid down during the proliferation stage, it is disorganized, and the wound is thick.

During the maturation phase, collagen is aligned along tension lines and water is reabsorbed so the collagen fibers can lie closer together and cross-link. Cross-linking of collagen reduces scar thickness and also makes the skin area of the wound stronger. Generally, remodeling begins about 21 days after an injury and can continue for a year or more.

A tens unit on a patient with a knee injury.

General factors that impact pain and healing

The stages of wound healing are a complex and fragile process. This process occurs irrespective of whether you suffer a strained ligament, surgery, or a laceration. Failure to progress in the stages of wound healing can lead to chronic pain and poorly/unhealed tissue. Factors that lead up to chronic wounds are cardiovascular diseases, venous insufficiency, infection, diabetes, and metabolic deficiencies (especially of the elderly).

Also, for healing of tissues that may be damaged because of injury there are other factors that will impact healing times, such as metabolic conditioning, severity of the injury, and external loading of the body part.

Careful injury care or wound care can speed up the stages of healing by avoiding excessive stress on damaged tissue, protecting an injured area from reinjury or infection and finally optimizing the metabolic environment for healing. Additionally, our preinjury health status plays a vital role in determining healing times.

Cardiovascular disease

Cardiovascular disease is a broad category of disease and may include peripheral arterial disease (occlusion or deceased flow of blood in the extremities), coronary artery diseases, occlusion or decreased flow of blood to the heart muscle itself), heart failure (a progressive disease where the hear cannot pump well enough to meet the body’s needs.), and other heart and vessel issues that can inhibit blood, oxygen, and nutrition in wound healing.

Each of these conditions and any other condition that might decrease the optimal circulation to tissue will delay or stop healing.

Venous insufficiency

Venous insufficiency is an abnormal health condition the impacts the veins and their function. There are many causes and ultimately leads to swelling pain and altered circulation.

Infection

The presence of infectious material in a wound will not allow the healing stages to progress sufficiently thus delaying or stopping the healing process. In the presence of an infection often the rate of tissue decay greatly exceeds the rate of tissue repair.

Diabetes

The long-term effects of diabetes may include damage to large and small blood vessels, which can lead to heart attack and stroke, and problems with the kidneys, eyes, feet, and nerves. With decreased sensation, one may not be sensitive to caring for or identifying the presence of a wound. Additionally, damage to blood vessels may inhibit optimal circulation to injured tissue.

Metabolic deficiencies

The metabolic process is the system your body uses to turn the food you eat into the energy it needs to keep all your systems functioning at optimal levels. Many factors may cause this system to become deficient. These include but are not limited to the following: Poor nutrition, environmental stressors, unhealthy lifestyle, poor processing of one’s food due to gut issues and or overall poor health.

As we grow older our tolerance to factors impacting our metabolism decreases and the need to maintain a healthy lifestyle and avoid that which is not.

Metabolic conditioning

One’s preinjury metabolic conditioning is an important factor. For a young healthy and fit individual with an acute injury to any of the tissues discussed in the previous chart, the estimated timelines are accurate. For your specific case please contact your physical therapist or primary care provider.

Severity of injury

More severe sprains, strains and fractures take more time to heal. Additionally, the volume of tissue involved may also be greater requiring more time.

External loading

Loading is an important factor for musculoskeletal injuries. Appropriate amounts of mechanical loading is needed for tissue regeneration. Too much mechanical force or overloading injured tissue may perpetuate the injury. An example of this is weight bearing with a lower extremity bone fracture.

At some point in the process of healing progressive weight bearing will be necessary. Excessive weight bearing just as in too little weight bearing will negatively impact the healing of the bone.

Movement mechanics play a role ion healing. Repetitive movement patterns or altered (compensatory) movement patterns may stress injured tissue, essentially overloading it, delaying the healing times. Finally, chronic inflammation may also become an issue in delaying healing times.

A patient with neck pain receiving manual therapy from a PT.

General healing times of specific tissues and common injuries

What follows are numerous examples of healing times for specific tissue under ideal circumstances.

For this discussion I will use typical tissues that may be damaged as part of a musculoskeletal injury. Please keep in mind that these ranges vary depending upon the severity of the injury. Tissue injuries are usually graded by severity:

Typical Tissue Healing Time Frames

Tissue types:Range of time for healing:
MuscleGrade I: 2-4 weeks Grade II: 8-16 week Grade III: 9-12 Months
TendonAcute: 2-6 weeks Sub-acute: 2-4 Months Chronic: 3-9 Months Surgical repair/Tear or rupture: 4-12 months
Bone6-12 weeks
LigamentsGrade I: 2-8 weeks Grade II:2-6 Months Grade III: 6-12 month ACL Graft: 12+ months
Cartilage9-24 months
NerveRegrowth rate: 3-4 mm/day

Considerations when assessing how long it takes injured tissue to heal

Now that we have reviewed the healing process and the estimated timelines for healing related to tissue type, let’s get back to the original question of how long it takes for an injury to heal. Whether your injury is a ligament in the knee, a disc injury in the neck/back, a laceration or a surgical incision, the stages of healing apply.

Knowing this, and taking into consideration the factors previously discussed, we can arrive at an educated guess as to how long it will take your injury to heal:

  • Is this an acute injury, such as a sudden sprain or strain that had a definite incident with observable tissue response?
  • Has this pain/injury been coming on slowly, such as with cumulative trauma to tissue even at low loads of can cause negative tissue changes and pain?
  • What movements/activities or positions make the condition worse?
  • What positions, movements or activities make the pain decrease?
  • What is your perceived intensity of the pain? (Keep in mind that pain is defined as “an emotional response to actual or potential tissue damage,” and one’s response varies depending upon life situations, experience with pain and expectations)
  • Is there disfiguration, swelling and or obvious bleeding/drainage.

Final thoughts

Lastly, I would discourage anyone from comparing one’s injury to your neighbor, friend or relative. I often get the comment, “Well, when my uncle had his surgery, he got better in 2 weeks.”

People’s recollection of their past healing experiences fades over time, so subjective reports are usually inaccurate. Additionally, everyone has a unique set of circumstances and those need to be considered when estimating healing times.

I hope this article helps you set good expectations for how long it will take you to heal from your pain or injury. If you have specific questions, or would like to set a consultation, please feel free to reach out to us.

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