The human body is constructed from a variety of tissue types, each of which heals at a different rate and responds differently to various exercises or activities. It is important to know what type of tissue is compromised when injury occurs, in order to appropriately estimate a time frame for healing and to set appropriate expectations for rehabilitation. Listed below are the most commonly injured tissues that we deal with in physical therapy, along with a typical healing time frame for each. Considerations for rehabilitation for different tissue types are outlined thereafter. Please keep in mind that these are general guidelines. The body’s healing processes can be affected by a variety of factors related to each patient’s individual health history and life circumstances. Physical therapists will help each patient to make more personalized estimates for their own specific timeline for healing and rehabilitation, and will design each patient’s therapy treatment program to optimize this process.
Typical Tissue Healing Time Frames
|Tissue types:||Range of time for healing:|
Muscle Healing Considerations:
- Muscle has a rich blood supply, which is why it is the fastest healing tissue listed above. The circulatory system provides all tissues with nutrients and oxygen – both of which enable the tissue to heal. Because muscle gets lots of blood flow, it has a good environment for healing.
- Contracting and/or stretching muscles via a variety of specific targeted exercises stimulates blood to flow through the muscle tissue, encouraging health and healing.
- Injures can occur when muscle imbalances, are present. In these instances, some muscles are strong and tend to accomplish a disproportionate amount of work, at the same time as other muscles are weak and/or operate with poor motor control or efficiency. Often the strongest muscles are the ‘moving’ muscles, while the weak muscles are our stabilizing postural muscles. Postural muscles should be firing constantly to maintain appropriate posture and body position. If they stop firing correctly, the ‘moving muscles’ try to do their job. This will eventually lead to pain and injury – sometimes because the ‘moving muscles’ are overworked and begin to fail, and other times because the postural muscles’ failure to work creates a dysfunctional mechanical situation that stresses the skeletal structure. Correcting muscular imbalances via activities that promote proper movement and muscle recruitment patterns can allow muscle healing to occur.
Tendon Healing Considerations
- Tendons attach muscles to bones. Tendons generally have a more limited blood supply than muscles. This makes them somewhat slower healing structures in comparison to muscle.
- Blood supply to injured tendons can be stimulated by activities that cause tension on the tendon tissue. This could mean either tension that occurs when a muscle is contracted, or when it is stretched.
- Tendons tend to respond well to a particular type of tension. Eccentric activity, which means that a tendon is stressed while it is being lengthened, is particularly helpful for tendon remodeling after injury.
- One example of an eccentric exercise is performing a standing heel raise (pressing up onto your toes) and then slowly lowering your heels back to the ground. The deliberate, slow lowering towards the ground is eccentric exercise for the Achilles tendon
- Excessive tension on tendons while they are healing can cause increased pain, slowed healing, or sometimes even further injury. Physical therapists design tendon treatment programs with activities that provide gradual increases in tendon stress, so that the body can progressively adapt to high-intensity tendon activities such as those required in sports or heavy work.
Bone Healing Considerations
- Bones heal best when loads are applied to them. Weight bearing activities through injured bones stimulates an increase in bone growth at injury sites and a subsequent increase in bone strength. This concept is why immobilizer boots are often used in ankle and foot fractures rather than plaster casts. Allowing patients to walk while protecting their healing bone allows the bony repair process to occur faster and more thoroughly than keeping weight entirely off of a fracture site.
- After a fracture, even if a patient is allowed to bear weight, the injured bone should be immobilized so that the healing process can occur. Allowing too much movement at a fracture site too early in the healing process can lead to delays in fracture repair.
- Initial rehabilitation after a bone fracture often focuses on normalizing body movement in regions around the fracture site. Promoting general circulation through aerobic activity and strength training in other body parts can help with the bone healing process. As a fracture knits and becomes sufficiently stable, rehabilitation activity is focused more on the body part that has been fractured.
Ligament Healing Considerations
- Ligaments attach bones to other bones. They generally have a more limited blood supply than either muscle or tendon – lengthening their healing time.
- Ankle sprains and ligamentous tears in the knee (such as an Anterior Cruciate Ligament injury) are two common ligament injuries.
- There are 3 grades of ligament sprain. Grades are based on the amount of disruption involved to the ligament in an injury, and are defined as follows:
|Grade 1||Grade 2||Grade 3|
|· Mild sprain
· No swelling, and small hemorrhage (bruising)
|· Moderate sprain
· Small tear
· Significant amount of swelling
|· Complete tear
· Low stability (unstable)
· Requires surgery to repair
- For any type of ligament injury, protecting the injury site is important while the tissue is healing. At the same time, motion at the injured joint is desired, to promote circulation so that healing occurs. In order to allow motion while protecting ligament, some sort of bracing is often utilized. Physical therapists also design ligament treatment programs so that the movements made during therapy activities protect the healing tissue.
- The rehabilitation process after a ligament sprain may be accelerated or slowed depending on the grade of the ligament injury. Treatment program design after ligament injury is individualized and also modified depending on each patient’s response to every stage of post-injury care.
Cartilage Healing Considerations
- Cartilage is avascular, meaning that it has no blood supply. The lack of blood circulation in cartilage means that it is a very slow-healing type of tissue. Nutrition to cartilage is maintained by fluid in the joints, which lubricates the tissue. The lubrication process occurs by a sort of flushing mechanism, when load is applied and then removed from the tissue repeatedly. Activities such as stationary cycling and walking that involve repeated smooth joint movement can promote this lubrication process without creating too much stress on injured cartilage tissue.
- Cartilage is also aneural – meaning that it has no nerve supply. Because of the lack of nerve endings, pain is generally not felt when cartilage is damaged until it has been worn down significantly. Pain is felt when faulty movement at the injury site has started to impact another tissue in the area, such as underlying bone or associated ligamentous tissue.
- Inactivity has negative effects on joint cartilage. Lack of movement or of weight bearing can cause thinning of cartilage, making it susceptible to injury. Therefore – even fairly immediately after injury – exercises that encourage joints to move throughout their range of motion and that involve some degree of load bearing through the joint surfaces help cartilage to heal. Increased stresses to healing cartilage tissue then need to proceed in a very gradual pattern to protect the slowly healing tissue.
Nerve Healing Considerations
- Nerves conduct signals from your brain to your muscles, allowing movement. Nerves also conduct messages towards the brain, relaying information from muscles, skin, and joints about temperature, pressure, pain, body position, and body movement. Some nerves are quite long – extending for instance from the base of the spinal cord all the way down to your toes.
- There are multiple areas in the body where nerves can become entrapped or pinched when an injury occurs. Over-stretching a nerve can also cause it to be injured. An injured nerve can cause pain as well as other symptoms such as numbness, tingling, or muscle weakness. Sometimes nerve tissue is injured only in a small region. Other times, the effects of an injury can cause problems along the entire length of the nerve.
- After a nerve is injured, it is important to improve the mobility of the nerve and of the other soft tissues around the nerve, to relieve pain and also restore a nerve’s normal ability to glide in relation to the tissues surrounding it. Normalizing nerve mobility can also improve the conduction of messages sent both towards and away from the brain.
- Too much stress on a healing nerve can cause increased pain and nerve reactivity. Rehabilitation activities targeted towards nerve tissue need to be prescribed carefully – often in short intervals initially.
- Nerve healing proceeds at a very slow rate, and can be interrupted by repeated overstress. Stimulating nerve repair is a process that requires patience and persistence. However, it is possible to design treatment and exercise programs that allow patients to participate progressively in normal activities while also continuing to promote the health of the healing nerve tissue.
It is worthwhile to note that typically, more than one type of body tissue is involved when the body is affected by injury and/or illness. The most effective physical therapy treatment and rehabilitation progression will include activities designed to affect each type of involved tissue. The design of an appropriate treatment program needs to take into account the relative priorities of a body that is healing, and needs to be continuously modified as the healing process occurs so that each tissue that is healing is provided with its optimal healing stimulus at any given time. The same activities that are appropriate initially after an injury are seldom the most appropriate activities to continue with as the healing process evolves.
It is not uncommon for physical therapists to hear that their patients were sent home after initial medical consult post-injury with a written sheet of activities that they were told to work on at home. This was probably (hopefully) a good starting point. However, it was also a very generic, one-size-fits-most place to begin rehabilitation. Regardless of how simple or complex recovery is anticipated to be in any given situation, a physical therapist working as a team with each patient will be able to provide additional effective care during the entire course of a rehabilitation process. Sometimes this might involve only several visits over the course of time. Other times more intensive or frequent care might be indicated. The therapists at Symmetry recommend consulting with your physical therapist any time that mobility and daily function are negatively impacted by pain or injury. Getting started on an appropriate program of rehabilitation can considerably speed the process of recovery and minimize activity limitations – allowing maintenance of optimal musculoskeletal health.