Wound or Injury Healing - An MSK Therapy perspective
As remarkable as the human body is, there has always been a constant need to manage limited resources. Bodily functions and processes all utilise varying levels and types of resources including energy, nutrients, vitamins, minerals, water etc. Historically, gaining access to such resources and in, sufficient quantities could have proved difficult and still is in some parts of the world. As a result, the body has developed various strategies to manage these scarce resources as efficiently as possible. Such approaches are visible in our decision-making processes, the human stress response (see article) and tissue healing. Studies have shown that there is a general preference for emotive decision making, which uses up far fewer resources than higher brain function decision making. The consequences of a poor decision tend not to have life and death implications for the vast majority of society. Within the military environment, even seemingly insignificant decisions can have life and death ramifications. Hence, selection and training processes within the military and emergency services are designed to produce fact-based decision making rather than emotional.
Healing vs Regeneration
The human body has also opted to heal tissues, rather than regenerate tissues, though there are notable exceptions such as the liver. Healing vs regeneration is far more efficient in terms of resource usage though there are tradeoffs. Regenerated tissues would be as good if not identical to the original tissues before an injury in terms of look, function etc. Healed tissues (scar tissue), on the other hand, physically looks different from the original tissues and is not functionally as good. That said, the human survival strategy of healing over regeneration has worked well, and humans have flourished. Some animals have notably opted for regenerating as a survival strategy and can regrow tails (the Gecko image), ears or other limbs.
Adaptions to trauma (wounding)
Trauma or wounding to the body not only creates physiological changes to injured tissues and structures but also leads to adaptive changes. Adaptive changes will occur at the time of wounding, during the injury healing phases and even post-injury. The human body tends to try to avoid pain at the time of injury. One will usually try protecting the injured tissues and prevent painful movements and instead opt for a position(s) of comfort. Throughout the healing process, the body will adapt to how one moves to prevent further irritation to wounded tissues. Once, an injury has fully healed the affected tissues will never be quite the same as the original tissues, which can lead to further adaptions. On a subconscious level, the body is continually learning, and that includes how we move. Pain avoidance movement patterns created at the time of injury, during healing and post-injury become learnt as "normal". Such acquired patterns and adaptions result in changes to tensile forces, both tensional and compressive within the body or biotensegrity (see article). Although physical movement adaptions can prove helpful with tissue healing, they may also lead to chronic pain in some cases.
The healing process
The healing process involves several stages three to four, depending on if one chooses to group the first and second phases. Many aspects of the steps overlap, and the duration of each period can vary to some degree dependant on variables. Variables might include, the severity of the initial injury, the supply of necessary resources while healing (nutrients, fluids etc.), the type of tissues injured (vascularity), adequate rest, prevention of further injury while healing, other medical conditions, etc. Prolonged and repeated interruption of the bodies healing process and causing further damage can easily lead to chronic pain.
Homeostasis (Bleeding) Phase
When an injury occurs to tissues, the first reaction of the body is to bleed, which in some respects can help clean flush out some possible debris caused by the wound. However, the main reason for bleeding is to enable the formation of a clot, which effectively plugs the damaged area and rapidly reseals the body. Bleeding may last minutes, to hours and possibly longer in really severe trauma cases. The amount of bleeding and duration will depend partly on the vascularity of the injured tissues and the severity of the injury. Muscle tissue is highly vascular and so tends to bleed a lot, unlike ligaments. Trauma or wounding and bleeding also initiates the process for the next phase in the tissue healing cycle.
During this phase, the body sends specialist cells to clear the wound area of bacteria, pathogens, debris and dead cells. One usually notices heat, pain, swelling and changes to tissue function or movement at this stage. This phase is necessary as besides cleaning the trauma area, it also helps initiate the next phase of the healing cycle. The inflammatory phase can last anywhere from hours to weeks, depending on the factors highlighted earlier.
The healing environment during the proliferation phase can make a significant difference in terms of the tissue healing and the end outcome. In many respects, this phase is the foundation for the new tissues, and any later tissue remodelling will be affected by how well this phase goes. During this phase, the body starts to grow a new extracellular matrix and lay down a supportive network of collagen fibres. These collagen fibres are thicker and less elastic than the those found in normal tissues and have the primary aim of rapidly support the wounded area. The edges of the wound also begin contracting or closing up as the new collagen matrix stabilises the damaged area. At this stage, the tissues are far from normal strength (possibly 50%) and can easily be injured again. The proliferation phase is a reasonably efficient (non-resource intensive) process, which could certainly be critical for one's survival. The proliferation phase can also take anywhere from hours to months to conclude.
The final phase of tissue healing can take days to years depending on the severity of the trauma (wounding) and healing environment. During the maturation phase, the body performs tissue remodelling, which in many respects is an attempt to "tidy" or "clean-up" and improve the function of the hastily repaired tissues. Again, the final result will never be as good at the original tissues, in part due to the way the repair process happened earlier on.
Collagen fibres in normal healthy tissue are finer and have a more random multidirectional appearance. The collagen fibres in normal tissues are sometimes referred to as "basketweave" in appearance. Scar tissue tends to have thicker collagen fibres, which are cross-linked and have a unidirectional pattern. These differences in collagen fibre thickness, type and fibre direction affect the specific strength and extensibility (elasticity) of said tissues. Normal skin typically has multidirectional properties relating to elastic flexibility and strength. However, scar tissues are unidirectional and possess less strength and elasticity. If one looks at a scar on the skin, then one can see that the tissue has a different texture to normal healthy skin and also appears stretched. Scar tissue also has different properties to healthy skin and has fewer blood vessels, lymphatics, lacks sweat glands, hair follicles and lacks sebaceous glands. Sebaceous glands produce an oily or waxy substance called Sebum. Sebum performs several essential functions including, waterproofing the skin, lubricating the skin and hair follicles, protecting against bacterial and fungal infections. Pigmentation is also different from healthy skin due to a reduction in melanin levels within the scar tissues. Even though Scar Tissue is not as good as the original tissue pre-injury, it is usually an acceptable alternative. Skin is not the only collagen-based tissue within the body, and other tissues include (ligaments, tendons, fascia, cartilage, etc.). The healing process for all tissues within the body is similar, though only the skin has structures like (hair follicles, sebum glands, etc.). Hence, as with skin, there are changes within tissue structures as a result of wounding and healing, which impact the collagen structure layout and thus, tissue properties.
Scar tissue more than skin deep
Although many people may not realise it, tissue damage can easily be more than skin deep. A classic example of this would be a contusion injury, which typically involves some form of blunt force trauma. Such an injury may not produce any visible scarring to the skin unless there is a laceration. However, the wound can create a multitude of damage to the tissues at the point of impact and further afield. A contusion injury can be severe and even involve fractures or organ damage. Such injuries will still result in the typical phases of the healing process, though internally and this can hide the severity of damage in the early stages. As with most traumas, one is likely to notice bruising, swelling, heat and pain, and this can easily extend far beyond the site of injury. Hence, after the healing process has concluded, one may find that there is a combination of dysfunctional and scar tissues. The Myotherapist author has experienced this first hand after a knee injury in the late '90s, which resulted in his knee swelling to the same size as his thigh. The initial injury resulted in an arthroscopy on the knee and the removal of some damaged menisci. In effect, this meant that the knee tissues were "inflated" or stretched for a second time, after the initial injury. The knee subsequently never felt quite the same again and nor did the thigh muscles on the affected leg. It was not until the author retrained as a Chiropractor and Soft Tissue Therapist, that he could understand what he was feeling and why. Even though the original injury was knee-related, there were still dysfunctional tissues in the upper thigh nearly twenty years after the initial injury. There was also a lot of scar tissue around the knee itself. It was possible to vastly improve the dysfunctional nature of these injured tissues with a combination of advanced musculoskeletal and soft tissue techniques.
The differing physiological characteristics of scar tissue when compared to healthy tissues, also impact tensile forces within the body and thus biotensegrity. Scar Tissue will behave differently to healthy tissue while under load and will equally change loads on other tissues by its very existence. That said the body has a mechanism to deal with such changes, including adaption. Hence, adaptive changes continue after healing and not just at the time of injury and during healing. Over time, multiple adaptions to injuries can result in irritation to other and seemingly unrelated areas of the body. Each adaption leads to changes in Biotensegrity, and these can have an effect on other underlying tissues, structures and even result in further adaptions. As per the Adaption article, adaptions have consequences be they positive or negative.
Treatment Perspective (structure and function)
The topics of trauma, tissue healing, adaptions and biotensegrity are inextricably linked and can impact both structure and function. Hence, for treatment to be effective, one needs to consider the interrelationships between these topics and the consequences or symptoms that they produce. For the sake of this article, "structure" will refer to bones and joint complexes and, "function" will refer to soft tissues acting on bones and joint structures. Trauma or wounding can have a physiological effect on structure and function, but equally adaptive changes can also have an impact. Furthermore, "structure" can affect "function" and vice versa. Hence, treatment needs to deal with both the physiological and adaptive aspects of "structure" and "function". There are limits on what a practitioner working in the field of physical medicine can achieve concerning the physiological changes associated with "structure" and "function" and injured tissues. Currently, as of the time of writing, there is no substantial and conclusive evidence that manual therapies can significantly change the physiological makeup of scar tissue. That said there is not a tremendous amount of research in the area and studies cost time and money. However, over the years, the author has found that some soft-tissue techniques can appear to be highly effective at improving the functionality of scar tissue. To date, the author has found that it is possible to make functional improvements to both relatively new scar tissue and historical scar tissue. Some consumers have presented with relatively minor scar tissue and others from extensive trauma and had not initially sought treatment purely based on the scar tissue.
Why the bike cog images?
The two sets of bike cog images perfectly illustrate the relationship between structure and function and the reciprocal nature of the relationship. The structural integrity of the well maintained and oiled cogs and chain affects both overall function and structural wear and tear. The rusty cogs and chain reduces overall function and also results in an increased rate of wear and tear. The result is that the bike will need to have the chain, and both sets of front and rear cogs replaced sooner, which could prove expensive. It would be much easier to maintain the bike with a touch of maintenance cleaning and some oil. Basic maintenance would be far cheaper and result in improved longevity for the parts.
Although the author has found that one can effectively address "structural" changes in symmetry, there are limits. Equally, there is no evidence that Chiropractors and even soft tissue techniques can create anatomical structural changes caused by physical trauma or congenital origin. If a bone or joint structure has developed incorrectly (congenital), then manual therapy cannot change this. Equally, if a bone has been shortened or lengthened due to trauma, then such physical changes may only be addressable via other types of intervention. For example, one could address a physical leg length difference with a heel lift or altered footwear. Other conditions, including sever ligament laxity, may require surgical intervention. Such, changes have consequences relating to adaption and biotensegrity, much like certain hobbies and habitual behaviours can have an impact. These consequences can easily be managed via manual therapies and through maintenance work, and this can often be preferable to the risk of creating further trauma.
Adaption to structural changes)
The body will also adapt to such structural changes regardless of any other additional interventions to correct physical anatomical structural changes. However, as mentioned in the adaption article, adaptions usually have consequences. The author knows this well after sustaining at least two, grade two ankle inversion injuries on the same side and damaging his opposite knee. Such injuries occurred over a continued time within the Elite British forces environment. The injuries have resulted in varying levels of ligament laxity, which has consequences for other tissues and structures. The author manages these unwanted consequences of adaption through a mix of advanced musculoskeletal techniques (dealing with the structural aspects) and soft tissue therapy (to deal with the functional changes). A high degree of self-awareness has enabled the author to deal with the consequences of dysfunctional adaptions before they become a problem. The vast majority of people that the author sees in a clinic environment have relatively minor anatomical structural changes due to trauma. For example, a consumer/patient may have experienced a muscle spasm(s) due to gradual and cumulative adaptions caused by a specific habitual behaviour. Muscle spasms can prove extremely painful and result in multiple further adaptions, as the body tries to avoid pain.
It is relatively common to see consumers who have been experiencing symptoms for months or years and yet who have never sought treatment. There may still not be any significant anatomical structural changes depending on many factors, just many adaptions. The combination of techniques addressing structure and soft-tissue therapy works exceptionally well in these cases, as is it relatively easy to address structural and functional changes. However, adaptions also become learnt or second nature, so it is also necessary to address this aspect in treatment, and there are multiple parts to effectively doing this. Frequently, a consumer/patient will have adapted a particular way of moving to avoid pain, and this pattern can become learnt and even create a subconscious fear of moving differently. For example, historically, a particular movement may have caused severe pain, and therefore the consumer/patient is fearful of attempting that movement. The entire fear process can result in a self-fulling prophecy due to the initiation of the "Fight, Flight, Freeze" response. Such a response affects multiple systems, including the musculoskeletal system and muscles, which become tenser as a way of "armouring" the body. Tensed muscles are likely to impact "function" and how easily particular joint structures move when performing a specific movement.
Even after treating "structure" and "function" tissues will have adapted to the lack of use or misuse (dysfunctional movement). Also, the consumer/patient will have adapted to using the treated tissues in a particular way, and this becomes learnt behaviour. The fear of using the tissues correctly can also lead to a re-enforcement of the historical and dysfunctional movement patterns. In essence, the same input is going to equal the same output, meaning the consumer/patient is only likely to benefit at the time of treatment and then regress. Tissues can often feel weak, ache or fatigue quickly in the short-term after treatment and even up to 8 days. Even areas that did not receive treatment may experience similar sensations or ache. Dysfunctional movement patterns due to injury will have resulted in some tissues being over utilised and others not being utilised. Post-treatment tissues will have to work differently and may not have had to work correctly for years. Hence, tissues will have to adapt to these changes, and this explains some of the post-treatment experiences.
One of the best aspects of the author's job is being able to improve the standard of a consumers life markedly. It is always rewarding to see the apprehension on a consumers face change to surprise, after being assessed, treated and then being able to perform a previously painful movement. However, the process is not quite as simplistic as that.
The article was written by Terry Davis MChiro, BSc (Hons), Adv. Dip. Rem. Massag., Cert. WHS.
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About the Author
As of December 31st 2020, the author chose to leave the Chiropractic profession and pursue studies within the Physiotherapy field. He no longer works as a Chiropractor and works as a Myotherapist in Morningside, Brisbane. The author possesses an unusual background for somebody who trained as a Chiropractor (McTimoney). His education, training, and practical experience span over two decades and relate to both health's physical and mental aspects. He has also needed to push his own body and mind to the limits of physical and psychological endurance as part of his time serving in Britain's elite military forces. His education includes a bachelor of science degree in Business Management, with a specialisation in psychology and mental health in the workplace, an Integrated Masters in Chiropractic, MChiro and a multitude of soft-tissue therapy qualifications (see the about section for more details). His soft tissue qualifications range from certificate level right through to a BTEC Level 5 Advanced Diploma in Clinical Sports and Remedial Massage Therapy. Terry also has extensive experience in security, work, health and safety and holds relevant certifications. He has also taught as a senior course coach at Advanced Diploma level (Myotherapy / Musculoskeletal Therapy) in Australia, both theoretical and practical aspects including advanced Myofascial Release Techniques and has certification in training and assessment. Terry will have taught many of the first students to train as Myotherapists in Brisbane. Terry's combination of knowledge through education, training, elite military service, and personal injury history has paid dividends for the consumers he sees and has treated over the last 15 years. He has extensive experience treating chronic pain and work and sports-related musculoskeletal injuries. Terry is still very active and enjoys distance running, kayaking, mountain biking and endurance-type activities.