Common Mechanisms of Inflammation and Soft Tissue Healing

Common Mechanisms of Inflammation and Soft Tissue Healing

 By Dr. Matt Fontaine When soft tissues are stressed beyond their biomechanical yield strength (for example when a tendon is stretched more than 4% of it’s resting length), microtearing must occur.  The normal response of microtearing of muscle, fascia, collagen etc. is inflammation.  If the injured area is rested, the initial inflammation should reduce in about 48-72 hours following the injury.  The body can then begin to repair and remodel and  a normal scar along the lines of stress will result. Figure:  Repetitive Motion Causes Soft Tissue Injury, ART is the key to resolve Soft Tissue Injury

How Soft Tissue Injuries Occur

If excessive overuse or immobilization occurs, increased fibrous scar tissue will result, which may spread and become tethered to surrounding normal tissue.  The normal elastic type I collagen in healthy muscle, tendon, and fascia is replaced by the inelastic type III collagen.  Now there is muscle stuck to other muscle and there is a resultant loss of internal glide of muscle and fascia between layers of muscle.  Normal layers of muscle and fascia glide on each other, crossing different directions, like silk on silk.  When adhesions are present, the fascia becomes sticky and muscle layers become stuck like tape or Velcro.  When nerves travel through or traverse through these fascial layers of  adhesed muscle tissue, the nerves can become entrapped like dental floss stuck between two pieces of Velcro.

A.  Normal muscle and fascial layers overlap and often run at different angles to each other.  This picture depicts how normal healthy muscle and fascia should glide on each other like silk on silk. B.  When scar tissue forms as a result of repetitive motion and injury, muscle and fascia get stuck together like velcro.  Often nerves travel  between these muscle and fascial layers and can become entrapped, causing burning, pain, numbness, tingling, and weakness. C.  Picture of a spaggetti noodle running over a muscle/fascial layer.  Often times nerves are the size of dental floss and can easily become entrapped between layers of tight muscles. Fascia, when healthy forms a free gliding interface between and within muscles, allowing free movement to occur.  When fascia, muscles, tendons, and ligaments get mechanically overloaded, injury can occur resulting in fibrosis and adhesions that disrupt the “sliding and gliding” of tissues. Active Release Techniques ®  is a patented, state of the ART soft tissue movement based treatment that is used to locate and break down scar tissue that results from soft tissue injuries to muscles, tendons, ligaments, fascia, and nerves.

Increased fibrous tissue results in loss of mobility and extensibility of the tissues.  Loss of extensibility means loss of function.  Loss of function results in reactivation of the tissue during normal use and a viscous cycle of microtearing-inflammation- scarring ensue (Cumulative Injury Cycle).

The scar itself may become a source of nociception stimulation (pain generating tissue).  It is well accepted in today’s medical literature that early mobilization of injured tissues results in repair with reduced scar tissue formation. What about acute injury, for instance say a hamstring or groin pull? There are grades of severity of muscle tearing.  Grade I, II, III.  The severity of the tearing and the amount of bleeding within the muscle if there is any, determine how quickly soft tissue manual treatment and joint manipulation can be rendered.  If severe enough tearing (grade II or III), there will be marked pain and loss of ROM.  A grade III will likely require surgical repair.  Grade II injury will likely be treated with ice, NSAID’s or natural anti-inflammatories for 2-8 weeks.  During that time, gentle foam rolling and stretching may be added to lightly mobilize scar tissue as it is laid down.  After a certain amount of scarring has occurred, soft tissue manual therapy like ART and Graston or IASTM (Instrument Assisted Soft Tissue Manual Therapy) should be started. With a moderate to severe degree of tearing, we basically need to let the body heal itself by laying down scar tissue.  After that has occurred, which may take 2-6 weeks or so, then we can utilize manual therapy to release scar tissue and restore gliding and ROM.  Eccentric stretching is often helpful to improve tensile strength of tendons.   What is the difference between acute fracture healing and soft tissue healing? With a fracture, the broken bone can be set, placed in a cast, and in most cases in 4-8 weeks it heals.  Acute inflammation typically resolves in 48-72 hrs if no further injury occurs and the area is immobilized.  Because the injured body part is immobilized, the swelling, edema and inflammation can reduce, pain resolves, and healing begins. With soft tissue injuries like repetitive stress (shin splints, tennis elbow, groin strain etc.) and even acute muscle and ligament tearing, the body parts are usually not immobilized.  If there are, as is the case with a severe knee or ankle sprain, ligament damage occurs during the trauma.  Ligaments stretch like plastic, once they stretch beyond a certain point, they do not go back to their original length.  With muscle and fascial microtrauma, scarring and adhesion formation does occur.  However, because the offending activity is usually continued (ie: swimming, biking, running, lifting,  sport etc.) the repetitive motion continues to cause friction and tension which creates further injury and inflammation.  What happens is that a low grade inflammation persists, and that keeps the injured body tissue stuck in the inflammatory phase.  Because the inflammation is low grade, it flies under the body’s alert radar. Severe acute trauma creates such tissue damage, that the body’s fire alarm sounds, and the body immediately begins to work.  The body region swells, muscles guard to prevent movement, and then body eventually goes through the three phases of healing.  This does not occur with repetitive overuse.  The injury perpetuates itself. This is also the case with stress fractures that do not heal properly.  Often they heal incompletely, and then the activity or sport resumes, like running.  Pain will persist.  Often times surgeons will have to make a “bad situation worse” in order for the body to heal.  They will often surgically completely fracture the bone.   This signals the body’s fire alarm that there is major trauma.  Once the signal is sounded, the body can then mobilize all it’s forces to guard the injury(inflammation, muscle guarding, casting) and then the body can repair and remodel. In Summary,  for most soft tissue injuries that occur over time due to repetitive motion, the best attack usually entails the following:

  • avoiding painful activities or reducing the volume and or intensity of activities like running, swimming, biking, lifting, etc.
  • See a sports medicine professional who can properly evaluate the injury.
  • Optimally you want to get a Functional Movement Screen™ which can detect muscle imbalances, and evaluate how your body moves.  This can detect underlying causes of the injury that need to be addressed.
  • Begin implementing foam roller and stretching.
  • Get Active Release Techniques® to detect and resolve adhesions within injured soft tissues to restore proper muscle and fascial gliding.
  • Manipulation to restore proper motion to joints.
  • A comprehensive but progressive rehabilitative program designed to retrain proper movement, create mobility and stability to the joints that need it.  Emphasis should be placed on core stability and ultimately progress to a functional program for return to sport or activity.