There are three major types of muscles injuries: contusion, strain, or laceration. Contusion is caused by a direct and compressive force such as a direct blow. Muscle strain is more often the result of tensile force (tension) beyond what the muscle can stretch. And of course, a laceration or cut is the result of sharp trauma through the skin and fascia down to the muscle.
The successful treatment of muscle injuries depends on understanding what phase of healing is taking place. In the early days (first week) after an injury, the body mounts an inflammatory response. This is sometimes referred to as the destructive phase.
It is during this period of time that the macrophages are released. Macrophages are from the immune system and are designed to destroy damaged, bleeding, or injured cells. Application of the R.I.C.E. approach (Rest, Ice, Compression, Elevation) is the most often recommended treatment during this early acute phase of muscle injury.
But there is really no convincing evidence that this treatment is an effective way to treat soft tissue injuries. In fact, in animal studies, scientists have shown that applying ice too long can actually reduce blood flow to the area impairing recovery. And other studies using compression bandages right away after injury (within the first five minutes) does not decrease the amount of swelling or speed up healing.
Whether or not to immobilize the muscle (in a splint or cast) remains a point of debate and controversy. On the one hand, keeping the muscle from moving during the early healing (destructive) phase can minimize the gap that develops when the ruptured muscle stumps pull apart. As the body sets up a collagen scaffold that will be filled in with repair cells, a smaller gap between the injured tissue means a smaller scar.
On the other hand, immobilizing the damaged soft tissue too long can cause excessive scarring. Since scar tissue is less flexible, the muscle is at risk of reinjury under lower loads or force compared with normal, healthy muscles. And there is clear evidence that early movement aids the regenerating muscle fibers to heal in an organized fashion. With early mobilization and better tissue alignment, fewer adhesions can form.
Scar tissue formation and tissue regeneration takes place in stages during the repair and remodeling phase. Repair occurs two to six weeks after the injury. Remodeling begins around week seven and extends weeks to several months following the initial trauma.
The process of tissue regeneration and scar formation is orderly but complex. The formation of scar tissue undergoes several steps from immature scar tissue to mature scar development. Connective tissue scarring is strong to help prevent further injury or rerupture but it is not as flexible as the myofibrils of normal, healthy muscle.
Treatment also depends on the severity of muscle injuries (mild, moderate, or severe). Accompanying swelling, loss of motion, tearing of muscle fibers, and loss of function help determine how the muscle injury is classified. Mild injuries usually have only minor swelling and pain with no loss of motion or function. Complete rupture of a muscle will be obvious when the patient cannot contract or use that muscle to move the body part (e.g., arm, leg).
Whereas nonsteroidal antiinflammatory drugs (NSAIDs) were once routinely prescribed after muscle injury, more recent (animal) testing has brought about a change in thinking here as well. For example, there is evidence that these drugs can delay the destruction of damaged cells thus slowing repair and regeneration of the muscle tissue. Likewise, the use of steroids has been shown (again in animals only so far) to permanently impair healing.
Right now, researchers are studying other pharmacologic agents in the treatment of muscle injuries. Other potential therapies under investigation include platelet-rich plasma, curcumin, angiotensin II receptor blockers, and suramin. Each of these approaches has a different benefit and effect on the healing tissue. Nonpharmacologic options being studied include therapeutic ultrasound and hyperbaric oxygen therapy.
With the large number of people engaged in athletics and sports that result in muscle injuries, finding more effective treatments is important. Aiding and enhancing the healing process can help to prevent chronic pain and dysfunction and perhaps even prevent injury recurrence.
For competitive athletes, effective treatment that can get them back on the playing field or court would be very welcome. Understanding the type and severity of injury and planning treatment specific to the body’s healing responses with minimal delay in return to sports is the goal.