What Is Prolotherapy?
Although this discussion concerns the ligaments, the deepest of the soft tissue structures, the skin heals in almost the same manner. Small skin cuts heal in much the same way as deeper structures. The main difference is that ligaments and other deep tissues do so without scarring. Figure 1 shows the phases of wound healing.
Inflammation is the initial phase of wound healing. For the first 100 hours after an injury, a blood clot forms, laying the groundwork for many cellular and chemical activities. The blood clot traps platelets, small particles in the blood that contain many growth factors that guide this phase. The blood clot also captures and attracts many other cells. Some of these cells kill the bacteria that have entered the wound (leukocytes), others clean up the dead tissue in the wound (neutrophils), and still others become involved in the repair process (macrophages).
Some of the chemical reactions produce substances in particular, prostaglandin that cause irritation of the pain fibers. Other chemicals released by the injured tissue and the platelets not only send signals to the healthy cells adjacent to the wound and the incoming macrophages specifying which ligament is injured but also direct these cells to download the repair information from their genes. These cells multiply with the “genetic blueprint” for the repair. Once the chemical reactions are finished and the cells have obtained the necessary genetic information, the inflammation phase ends.
Approximately 100 hours after the injury, the granulation phase begins during which many cells multiply and change shape. Some macrophages turn into fibroblasts, which make collagen. Existing blood vessels are stimulated to make new ones that supply the new tissue with oxygen and nutrients. As a coordinated unit, the fibroblasts and blood vessels move into the wound, creating the granular appearance for which this phase is named. This cycle of creating collagen, the raw materials of a ligament, continues for the next 3 to 5 weeks. As this phase ends, the collagen begins to reorganize into the matrix of the new ligament.
The remodeling phase, which is more difficult to observe, takes about 12 weeks. During remodeling, the superficial blood clot drops off the skin. The wounded area underneath is still red and slightly raised but usually not tender. In an injured ligament, the collagen resembles gelatin more than a ligament. Within this disorganized collagen, a few fibroblasts, or the cells that make collagen, evolve into a different kind of cell that begins to produce muscle contractile fibers in response to stress or the constant tugging of the new tissue by movement. These cells with powerful contractile fibers are called myofibroblasts. (See Figures 2 and 3)
Myofibroblasts begin attaching to some of the disorganized collagen, contracting and pulling the adjacent collagen into a tighter, more compact matrix. In the area of the compacted matrix, new collagen cements the fibers in their shortened positions. This process continues until all of the myofibroblasts are shielded from the stress by the new ligament tissue; then they disappear. (See Figures 4 and 5) At the end of the remodeling phase, the gelatin has been organized into a new ligament that has been repaired to its original strength and length and is indistinguishable from the original. In other words, there is no scar tissue. This process gives humans and animals the resources to repair minor injuries in such a way that survivability is not affected.
Under which conditions can prolotherapy complement the natural wound-healing and tissue process in tightening a lax ligament?
- Ligament strain caused by poor posture or poor technique while doing any activity or practicing any sport.
- Prevention of ligament healing caused by a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin or ibuprofen taken for pain relief after an injury. NSAIDs inhibit some of the early chemical reactions in the inflammatory phase, particularly the production of prostaglandin E2. A lower prostaglandin level means fewer macrophages attracted to a wound.
- Decrease in collagen production in the inflammation and granulation phases of wound healing and tissue repair caused by inadequate protein intake or protein that is redirected to repair vital organs after a major accident or trauma.
- Decrease in the blood supply to the injured tissue and in the quality of the repair process caused by smoking.