of wounds and fractures

Chapter 14 Healing of wounds and fractures




Questions


image What are the processes involved in wound and fracture healing?

image What factors may interfere with efficient wound and fracture healing?



Wound healing


Healing of wounds involves inflammation, granulation tissue formation and fibrosis. The process is controlled by a complex network of cell–cell and cell–matrix interactions. Inflammatory cells are required to fight infection, especially in contaminated wounds. Phagocytes remove necrotic tissue and blood clot and also attempt to digest particles of foreign material contaminating the wound (the last is characterized histologically by foreign body giant cells). Granulation tissue revascularizes the damaged tissue, and the deposition of collagen and other matrix materials leads to the formation of a scar (Ch. 7).


If there has been a breach in an epithelial surface, epithelial cells from the edge of the wound grow over the granulation tissue, reepithelializing the damaged area (Fig. 3.14.1). This process is also controlled by a complex series of cell–cell and cell–matrix interactions.


image image

Fig. 3.14.1 Re-epithelialization in a wound.



Factors inhibiting wound healing


There are a number of factors that can inhibit wound healing.


Persistent infection. The inflammation associated with defence against pathogens inhibits healing.

Presence of a foreign body. A foreign body provides a site where bacteria may be protected from the host defence mechanisms, because the foreign material inhibits access of antibodies and inflammatory cells. Furthermore, if the foreign body is indigestible, granulation tissue cannot organize it. Therefore, foreign bodies can be said to act as a ‘sanctuary site’ for bacteria.

Stasis. Contaminating bacteria may be removed by the flow of secretions and excretions (e.g. tears and urine). If stasis (i.e. lack of flow) of a fluid occurs, contaminating bacteria can multiply within it. For example, in urinary outflow obstruction associated with incomplete emptying of the bladder, any bacteria that manage to ascend the urethra into the bladder have a chance to multiply in the urine and cause urinary tract infection.
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Jul 3, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on of wounds and fractures
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