A 45-year-old male sustains a traumatic injury at work and presents to the emergency department with a deep laceration on the palm of his right hand. Three weeks later, actin-containing fibroblasts and increased metalloproteinase activity are detected at the site of injury. These findings are most likely related to which of the following complications?

Question

A 45-year-old male sustains a traumatic injury at work and presents to the emergency department with a deep laceration on the palm of his right hand.  Three weeks later, actin-containing fibroblasts and increased metalloproteinase activity are detected at the site of injury.  These findings are most likely related to which of the following complications?

Quizplus · Accepted Answer

Secreted by several different cell types (eg, fibroblasts, macrophages, neutrophils, synovial cells, some epithelial cells), matrix metalloproteinases (MMPs) primarily function in the degradation of collagen and other proteins in the extracellular matrix. MMP activity is important in wound healing, as it encourages both myofibroblast accumulation at the wound edges and scar tissue remodeling. The amassed myofibroblasts initiate wound contraction during healing by second intention. Contractures may occur when unusually pronounced MMP activity results in excessive wound contraction. (Choice A) Wound dehiscence is the rupturing of a previously closed wound, and can result from insufficient granulation and scar tissue formation, inadequate wound contraction, or excessive mechanical stress. Such wound rupture most commonly occurs in abdominal wounds that are subject to increased intraabdominal pressure, which is not the case with this patient. (Choice B) Ulceration of a wound typically results from inadequate vascularization during healing and is not associated with excessive matrix metalloproteinase or myofibroblast activity. Common sites of ulceration include lower extremity wounds in conjunction with atherosclerotic peripheral vascular disease. (Choice C) Local infection is the most important cause of delayed wound healing. The delay results from persistent tissue injury and inflammation and is not known to be specifically related to excessive matrix metalloproteinase or myofibroblast activity. (Choice D) Keloids are hypertrophic scars in which excessive collagenous scar tissue deposited by fibroblasts permanently extends beyond the margins of the original wound. Keloids are not known to be specifically related to excessive matrix metalloproteinase or myofibroblast activity. Educational Objective: During wound healing, excessive matrix metalloproteinase activity and myofibroblast accumulation in the wound margins can result in contracture. Contractures produce deformities of the wound and surrounding tissues, most often on the palms, soles, anterior thorax, or at serious burn sites.

A 45-Year-Old Male Sustains a Traumatic Injury at Work and Presents