Review Question - QID 217217

This patient who presents with a severe contracture in his elbow 3 months after a traumatic injury would most likely have hypertrophic deposition of type 1 collagen into the wound bed.

The process of normal wound healing occurs through phases including the hemostatic phase, the inflammatory phase, the proliferative phase, and the remodeling phase. The hemostatic phase involves initial clot formation through platelet aggregation and small vessel constriction to prevent further bleeding. The inflammatory phase then commences with neutrophil and macrophage infiltration of local tissues to remove debris and to create a clean wound bed. The proliferative phase is then characterized by fibroblast deposition of type 3 collagen and glycoproteins in order to create granulation tissue. Finally, the remodeling phase occurs when the type 3 collagen is converted to type 1 collagen. In some cases, this remodeling phase becomes hypertrophic resulting in overactive type 1 collagen deposition resulting in fibrosis, increased tensile strength of the soft tissue, and the creation of a contracture.

Nedelec et al. discuss the processes that regulate wound contraction. They find that type 1 collagen and myofibroblasts are key players in the development of a remodeled wound as well as the pathophysiology of contracture formation. They recommend understanding these processes to better advise patients about wound healing.

Incorrect Answers:
Answer 1: Angiogenesis and type 3 collagen deposition would be seen in the proliferative phase of wound healing. This occurs between 3 days and several weeks of the injury and would be characterized by granulation tissue. Notably, this tissue does not provide tensile strength and would not restrict motion.

Answer 3: Neutrophil and macrophage infiltration of extravascular tissues would be seen in the inflammatory phase of wound healing and would result in clearance of debris from the wound. This occurs within the first 3 days of the injury and does not restrict motion.

Answer 4: Platelet aggregation and small vessel constriction would be seen in the hemostatic phase of wound healing. This occurs within minutes of the injury and provides the initial method of stopping further hemorrhage.

Answer 5: Vessel maturation and type 1 collagen conversion would be seen in the remodeling phase of wound healing. While this tissue provides tensile strength, only hypertrophic deposition would lead to contracture formation and restriction of motion.

Bullet Summary:
Contracture formation is characterized by hypertrophic deposition of type 1 collagen.