In the process of wound healing, matrix metalloproteinases (MMPs) play a key role in remodeling. During the remodeling phase, type III collagen is replaced by type I collagen, and wound tensile strength at 6 weeks is approximately what percentage of normal unwounded skin?

• A 25%
• B 100%
• C 50%
• D 80% ✓

Explanation

Wound tensile strength recovers progressively during the remodeling phase: at 3 weeks it is approximately 20% of normal; at 6 weeks approximately 80%; at 3 months approximately 80–90%; maximum is 80% of unwounded skin even after complete healing, explaining why healed incisions remain relatively vulnerable. Type III collagen (provisional matrix) is replaced by type I collagen in a 4:1 ratio (normal skin is 4:1 type I:III; wounds initially have more type III). MMPs degrade old collagen while TIMPs regulate MMP activity. Keloid and hypertrophic scars result from dysregulation of this balance.

Reference: Bailey & Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.